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Public Class Form1
Private Sub BtnCalculateRevenue_Click(sender As Object, e As EventArgs) Handles BtnCalculateRevenue.Click
Dim intvalue As Integer = CInt(TxtInputClassA.Text)
Dim intvalue2 As Integer = CInt(TxtInputClassB.Text)
Dim intvalue3 As Integer = CInt(TxtinputClassC.Text)
Dim total As Double
Try
LblStatus.Text = String.Empty
LblClassAResult.Text = (intvalue * 15).ToString("c")
LblClassBResult.Text = (intvalue2 * 12).ToString("c")
LblClassCResult.Text = (intvalue3 * 9).ToString("c")
total = CDbl((intvalue * 15) + (intvalue2 * 12) + (intvalue3 * 9))
LblTotal.Text = total.ToString("c")
Catch
LblStatus.Text = "Please Enter a Number"
End Try
End Sub
Private Sub BtnExit_Click(sender As Object, e As EventArgs) Handles BtnExit.Click
Me.Close()
End Sub
Private Sub BtnClear_Click(sender As Object, e As EventArgs) Handles BtnClear.Click
TxtInputClassA.Clear()
TxtInputClassB.Clear()
TxtinputClassC.Clear()
LblClassAResult.Text = String.Empty
LblClassBResult.Text = String.Empty
LblClassCResult.Text = String.Empty
LblTotal.Text = String.Empty
End Sub
End Class
VB Entering a Non_Numeric value crashes the program
Validation is built right into Windows Forms so you should make use of it. If you want to force the user to enter numbers in each of three TextBoxes then you can do this:
Private Sub TextBoxes_Validating(sender As Object, e As ComponentModel.CancelEventArgs) Handles TextBox3.Validating, TextBox2.Validating, TextBox1.Validating
Dim tb = DirectCast(sender, TextBox)
If Not Integer.TryParse(tb.Text, Nothing) Then
'Select all the invalid text and highlight it.
tb.SelectAll()
tb.HideSelection = False
MessageBox.Show("Please enter a whole number",
"Invalid Input",
MessageBoxButtons.OK,
MessageBoxIcon.Exclamation)
'Remove highlight when TextBox is not focused.
tb.HideSelection = True
'Don't let the control lose focus while data is invalid.
e.Cancel = True
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ValidateChildren() Then
'All data is valid so proceed.
Dim n1 = CInt(TextBox1.Text)
Dim n2 = CInt(TextBox2.Text)
Dim n3 = CInt(TextBox3.Text)
'...
End If
End Sub
The ValidateChildren method will raise the Validating event for every control on the form and return False if any fail validation, i.e. e.Cancel is set to True in any event handlers, so that ensures that even controls that never received focus will be validated before the data is used.
Its bombing out on your cast "CInt(*value*)" so you can fix the code a couple ways. You can move your try above the casts like...
Try
Dim intvalue As Integer = CInt(TxtInputClassA.Text)
Dim intvalue2 As Integer = CInt(TxtInputClassB.Text)
Dim intvalue3 As Integer = CInt(TxtinputClassC.Text)
Dim total As Double
LblStatus.Text = String.Empty
You can do a data validation on your inputs and exit if they aren't all numeric (put this above your Dim intvalue code)
For Each value As String In {TxtInputClassA.Text, TxtInputClassA.Text, TxtInputClassA.Text}
If Not IsNumeric(TxtInputClassA.Text) Then
LblStatus.Text = "Please Enter a Number"
Exit Sub
End If
Next
Instead of casting as an int, use the tryparse method on Int32...
Dim intvalue As Integer
If Not Int32.TryParse(TxtInputClassA.Text, intvalue) Then
Exit Sub
End If
Or you could intercept the keypresses on each text box so that only numbers can be entered
Private Sub TxtInputClassA_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TxtInputClassA.KeyPress
If Not Char.IsDigit(e.KeyChar) Then
e.Handled = True
End If
End Sub
You can make that routine universal and append the event handler for all three text boxes like...
Private Sub EnforceOnlyNumericKeyPresses(sender As Object, e As KeyPressEventArgs) Handles TxtInputClassA.KeyPress, TxtInputClassB.KeyPress, TxtInputClassC.KeyPress
If Not Char.IsDigit(e.KeyChar) Then
e.Handled = True
End If
End Sub
Choose your favorite or do all of them, lots of choices.
Replace your textboxes with NumericUpDown controls and retrieve their .Value for your calculation. NUDs don't allow non numeric input and can have a fixed number of decimal places which may also be useful in a financial context
Okay, so how do I do the part for display summary when i checked or unchecked?
Mine is not working for some reason. Am I missing out something? I have to give students the ability to control the display of the information.
Public Class MathPractice
Private Sub rbAddition_CheckedChanged(sender As Object, e As EventArgs) Handles rbAddition.CheckedChanged
'Change the label to plus
lblPlus.Text = " + "
End Sub
Private Sub rbSubtraction_CheckedChanged(sender As Object, e As EventArgs) Handles rbSubtraction.CheckedChanged
'Change the label to minus
lblPlus.Text = "-"
Dim intlbl1 As Integer = Val(lbl1.Text)
Dim intlbl2 As Integer = Val(lbl2.Text)
If rbSubtraction.Checked Then
Do While intlbl1 < intlbl2
If rbGrade1.Checked Then
intlbl1 = Random.Next(1, 10)
ElseIf rbGrade2.Checked Then
intlbl1 = Random.Next(10, 99)
End If
Loop
lbl1.Text = intlbl1.ToString
End If
End Sub
Private Sub rbGrade1_CheckedChanged(sender As Object, e As EventArgs) Handles rbGrade1.CheckedChanged
Dim random As New Random()
'Get random numbers between 1 and 10.
If rbGrade1.Checked Then
lbl1.Text = random.Next(1, 10).ToString
lbl2.Text = random.Next(1, 10).ToString
End If
End Sub
Private Sub rbGrade2_CheckedChanged(sender As Object, e As EventArgs) Handles rbGrade2.CheckedChanged
Dim random As New Random()
random.Next(10, 99)
'Get random numbers between 10 and 99.
If rbGrade2.Checked Then
lbl1.Text = random.Next(10, 99).ToString
lbl2.Text = random.Next(10, 99).ToString
End If
End Sub
Private Sub btnCheckAnswer_Click(sender As Object, e As EventArgs) Handles btnCheckAnswer.Click
'Check the answer whether it is right or wrong
'Display a message box showing right or wrong
Dim intlbl1 As Integer = Val(lbl1.Text)
Dim intlbl2 As Integer = Val(lbl2.Text)
Dim intResult As Integer = Val(txtBoxResult.Text)
Dim btnCheckAnswer As String
Select Case lblPlus.Text
Case "+"
If intResult = intlbl1 + intlbl2 Then
btnCheckAnswer = "Correct."
Else
btnCheckAnswer = "Sorry. Try Again."
End If
Case "-"
If intResult = intlbl1 - intlbl2 Then
btnCheckAnswer = "Correct."
Else
btnCheckAnswer = "Sorry. Try Again."
End If
End Select
End Sub
Private Sub chkBoxDisplaySummary_CheckedChanged(sender As Object, e As EventArgs) Handles chkBoxDisplaySummary.CheckedChanged
'Display or hide information
If chkBoxDisplaySummary.Checked Then
GroupBox2.Visible = True
Else
GroupBox2.Visible = False
End If
End Sub
Private Sub btnClose_Click(sender As Object, e As EventArgs) Handles btnExit.Click
Me.Close()
End Sub
End Class
ok .. this should do it .. tho of course if the number in lbl2 is the biggest of the possible random numbers (10 or 99) lbl1 can never be bigger, so the code ive written could poddibly result in lbl1 and lbl2 both being 10 or 99. Anyhoe heres the code
ok ive recreated the app on my pc - there were a few errors in the original code that although it looked ok at a glance, threw things off - for example at the beginning when you assign a "+" to the lbl, you had a space either side of it, but in the checking answer logic there were no spaces. also cint on a string doesnt work when a visual studio opton called "option explicit" is turned on - having it on encourages better programming :) Also because of this "option explicit, you'll see ive added ".ToString in a few places as well
OK this is what ive got - i presume that your two sets of radio buttons are in two separate group boxes or the code would never have worked :)
have a look at the code below and compare it side by side with your original. Hope this helps. And dont forget the plus one if it does :-))
Private Sub rbAddition_CheckedChanged(sender As Object, e As EventArgs) Handles rbAddition.CheckedChanged
lblPlus.Text = "+"
End Sub
Private Sub rbSubtraction_CheckedChanged(sender As Object, e As EventArgs) Handles rbSubtraction.CheckedChanged
lblPlus.Text = "-"
Dim intlbl1 As Integer = Val(lbl1.Text)
Dim intlbl2 As Integer = Val(lbl2.Text)
If rbSubtraction.Checked Then
Do While intlbl1 < intlbl2
If rbGrade1.Checked Then
intlbl1 = random.Next(1, 10)
ElseIf rbGrade2.Checked Then
intlbl1 = random.Next(10, 99)
End If
Loop
lbl1.Text = intlbl1.ToString
End If
End Sub
Private Sub rbGrade1_CheckedChanged(sender As Object, e As EventArgs) Handles rbGrade1.CheckedChanged
Dim random As New Random()
'Get random numbers between 1 and 10.
If rbGrade1.Checked Then
lbl1.Text = random.Next(1, 10).ToString
lbl2.Text = random.Next(1, 10).ToString
End If
End Sub
Private Sub rbGrade2_CheckedChanged(sender As Object, e As EventArgs) Handles rbGrade2.CheckedChanged
Dim random As New Random()
random.Next(10, 99)
'Get random numbers between 10 and 99.
If rbGrade2.Checked Then
lbl1.Text = random.Next(10, 99).ToString
lbl2.Text = random.Next(10, 99).ToString
End If
End Sub
Private Sub btnCheckAnswer_Click(sender As Object, e As EventArgs) Handles btnCheckAnswer.Click
Dim intlbl1 As Integer = Val(lbl1.Text)
Dim intlbl2 As Integer = Val(lbl2.Text)
Dim intResult As Integer = Val(txtboxResult.Text)
Dim isTheAnswerCorrect As String
Select Case lblPlus.Text
Case "+"
If intResult = intlbl1 + intlbl2 Then
isTheAnswerCorrect = "Correct!"
Else
isTheAnswerCorrect = "Sorry. Try Again"
End If
Case "-"
If intResult = intlbl1 - intlbl2 Then
isTheAnswerCorrect = "Correct!"
Else
isTheAnswerCorrect = "Sorry. Try Again"
End If
End Select
MsgBox(isTheAnswerCorrect)
End Sub
Private Sub btnClose_Click(sender As Object, e As EventArgs) Handles btnExit.Click
Me.Close()
End Sub
if cint(lbl1.Text)>=cint(lbl2.Text) then
intResult = cint(lbl1.Text)-cint(lbl2.Text)
else
intResult = cint(lbl2.Text)-cint(lbl1.Text)
end if
You can prompt the user to calculate the difference between two numbers(without sign(+/-)). then you can do calculation using Math.Abs()
intResult = Math.Abs(Val(lbl1.Text)-Val(lbl2.Text))
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I'm writing some code for a calculator and I keep getting this error. I have the math functions in another class but the variables from form1 are not accessible. Below is my code.
I've also tried changing my Dim variables to public but that also doesn't work.
Public Class Form1
'create a value to keep track of whether the calculation is complete so the calculator can revert to zero for new calculations
Dim state As Integer
'create values to store information on numbers and signs entered as well as the answer returned
Dim one As Double
Dim two As Double
Dim ans As Double
Dim sign As Char
Public Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'when "Return" or "Enter" Key is selected button 15 is clicked (seems to only work when textbox selected????)
Me.AcceptButton = Button15
'change the title of the form
Me.Text = "Simple Calculator"
'label the buttons logically
Button1.Text = "1"
Button2.Text = "2"
Button3.Text = "3"
Button4.Text = "4"
Button5.Text = "5"
Button6.Text = "6"
Button7.Text = "7"
Button8.Text = "8"
Button9.Text = "9"
Button10.Text = "0"
Button11.Text = "+"
Button12.Text = "-"
Button13.Text = "X"
Button14.Text = "/"
Button15.Text = "Calc"
Button16.Text = "About Me"
Button17.Text = "Clear"
'allows form to revcieve key events
Me.KeyPreview = True
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'create action when button 1 is clicked
'if state is 1 then previous calculation was solved, then clear textbox to allow for new input
If state = 1 Then
TextBox1.Text = ""
'insert 1 into textbox
Dim Int1 As Integer = 1
TextBox1.Text = TextBox1.Text & Int1
'return state of calculator to zero to designate that calculation has NOT been solved
state = 0
Else
'else insert 1 into textbox
Dim Int1 As Integer = 1
TextBox1.Text = TextBox1.Text & Int1
End If
End Sub
' the above function for each numbered button
Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int2 As Integer = 2
TextBox1.Text = TextBox1.Text & Int2
state = 0
Else
Dim Int2 As Integer = 2
TextBox1.Text = TextBox1.Text & Int2
End If
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int3 As Integer = 3
TextBox1.Text = TextBox1.Text & Int3
state = 0
Else
Dim Int3 As Integer = 3
TextBox1.Text = TextBox1.Text & Int3
End If
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int4 As Integer = 4
TextBox1.Text = TextBox1.Text & Int4
state = 0
Else
Dim Int4 As Integer = 4
TextBox1.Text = TextBox1.Text & Int4
End If
End Sub
Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int5 As Integer = 5
TextBox1.Text = TextBox1.Text & Int5
state = 0
Else
Dim Int5 As Integer = 5
TextBox1.Text = TextBox1.Text & Int5
End If
End Sub
Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int6 As Integer = 6
TextBox1.Text = TextBox1.Text & Int6
state = 0
Else
Dim Int6 As Integer = 6
TextBox1.Text = TextBox1.Text & Int6
End If
End Sub
Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button7.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int7 As Integer = 7
TextBox1.Text = TextBox1.Text & Int7
state = 0
Else
Dim Int7 As Integer = 7
TextBox1.Text = TextBox1.Text & Int7
End If
End Sub
Private Sub Button8_Click(sender As Object, e As EventArgs) Handles Button8.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int8 As Integer = 8
TextBox1.Text = TextBox1.Text & Int8
state = 0
Else
Dim Int8 As Integer = 8
TextBox1.Text = TextBox1.Text & Int8
End If
End Sub
Private Sub Button9_Click(sender As Object, e As EventArgs) Handles Button9.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int9 As Integer = 9
TextBox1.Text = TextBox1.Text & Int9
state = 0
Else
Dim Int9 As Integer = 9
TextBox1.Text = TextBox1.Text & Int9
End If
End Sub
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
If state = 1 Then
TextBox1.Text = ""
Dim Int0 As Integer = 0
TextBox1.Text = TextBox1.Text & Int0
state = 0
Else
Dim Int0 As Integer = 0
TextBox1.Text = TextBox1.Text & Int0
End If
End Sub
Private Sub Button11_Click(sender As Object, e As EventArgs) Handles Button11.Click
'create an action for when addition button is clicked
Try
'when button is clicked dim sign and text in textbox
sign = "+"
one = TextBox1.Text
TextBox1.Text = ""
Catch ex As Exception
TextBox1.Text = "Error" ' if error occurs return error in textbox
state = 1 'if error occurs return state to 1 to allow for new calculation
End Try
End Sub
'repeat the above action for remainder of arithmic functions
Private Sub Button12_Click(sender As Object, e As EventArgs) Handles Button12.Click
Try
'when button is clicked dim sign and text in textbox
sign = "-"
one = TextBox1.Text
TextBox1.Text = ""
Catch ex As Exception
TextBox1.Text = "Error" ' if error occurs return error in textbox
state = 1 'if error occurs return state to 1 to allow for new calculation
End Try
End Sub
Private Sub Button13_Click(sender As Object, e As EventArgs) Handles Button13.Click
Try
sign = "*"
one = TextBox1.Text
TextBox1.Text = ""
Catch ex As Exception
TextBox1.Text = "Error" ' if error occurs return error in textbox
state = 1 'if error occurs return state to 1 to allow for new calculation
End Try
End Sub
Private Sub Button14_Click(sender As Object, e As EventArgs) Handles Button14.Click
Try
sign = "/"
one = TextBox1.Text
TextBox1.Text = ""
Catch ex As Exception
TextBox1.Text = "Error"
state = 1 'if error occurs return state to 1 to allow for new calculation
End Try
End Sub
Private Sub Button15_Click(sender As Object, e As EventArgs) Handles Button15.Click
'run functions based on sign stored during calculation
Try
two = TextBox1.Text
If sign = "+" Then
Calculator2.Math.add()
ElseIf sign = "-" Then
Calculator2.Math.minus()
ElseIf sign = "*" Then
Calculator2.Math.multiply()
ElseIf sign = "/" Then
Calculator2.Math.divide()
End If
'if user attempts to divide by zero return divide by zero error in textbox
If TextBox1.Text = "Infinity" Then
TextBox1.Text = "Divide by Zero Error"
state = 1 'if error occurs return state to 1 to allow for new calculation
End If
Catch ex As Exception
TextBox1.Text = "Error"
state = 1 'if error occurs return state to 1 to allow for new calculation
End Try
End Sub
Private Sub Button16_Click(sender As Object, e As EventArgs) Handles Button16.Click
'create message box that provides information about author
Dim msg = "Student Name: Emily Wong" & vbCrLf & "Student Number: 0692740" ' Define the message you want to see inside the message box.
Dim title = "About Me" ' Define a title for the message box.
Dim style = MsgBoxStyle.OkOnly ' make an ok button for the msg box
Dim response = MsgBox(msg, style, title)
End Sub
Private Sub Button17_Click(sender As Object, e As EventArgs) Handles Button17.Click
'create a clear button to clear textboxes when clicked and reset state of calculator
TextBox1.Text = ""
state = 0
End Sub
And this is my other class
Public Class Math
Inherits Form1
'create funtions for add,sub, multiply, and divide features
Sub add()
ans = one + two 'creates calculation of the entered numbers
TextBox1.Text = ans 'returns answer into the textbox
state = 1 'returns state to 1 to show that calculation has occured
End Sub
Sub minus()
ans = one - two
TextBox1.Text = ans
state = 1
End Sub
Sub multiply()
ans = one * two
TextBox1.Text = ans
state = 1
End Sub
Sub divide()
ans = one / two
TextBox1.Text = ans
state = 1
End Sub
End Class
state is a private variable in Form1. You can't access from code outside of Form1. Your Math class cannot reference state. Remove the calls to state from the Math class code. An outside class should not be changing the state of another object in anycase.
Try this instead:
Public Class accounting
Dim Operand1 As Double
Dim Operand2 As Double
Dim [Operator] As String
These are the button from 1 - 0
Private Sub Button6_Click_1(sender As Object, e As EventArgs) Handles Button9.Click, Button8.Click, Button7.Click, Button6.Click, Button5.Click, Button4.Click, Button19.Click, Button12.Click, Button11.Click, Button10.Click
txtans.Text = txtans.Text & sender.text
End Sub
This button is for period/point
Private Sub Button18_Click(sender As Object, e As EventArgs) Handles Button18.Click
If InStr(txtans.Text, ".") > 0 Then
Exit Sub
Else
txtans.Text = txtans.Text & "."
End If
End Sub
This button is for clear or "C" in calculator
Private Sub Button20_Click(sender As Object, e As EventArgs) Handles Button20.Click
txtans.Text = ""
End Sub
These are for add,subtract,divide, and multiply
Private Sub Buttonadd_Click(sender As Object, e As EventArgs) Handles Button13.Click
Operand1 = Val(txtans.Text)
txtans.Text = ""
txtans.Focus()
[Operator] = "+"
End Sub
Private Sub Buttondivide_Click(sender As Object, e As EventArgs) Handles Button15.Click
Operand1 = Val(txtans.Text)
txtans.Text = ""
txtans.Focus()
[Operator] = "-"
End Sub
Private Sub Buttonsubtract_Click(sender As Object, e As EventArgs) Handles Button16.Click
Operand1 = Val(txtans.Text)
txtans.Text = ""
txtans.Focus()
[Operator] = "*"
End Sub
Private Sub Buttonmultiply_Click(sender As Object, e As EventArgs) Handles Button14.Click
Operand1 = Val(txtans.Text)
txtans.Text = ""
txtans.Focus()
[Operator] = "/"
End Sub
This button is for "=" sign
Private Sub Buttoneequal_Click(sender As Object, e As EventArgs) Handles Button17.Click
Dim Result As Double
Operand2 = Val(txtans.Text)
'If [Operator] = "+" Then
' Result = Operand1 + Operand2
'ElseIf [Operator] = "-" Then
' Result = Operand1 - Operand2
'ElseIf [Operator] = "/" Then
' Result = Operand1 / Operand2
'ElseIf [Operator] = "*" Then
' Result = Operand1 * Operand2
'End If
Select Case [Operator]
Case "+"
Result = Operand1 + Operand2
txtans.Text = Result.ToString("#,###.00")
Case "-"
Result = Operand1 - Operand2
txtans.Text = Result.ToString("#,###.00")
Case "/"
Result = Operand1 / Operand2
txtans.Text = Result.ToString("#,###.00")
Case "*"
Result = Operand1 * Operand2
txtans.Text = Result.ToString("#,###.00")
End Select
txtans.Text = Result.ToString("#,###.00")
End Sub
This button is for backspace effect.
Private Sub Buttondel_Click(sender As Object, e As EventArgs) Handles Button21.Click
If txtans.Text < " " Then
txtans.Text = Mid(txtans.Text, 1, Len(txtans.Text) - 1 + 1)
Else
txtans.Text = Mid(txtans.Text, 1, Len(txtans.Text) - 1)
End If
End Sub
Note that "txtans.text" is the textbox where the user inputs and where the output shows.
I'm fairly new to VB.net (self taught) and was just wondering if someone out there could help me out with some code. I'm not trying to do anything too involved, just have a TextBox that accepts a numeric value from 1 to 10. I don't want it to accept a string or any number above 10. If someone types a word or character an error message will appear, telling him to enter a valid number. This is what I have; obviously it's not great as I am having problems. Thanks again to anyone who can help.
If TxtBox.Text > 10 Then
MessageBox.Show("Please Enter a Number from 1 to 10")
TxtBox.Focus()
ElseIf TxtBox.Text < 10 Then
MessageBox.Show("Thank You, your rating was " & TxtBox.Text)
Total = Total + 1
ElseIf IsNumeric(TxtBox.Text) Then
MessageBox.Show("Thank you, your rating was " & ValueTxtBox.Text)
End If
ValueTxtBox.Clear()
ValueTxtBox.Focus()
You can do this with the use of Ascii integers. Put this code in the Textbox's Keypress event. e.KeyChar represents the key that's pressed. And the the built-in function Asc() converts it into its Ascii integer.
Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
'97 - 122 = Ascii codes for simple letters
'65 - 90 = Ascii codes for capital letters
'48 - 57 = Ascii codes for numbers
If Asc(e.KeyChar) <> 8 Then
If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
e.Handled = True
End If
End If
End Sub
This is what I did in order to handle both key entry and copy/paste.
Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress
If Not Char.IsNumber(e.KeyChar) AndAlso Not Char.IsControl(e.KeyChar) Then
e.Handled = True
End If
End Sub
Private Sub TextBox_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox.TextChanged
Dim digitsOnly As Regex = New Regex("[^\d]")
TextBox.Text = digitsOnly.Replace(TextBox.Text, "")
End Sub
If you want to allow decimals and negative amount, add
AndAlso Not e.KeyChar = "." AndAlso Not e.keyChar = "-"
to the if statement in the KeyPress section.
Simplest ever solution for TextBox Validation in VB.NET
First, add new VB code file in your project.
Go To Solution Explorer
Right Click to your project
Select Add > New item...
Add new VB code file (i.e. example.vb)
or press Ctrl+Shift+A
COPY & PASTE following code into this file and give it a suitable name. (i.e. KeyValidation.vb)
Imports System.Text.RegularExpressions
Module Module1
Public Enum ValidationType
Only_Numbers = 1
Only_Characters = 2
Not_Null = 3
Only_Email = 4
Phone_Number = 5
End Enum
Public Sub AssignValidation(ByRef CTRL As Windows.Forms.TextBox, ByVal Validation_Type As ValidationType)
Dim txt As Windows.Forms.TextBox = CTRL
Select Case Validation_Type
Case ValidationType.Only_Numbers
AddHandler txt.KeyPress, AddressOf number_Leave
Case ValidationType.Only_Characters
AddHandler txt.KeyPress, AddressOf OCHAR_Leave
Case ValidationType.Not_Null
AddHandler txt.Leave, AddressOf NotNull_Leave
Case ValidationType.Only_Email
AddHandler txt.Leave, AddressOf Email_Leave
Case ValidationType.Phone_Number
AddHandler txt.KeyPress, AddressOf Phonenumber_Leave
End Select
End Sub
Public Sub number_Leave(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
Dim numbers As Windows.Forms.TextBox = sender
If InStr("1234567890.", e.KeyChar) = 0 And Asc(e.KeyChar) <> 8 Or (e.KeyChar = "." And InStr(numbers.Text, ".") > 0) Then
e.KeyChar = Chr(0)
e.Handled = True
End If
End Sub
Public Sub Phonenumber_Leave(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
Dim numbers As Windows.Forms.TextBox = sender
If InStr("1234567890.()-+ ", e.KeyChar) = 0 And Asc(e.KeyChar) <> 8 Or (e.KeyChar = "." And InStr(numbers.Text, ".") > 0) Then
e.KeyChar = Chr(0)
e.Handled = True
End If
End Sub
Public Sub OCHAR_Leave(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
If InStr("1234567890!##$%^&*()_+=-", e.KeyChar) > 0 Then
e.KeyChar = Chr(0)
e.Handled = True
End If
End Sub
Public Sub NotNull_Leave(ByVal sender As Object, ByVal e As System.EventArgs)
Dim No As Windows.Forms.TextBox = sender
If No.Text.Trim = "" Then
MsgBox("This field Must be filled!")
No.Focus()
End If
End Sub
Public Sub Email_Leave(ByVal sender As Object, ByVal e As System.EventArgs)
Dim Email As Windows.Forms.TextBox = sender
If Email.Text <> "" Then
Dim rex As Match = Regex.Match(Trim(Email.Text), "^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*#([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,3})$", RegexOptions.IgnoreCase)
If rex.Success = False Then
MessageBox.Show("Please Enter a valid Email Address", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
Email.BackColor = Color.Red
Email.Focus()
Exit Sub
Else
Email.BackColor = Color.White
End If
End If
End Sub
End Module
Now use following code to Form Load Event like below.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
AssignValidation(Me.TextBox1, ValidationType.Only_Digits)
AssignValidation(Me.TextBox2, ValidationType.Only_Characters)
AssignValidation(Me.TextBox3, ValidationType.No_Blank)
AssignValidation(Me.TextBox4, ValidationType.Only_Email)
End Sub
Done..!
You must first validate if the input is actually an integer. You can do it with Integer.TryParse:
Dim intValue As Integer
If Integer.TryParse(TxtBox.Text, intValue) AndAlso intValue > 0 AndAlso intValue < 11 Then
MessageBox.Show("Thank You, your rating was " & TxtBox.Text)
Else
MessageBox.Show("Please Enter a Number from 1 to 10")
End If
Try this:
Private Sub txtCaseID_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtCaseID.KeyPress
If Not Char.IsNumber(e.KeyChar) AndAlso Not Char.IsControl(e.KeyChar) Then e.KeyChar = ""
End Sub
You could avoid any code by using a NumericUpDown control rather than a text box, this automatically only allows numbers and has a max and min.
It also allow accessing the number directly with NumericUpDown1.Value as well as using up and down arrows to set the number.
Also if a number higher/over the max is entered it will jump to the nearest allowed number.
Private Sub MyTextBox_KeyPress(sender As Object, e As System.Windows.Forms.KeyPressEventArgs) Handles MyTextBox.KeyPress
If Not IsNumeric(e.KeyChar) And Not e.KeyChar = ChrW(Keys.Back) Then
e.Handled = True
End If
End Sub
Private Sub textBox5_KeyPress(sender As System.Object, e As System.Windows.Forms.KeyPressEventArgs) Handles textBox5.KeyPress
If Asc(e.KeyChar) <> 8 Then
If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
e.Handled = True
End If
End If
End Sub
Private Sub Data_KeyPress(sender As Object, e As KeyPressEventArgs) Handles Data.KeyPress
If (Not e.KeyChar = ChrW(Keys.Back) And ("0123456789.").IndexOf(e.KeyChar) = -1) Or (e.KeyChar = "." And Data.Text.ToCharArray().Count(Function(c) c = ".") > 0) Then
e.Handled = True
End If
End Sub
Dim ch(10) As Char
Dim len As Integer
len = TextBox1.Text.Length
ch = TextBox1.Text.ToCharArray()
For i = 0 To len - 1
If Not IsNumeric(ch(i)) Then
MsgBox("Value you insert is not numeric")
End If
Next
If Not Char.IsNumber(e.KeyChar) AndAlso Not e.KeyChar = "." AndAlso Not Char.IsControl(e.KeyChar) Then
e.KeyChar = ""
End If
This allow you to use delete key and set decimal points
I know this post is old but I wanted to share something I have implemented to turn a TextBox into what I call an IntBox.
First you need to make an extension with:
<Runtime.CompilerServices.Extension()> _
Public Function HandledStringtoInteger(s As String) As Integer
Try
If s = String.Empty Then
Return 0
Else
Return Integer.Parse(s)
End If
Catch
Dim result As String = String.Empty
Dim ReturnInt As Integer
Dim Parsed As Integer
For Each Character In s.ToCharArray
If Character = "-" Then
If s.Substring(0, 1).ToString <> "-" Then
result = Character + result
End If
End If
If Character = "." Then
Exit For
End If
If Integer.TryParse(Character, Parsed) Then
result = result + Parsed.ToString
End If
Next
If result <> String.Empty Then
If Integer.TryParse(result, ReturnInt) Then
Return Integer.Parse(ReturnInt)
Else
If Double.Parse(result) > Double.Parse(Integer.MaxValue.ToString) Then
Return Integer.MaxValue
ElseIf Double.Parse(result) < Double.Parse(Integer.MinValue.ToString) Then
Return Integer.MinValue
Else
Return Integer.Parse(ReturnInt)
End If
End If
Else
Return 0
End If
End Try
End Function
Then make a TextChanged event sub:
Private Sub TextBox_to_IntBox(sender As Object, e As TextChangedEventArgs) Handles YourTextBox.TextChanged
If DirectCast(sender, TextBox).IsKeyboardFocused Then
DirectCast(sender, TextBox).Text = DirectCast(sender, TextBox).Text.HandledStringtoInteger
DirectCast(sender, TextBox).CaretIndex = DirectCast(sender, TextBox).Text.Length
End If
End Sub
Then whenever the user enters text it evaluates the string and only returns numeric values that are within the bounds of a standard Integer. With the "-" character you can change the integer from positive to negative and back again.
If anyone sees anything that can improve this code let me know but my tests show this works fantastic to make an IntBox.
EDIT:
I found another method that can work if you use properties in your code. (Note this will need a separate property per TextBox)
First create the property:
Public Class Properties
Implement INotifyPropertyChanged
Private _Variable as Integer
Public Property YourProperty as Object
get
Return _Variable
end get
set(value as Object)
_Variable = value.ToString.ToInteger 'I will give the ToInteger extension code later
end set
end property
Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Public Sub OnPropertyChange(ByVal e As PropertyChangedEventArgs)
If Not PropertyChangedEvent Is Nothing Then
RaiseEvent PropertyChanged(Me, e)
End If
End Sub
End Class
Then make the binding in your window's main class:
Public WithEvents _YourVariable as New Properties
Public Sub New()
InitializeComponent()
With YourTextBox
.SetBinding(Textbox.TextProperty, New Binding("YourProperty"))
.DataContext = _YourVariable
End With
End Sub
Finally here is the ToInteger Extension Code I set up:
''' <summary>
''' Handles conversion of variable to Integer.
''' </summary>
''' <param name="X"></param>
''' <param name="I">Returned if conversion fails.</param>
''' <returns>Signed 32bit Integer</returns>
''' <remarks></remarks>
<Runtime.CompilerServices.Extension()> _
Public Function toInteger(Of T)(ByRef X As T, Optional I As Integer = 0) As Integer
Dim S As String = X.ToString
Try
If S = String.Empty Then
Return I
Else
Return Integer.Parse(S)
End If
Catch
Dim result As String = String.Empty
Dim ReturnInt As Integer
Dim Parsed As Byte
For Each Character In S.ToCharArray
If Character = "-" Then
If S.Substring(0, 1).ToString <> "-" Then
result = Character + result
End If
End If
If Character = "." Then
Exit For
End If
If Byte.TryParse(Character, Parsed) Then
result = result + Parsed.ToString
End If
Next
If result <> String.Empty Then
If Integer.TryParse(result, ReturnInt) Then
Return Integer.Parse(ReturnInt)
Else
If Double.Parse(result) > Double.Parse(Integer.MaxValue.ToString) Then
Return Integer.MaxValue
ElseIf Double.Parse(result) < Double.Parse(Integer.MinValue.ToString) Then
Return Integer.MinValue
Else
Return Integer.Parse(ReturnInt)
End If
End If
Else
Return I
End If
End Try
End Function
With all these combined whenever they type something into the box it will act as if it were a textbox but when they change focus the ToInteger extension will set the value as an integer into the property and return it to the textbox.
Meaning that if the operator entered "-1w3" after focus changes it will return as "-13" automatically.
This may be too late, but for other new blood on VB out there, here's something simple.
First, in any case, unless your application would require, blocking user's key entry is somehow not a good thing to do, users may misinterpret the action as problem on the hardware keyboard and at the same time may not see where their keypreesed entry error came from.
Here's a simple one, let user's freely type their entry then trap the error later:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim theNumber As Integer
Dim theEntry As String = Trim(TextBox1.Text)
'This check if entry can be converted to
'numeric value from 0-10, if cannot return a negative value.
Try
theNumber = Convert.ToInt32(theEntry)
If theNumber < 0 Or theNumber > 10 Then theNumber = -1
Catch ex As Exception
theNumber = -1
End Try
'Trap for the valid and invalid numeric number
If theNumber < 0 Or theNumber > 10 Then
MsgBox("Invalid Entry, allows (0-10) only.")
'entry was invalid return cursor to entry box.
TextBox1.Focus()
Else
'Entry accepted:
' Continue process your thing here...
End If
End Sub
I have the solution where it will check whether the text is range 1 to 10 : [1-9] will check for the range from 1 to 9. I use one more condition to check for 10.
If txtBox.Text Like "[1-9]" Or txtBox.Text Like "10" Then
MessageBox.Show("true")
Else
MessageBox.Show("false")
End If
First of all set the TextBox's MaxLength to 2 that will limit the amount of text entry in your TextBox. Then you can try something like this using the KeyPress Event. Since you are using a 2 digit maximum (10) you will need to use a Key such as Enter to initiate the check.
Private Sub TextBox1_KeyPress(sender As System.Object, e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
Dim tb As TextBox = CType(sender, TextBox)
If Not IsNumeric(e.KeyChar) Then 'Check if Numeric
If Char.IsControl(e.KeyChar) Then 'If not Numeric Check if a Control
If e.KeyChar = ChrW(Keys.Enter) Then
If Val(tb.Text) > 10 Then 'Check Bounds
tb.Text = ""
ShowPassFail(False)
Else
ShowPassFail(True)
End If
e.Handled = True
End If
Exit Sub
End If
e.Handled = True
ShowPassFail(False)
End If
End Sub
Private Sub ShowPassFail(pass As Boolean)
If pass Then
MessageBox.Show("Thank you, your rating was " & TextBox1.Text)
Else
MessageBox.Show("Please Enter a Number from 1 to 10")
End If
TextBox1.Clear()
TextBox1.Focus()
End Sub
Public Function Isnumber(ByVal KCode As String) As Boolean
If Not Isnumeric(KCode) And KCode <> ChrW(Keys.Back) And KCode <> ChrW(Keys.Enter) And KCode <> "."c Then
MsgBox("Please Enter Numbers only", MsgBoxStyle.OkOnly)
End If
End Function
Private Sub txtBalance_KeyPress(ByVal sender As System.Object, ByVal e As
System.Windows.Forms.KeyPressEventArgs) Handles txtBalance.KeyPress
If Not Isnumber(e.KeyChar) Then
e.KeyChar = ""
End If
End Sub
This worked for me... just clear the textbox completely as non-numeric keys are pressed.
Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
If IsNumeric(TextBox2.Text) Then
'nada
Else
TextBox2.Clear()
End If
End Sub
Copy this function in any module inside your vb.net project.
Public Function MakeTextBoxNumeric(kcode As Integer, shift As Boolean) As Boolean
If kcode >= 96 And kcode <= 105 Then
ElseIf kcode >= 48 And kcode <= 57
If shift = True Then Return False
ElseIf kcode = 8 Or kcode = 107 Then
ElseIf kcode = 187 Then
If shift = False Then Return False
Else
Return False
End If
Return True
End Function
Then use this function inside your textbox_keydown event like below:
Private Sub txtboxNumeric_KeyDown(sender As Object, e As KeyEventArgs) Handles txtboxNumeric.KeyDown
If MakeTextBoxNumeric(e.KeyCode, e.Shift) = False Then e.SuppressKeyPress = True
End Sub
And yes. It works 100% :)
You can use the onkeydown Property of the TextBox for limiting its value to numbers only.
<asp:TextBox ID="TextBox1" runat="server" onkeydown = "return (!(event.keyCode>=65) && event.keyCode!=32);"></asp:TextBox>
!(keyCode>=65) check is for excludng Alphabets.
keyCode!=32 check is for excluding Space character inbetween the numbers.
If you want to exclude Symbols also from entering into the textbox, then include the below condition also in the 'onkeydown' property.
!(event.shiftKey && (event.keyCode >= 48 && event.keyCode <= 57))
Thus the TextBox will finally become
<asp:TextBox ID="TextBox1" runat="server" onkeydown = "return (!(event.keyCode>=65) && event.keyCode!=32 && !(event.shiftKey && (event.keyCode >= 48 && event.keyCode <= 57)));"></asp:TextBox>
Explanation:
KeyCode for 'a' is '65' and 'z' is '90'.
KeyCodes from '90' to '222' which are other symbols are also not needed.
KeyCode for 'Space' Key is '32' which is also not needed.
Then a combination of 'Shift' key and 'Number' keys (which denotes Symbols) also not needed. KeyCode for '0' is '48' and '9' is '57'.
Hence all these are included in the TextBox declaration itself which produces the desired result.
Try and see.
This was my final... It gets around all the type issues also:
Here is a simple textbox that requires a number:
public Sub textbox_memorytotal_TextChanged(sender As Object, e As EventArgs) Handles textbox_memorytotal.TextChanged
TextboxOnlyNumbers(sender)
End Sub
and here is the procedure that corrects all bad input:
Public Sub TextboxOnlyNumbers(ByRef objTxtBox As TextBox)
' ONLY allow numbers
If Not IsNumeric(objTxtBox.Text) Then
' Don't process things like too many backspaces
If objTxtBox.Text.Length > 0 Then
MsgBox("Numerical Values only!")
Try
' If something bad was entered delete the last character
objTxtBox.Text = objTxtBox.Text.Substring(0, objTxtBox.Text.Length - 1)
' Put the cursor and the END of the corrected number
objTxtBox.Select(objTxtBox.Text.Length + 1, 1)
Catch ex As Exception
End Try
End If
End If
End Sub
Use this in your Textbox Keydown event.
Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
'you can enter decimal "if nonNumberEntered(e, TextBox1, True) then"
'otherwise just numbers "if nonNumberEntered(e, TextBox1) then"
If nonNumberEntered(e, TextBox1, True) Then
e.SuppressKeyPress = True
End If
If e.KeyCode = Keys.Enter Then
'put your code here
End If
End Sub
Copy this function in any module inside your vb.net project.
Public Function nonNumberEntered(ByVal e As System.Windows.Forms.KeyEventArgs, _
ByVal ob As TextBox, _
Optional ByVal decim As Boolean = False) As Boolean
nonNumberEntered = False
If decim Then
' Determine whether the keystroke is a number from the top of the keyboard.
If e.KeyCode < Keys.D0 OrElse e.KeyCode > Keys.D9 Then
' Determine whether the keystroke is a number from the keypad.
If e.KeyCode < Keys.NumPad0 OrElse e.KeyCode > Keys.NumPad9 Then
If e.KeyCode <> Keys.Decimal And e.KeyCode <> Keys.OemPeriod Then
If e.KeyCode <> Keys.Divide And e.KeyCode <> Keys.OemQuestion Then
' Determine whether the keystroke is a backspace.
If e.KeyCode <> Keys.Back And e.KeyCode <> Keys.Delete _
And e.KeyCode <> Keys.Left And e.KeyCode <> Keys.Right Then
' A non-numerical keystroke was pressed.
nonNumberEntered = True
End If
ElseIf ob.Text.Contains("/") Or ob.Text.Length = 0 Then
nonNumberEntered = True
End If
ElseIf ob.Text.Contains(".") Or ob.Text.Length = 0 Then
nonNumberEntered = True
End If
End If
End If
Else
' Determine whether the keystroke is a number from the top of the keyboard.
If e.KeyCode < Keys.D0 OrElse e.KeyCode > Keys.D9 Then
' Determine whether the keystroke is a number from the keypad.
If e.KeyCode < Keys.NumPad0 OrElse e.KeyCode > Keys.NumPad9 Then
' Determine whether the keystroke is a backspace.
If e.KeyCode <> Keys.Back And e.KeyCode <> Keys.Delete _
And e.KeyCode <> Keys.Left And e.KeyCode <> Keys.Right Then
' A non-numerical keystroke was pressed.
nonNumberEntered = True
End If
End If
End If
End If
'If shift key was pressed, it's not a number.
If Control.ModifierKeys = Keys.Shift Then
nonNumberEntered = True
End If
End Function
This will allow numbers like 2/4 or numbers like 3.5 to be entered in your textbox if using decim "nonNumberEntered(e,Textbox1, True)".
Allows only numbers to be entered in textbox if using "nonNumberEntered(e,Textbox1, False)" or "nonNumberEntered(e,Textbox1)".
Edit: added text.
I had a similar use requirement recently for a TextBox which could only take numbers.
In the end I used a MaskedTextBox instead of a TextBox. You define a "mask" for the textbox and it will only accept characters which you have defined - in this case, numbers. The downside is that it leaves a bit of an ugly line within the TextBox;
What I loved about the MaskedTextBox was it was so customisable. If, for whatever reason you wanted a TextBox to only accept an input in the format of 3 ints followed by 2 letters, all you need to do is set the TextMask to 000LL. There are a load of pre-defined masks within Visual Studio, and the full documentation can be found here.
Now, I know this doesn't fully solve your issue, but the use of a MaskedTextBox takes away a huge part of the complexity of the problem. You can now guarantee that the contents of the MaskedTextBox will only ever be an Int, allowing you to run a simple If statement to ensure the value is =<10
I know this post is old but I want to share my code.
Private Sub txtbox1_TextChanged(sender As Object, e As EventArgs) Handles txtbox1.TextChanged
If txtbox1.Text.Length > 0 Then
If Not IsNumeric(txtbox1.Text) Then
Dim sel As Integer = txtbox1.SelectionStart
txtbox1.Text = txtbox1.Text.Remove(sel - 1, 1)
txtbox1.SelectionStart = sel - 1
End If
End If
End Sub
On each entry in textbox (event - Handles RestrictedTextBox.TextChanged), you can do a try to caste entered text into integer, if failure occurs, you just reset the value of the text in RestrictedTextBox to last valid entry (which gets constantly updating under the temp1 variable).
Here's how to go about it. In the sub that loads with the form (me.load or mybase.load), initialize temp1 to the default value of RestrictedTextBox.Text
Dim temp1 As Integer 'initialize temp1 default value, you should do this after the default value for RestrictedTextBox.Text was loaded.
If (RestrictedTextBox.Text = Nothing) Then
temp1 = Nothing
Else
Try
temp1 = CInt(RestrictedTextBox.Text)
Catch ex As Exception
temp1 = Nothing
End Try
End If
At any other point in form:
Private Sub textBox_TextChanged(sender As System.Object, e As System.EventArgs) Handles RestrictedTextBox.TextChanged
Try
temp1 = CInt(RestrictedTextBox.Text) 'If user inputs integer, this will succeed and temp will be updated
Catch ex As Exception
RestrictedTextBox.Text = temp1.ToString 'If user inputs non integer, textbox will be reverted to state the state it was in before the string entry
End Try
End Sub
The nice thing about this is that you can use this to restrict a textbox to any type you want: double, uint etc....
every text box has a validating and validated event you can use then as follows :-
Private Sub PriceTxt_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles PriceTxt.Validating
If Not IsNumeric(PriceTxt.Text) Then
PriceTxt.BackColor = Color.Red
MsgBox("The Price Should Be Numeric Only , Enter Again", vbCritical)
PriceTxt.Text = ""
PriceTxt.BackColor = Color.White
End If
End Sub
I know it's old.. I'll just leave this code here for the sake of convenience.
Integer only:
Public Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
With TextBox1
If IsNumeric(.Text) Then .Text = .Text.Select(Function(x) If(IsNumeric(x), x, "")) : .SelectionStart = .TextLength
End With
' etc..
End Sub
Accepts Double:
Public Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
With TextBox1
If IsNumeric(.Text) Then .Text = .Text.Select(Function(x) If(IsNumeric(x) Or x = ".", x, "")) : .SelectionStart = .TextLength
End With
' etc..
End Sub
Accepts basic operations + - * /, parentheses ( ) [ ] { } and Double:
Public Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
With TextBox1
If IsNumeric(.Text) Then .Text = .Text.Select(Function(x) If(IsNumeric(x) Or ".+-*/()[]{}".Contains(x), x, "")) : .SelectionStart = .TextLength
End With
' etc..
End Sub
You Can use Follow code Textbox Keypress Event:
Private Sub txtbox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtbox1.KeyPress
Try
If Val(txtbox1.text) < 10 Then
If Char.IsLetterOrDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
e.Handled = True
End If
Else
e.Handled = True
End If
Catch ex As Exception
ShowException(ex.Message, MESSAGEBOX_TITLE, ex)
End Try
End Sub
This code allow numbers only and you can enter only number between 1 to 10.
Very simple piece of code that works for me.
Private Sub Textbox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles textbox1.KeyPress
If Asc(e.KeyChar) > 58 Then
e.KeyChar = ""
End If
End Sub
Here's what works for me. It allows backspace, del, as well as numbers from the top row of the keyboard and the number pad. It excludes the + and - signs.
Private Sub tbMQTTPort_KeyDown(sender As Object, e As KeyEventArgs) Handles tbMQTTPort.KeyDown
Dim kc As New KeyConverter
Dim Regex = New Regex("[^0-9]+")
e.Handled = Regex.IsMatch(kc.ConvertToInvariantString(e.Key).Replace("NumPad", ""))
End Sub