Complete noob to vb.net (and programming in general) here, all I really want is every time I click a button, the number in the textbox is added by 1 but the new number shows up on the next line. Tried to google this a hundred times but nothing really helped.
I don't want to use loops as I don't want all numbers to show up at once, only for the added number to show up after clicking a specific button (on a new line).
Public Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim txtoutput As String = ""
Dim a As Integer = 1
txtoutput &= "the value of a =" & a & Environment.NewLine
a = a + 1
TextBox1.Text = txtoutput
End Sub
You are replacing the Text, you want to append a new line, so you need to do:
Private a As Int32 = 0
Public Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
a += 1
Dim newLine = $"the value of a = {a}"
TextBox1.Text = TextBox1.Text & Environment.NewLine & newLine
End Sub
You also have to use a field and not a local variable if you want to retain the old value and increment it. Otherwise it is reset always to it's inital value.
Please try to change dim a to static a
Public Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim txtoutput As String = ""
Static a As Integer = 1
txtoutput &= "the value of a =" & a & Environment.NewLine
a = a + 1
TextBox1.Text = txtoutput
End Sub
Related
sorry I'm a newbie and I'm trying to write a program to get ten integers from user with a an Inputbox or Textbox and displays the biggest and lowest one in a label with visual basic. I'll be appreciated if you help me out with this.
Thank you. this is my solution. I don't know how to compare these ten numbers with each other.
Private Sub btnShow_Click(sender As Object, e As EventArgs) Handles btnShow.Click
Dim i, Container, Max, Numbers
Max = 0
i = 1
While (i <= 10)
Numbers = InputBox("please enter a number", "Enter a number")
Max = Numbers
Container = Container & " " & Numbers
i = i + 1
End While
lblresult.Text = Container
End Sub
conceptually speaking you should use a List(Of Integer) or List(Of Double), perform the loop 10 times adding the value into the list.
Suppose this is our list
Dim container As New List(Of Integer)
To get input
Dim userInput = ""
Dim input As Integer
userInput = InputBox("please enter a number", "Enter a number")
If Integer.TryParse(userInput, input) Then
container.Add(input)
End If
After the loop
Console.WriteLine($"Min: {container.Min()} Max: {container.Max()}")
Does this make sense to you ?
Edit, based on asking for Windows Forms example.
You could do the following instead of a InputBox, requires a label, a button and a TextBox.
Public Class MainForm
Private container As New List(Of Integer)
Private Sub CurrentInputTextBox_KeyPress(sender As Object, e As KeyPressEventArgs) _
Handles CurrentInputTextBox.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 Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
CurrentLabel.Text = "Enter number 1"
End Sub
Private Sub ContinueButton_Click(sender As Object, e As EventArgs) _
Handles ContinueButton.Click
If Not String.IsNullOrWhiteSpace(CurrentInputTextBox.Text) Then
container.Add(CInt(CurrentInputTextBox.Text))
CurrentLabel.Text = $"Enter number {container.Count + 1}"
If container.Count = 10 Then
ContinueButton.Enabled = False
CurrentLabel.Text =
$"Count: {container.Count} " &
$"Max: {container.Max()} " &
$"Min: {container.Min()}"
Else
ActiveControl = CurrentInputTextBox
CurrentInputTextBox.Text = ""
End If
End If
End Sub
End Class
I really didn't want to do your homework for you but I was afraid you might be hopelesly confused.
First let's go over your code. See comments
Private Sub btnShow_Click(sender As Object, e As EventArgs) Handles btnShow.Click
Dim i, Container, Max, Numbers 'Don't declare variables without an As clause
Max = 0 'Max is an object
i = 1 'i is and object
While i <= 10 'the parenthesis are unnecessary. You can't use <= 2 with an object
Numbers = InputBox("please enter a number", "Enter a number")
Max = Numbers
Container = Container & " " & Numbers 'Container is an object; you can't use & with an object
i = i + 1 'Again with the object i can't use +
End While
lblresult.Text = Container
End Sub
Now my approach.
I created a List(Of T) at the Form level so it can be seen from different procedures. The T stands for type. I could be a built in type or type you create by creating a Class.
The first click event fills the list with the inputted numbers. I used .TryParse to test if the input is a correct value. The first parameter is a string; the input from the user. The second parameter is a variable to hold the converted string. .TryParse is very clever. It returns True or False base on whether the input string can be converted to the correct type and it fills the second parameter with the converted value.
The second click event loops through the list building a string to display in Label1. Then we use methods available to List(Of T) to get the numbers you desire.
Private NumbersList As New List(Of Integer)
Private Sub FillNumberList_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Integer
While i < 10
Dim input = InputBox("Please enter a whole number")
Dim inputInt As Integer
If Integer.TryParse(input, inputInt) Then
NumbersList.Add(inputInt)
i += 1 'We only increment i if the parse is succesful
End If
End While
MessageBox.Show("Finished Input")
End Sub
Private Sub DisplayResults_Click(sender As Object, e As EventArgs) Handles Button2.Click
Label1.Text = "You input these numbers "
For Each num In NumbersList
Label1.Text &= $"{num}, "
Next
Label2.Text = $"The largest number is {NumbersList.Max}"
Label3.Text = $"The smallest number is {NumbersList.Min}"
End Sub
For example i got two barcode, so i scan the two barcode at the textbox, it appear AVM12323AVM44454..
But I want it to be displayed in textbox for example like AVM12323, AVM44454. where there is a "," comma between the two code.
Previously i'm only tested for scan one barcode only in the textbox. So now i'm trying to scan more than one barcode in one textbox.
i have been looking the few example but not success.
Private Sub TextBoxMulti_TextChanged(sender As Object, e As EventArgs) Handles TextBoxMulti.TextChanged
Dim selectedMultiArrayScan As String()
Dim selectedMultiScan As String = ""
selectedMultiScan = TextBoxMulti.Text & ","
selectedMultiArrayScan = selectedMultiScan.Split(",")
End Sub
Private Sub MultiScan_Click(sender As Object, e As EventArgs) Handles MultiScan.Click
For Each stateName As String In selectedMultiArrayScan
//some query for each scanned item
Next stateName
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Timer1.Enabled = False ' Fire only once
If TextBox1.Text.Trim <> "" Then TextBox1.Text += ", "
End Sub
Private Sub TextBox1_KeyUp(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyUp
Timer1.Enabled = True
End Sub
Read the textbox with the event TextChanged like this:
If TextBox1.Text.Length >3 Then
Dim txt As String = Label1.Text + ", " + TextBox1.Text
If txt.Length = 6 Then txt = txt.Remove(0, 2)
Label1.Text = txt
'if you want to erase the text in TextBox1
TextBox1.SelectionStart = 0
TextBox1.SelectionLength = Label1.Text.Length
Try
End If
I use this code and it show the Barcodes in a label, you can replace the label to show in the textBox. Also, my Barcodes lenght always have 4 Alphanumeric characters. For you, Replace the If TextBox1.Text.Length >3 Then (3 to 8) to detect where a Barcode is readed.
I'm trying to make a simple auto typer in Visual Basic. I want it to take the ListBox items and output at the user's choice of interval.
The problem is I don't know how to make the Timer's Tick event send each line and restart at the top of the list and continue to loop this way.
Form Design:
I have not listed much code because there really isn't much to list yet.
Private Sub intervalTimer_Tick(sender As Object, e As EventArgs) Handles intervalTimer.Tick
End Sub
Here is a code, but you need to replaced the ListBox with a ListView, it is the same look, this is just for the code to work.
This code is going to take each line from the ListView and output it using MsgBox using a timer that has an interval of user's choice, just remove the message box and output the result where ever you need, and you're all good :
First define this variable in your public class :
Dim ListedItems As String
Here is when you press the set button to set the interval :
Try
intervalTimer.Interval = intervalTextBox1.Text * 1000
Catch
MsgBox("The interval must be in purly seconds only!")
End Try
Here is when you press the start button :
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
For Each LVI As ListViewItem In ListView1.Items
If ListedItems = "" Then
ListedItems = LVI.Text
Else
ListedItems &= vbLf & LVI.Text
End If
Next
Timer1.Start()
End Sub
Here is when the timer tick event :
Private Sub intervalTimer_Tick(sender As Object, e As EventArgs) Handles intervalTimer.Tick
intervalTimer.Stop()
Dim SeprateLine As String
Dim Separator As Integer
If ListedItems.Contains(vbLf) Then
Separator = ListedItems.IndexOf(vbLf)
SeprateLine = ListedItems.Remove(Separator)
ListedItems = ListedItems.Substring(Separator + 1)
Else
SeprateLine = ListedItems
ListedItems = ""
End If
MsgBox(SeprateLine)
If ListedItems <> "" Then
intervalTimer.Start()
End If
End Sub
Finally i hope that this will help you with what you need :)
I was wondering if you could help me? My question is that, is there a way of changing the value in my.Settings in a form if you enter a number/decimal in a textbox and click a button and then update in the settings to be then changed in another from which is linked to my.Settings in a variable?!
Form 1:
Public Class frmConverter
Dim input As String
Dim result As Decimal
Dim EUR_Rate As Decimal = My.Settings.EUR_Rates
Dim USD_Rate As Decimal = 1.6
Dim JYP_Rate As Decimal = 179.65
Private Sub btnCalc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalc.Click
input = txtInput.Text
Try
If ComboBox1.Text = "£" Then
Pounds()
ElseIf ComboBox1.Text = "€" Then
Euros()
ElseIf ComboBox1.Text = "$" Then
Dollars()
ElseIf ComboBox1.Text = "¥" Then
Yen()
End If
Catch es As Exception
MsgBox("Error!")
End Try
End Sub
Private Sub btnSettings_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSettings.Click
Me.Hide()
frmExchange.Show()
End Sub
Private Sub btnReset_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReset.Click
txtInput.Text = ""
lblResult.Text = ""
End Sub
Function Pounds()
If ComboBox1.Text = "£" And ComboBox2.Text = "€" Then
result = (input * EUR_Rate)
lblResult.Text = FormatNumber(result, 2) & " " & ComboBox2.Text
ElseIf ComboBox1.Text = "£" And ComboBox2.Text = "$" Then
result = (input * USD_Rate)
lblResult.Text = FormatNumber(result, 2) & " " & ComboBox2.Text
ElseIf ComboBox1.Text = "£" And ComboBox2.Text = "¥" Then
result = (input * JYP_Rate)
lblResult.Text = FormatNumber(result, 2) & " " & ComboBox2.Text
End If
Return 0
End Function
Form 2:
Public Class frmExchange
Private Sub frmExchange_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
My.Settings.EUR_Rates = (txtinput.Text)
My.Settings.Save()
My.Settings.Reload()
End Sub
Public Sub SetNewRate(ByVal rate As Decimal)
txtinput.Text = rate.ToString
End Sub
Private Sub btnchange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnchange.Click
If ComboBox1.Text = "€" Then
My.Settings.USD_Rates = (txtinput.Text)
frmConverter.SetNewRate(txtinput.Text)
End If
End Sub
End class
It sounds like you are trying to use My.Settings as some sort of set of global reference variables. Thats not what they are for, not how they work and not what they are.
First, turn on Option Strict as it looks like it may be Off. This will store the decimal value of a textbox to a Settings variable which is defined as a Decimal:
My.Settings.USD_Rates = CDec(SomeTextBox.Text)
Thats all it will do. It wont save the value and it wont pass it around or share it with other forms and variables.
My.Settings.Save 'saves current settings to disk for next time
My.Settings.Reload 'Load settings from last time
This is all covered on MSDN. There is no linkage anywhere. If you have code in another form like this:
txtRate.Text = My.Settings.USD_Rates.ToString
txtRate will not automatically update when you post a new value to Settings. There are just values not Objects (see Value Types and Reference Types). To pass the new value to another form:
' in other form:
Public Sub SetNewRate(rate As Decimal)
' use the new value:
soemTextBox.Text = rate.ToString
End Sub
in form which gets the change:
Private Sub btnchangeRate(....
' save to settings which has nothing to do with passing the data
My.Settings.USD_Rates = CDec(RateTextBox.Text)
otherForm.SetNewRate(CDec(RateTextBox.Text))
End Sub
You may run into problems if you are using the default form instance, but that is a different problem.
You botched the instructions. The 2 procedures are supposed to go in 2 different forms - one to SEND the new value, one to RECEIVE the new value. With the edit and more complete picture, there is an easier way.
Private Sub btnSettings_Click(...) Handles btnSettings.Click
' rather than EMULATE a dialog, lets DO a dialog:
'Me.Hide()
'frmExchange.Show()
Using frm As New frmExchange ' the proper way to use a form
frm.ShowDialog
' Im guessing 'result' is the xchg rate var
result = CDec(frm.txtInput.Text)
End Using ' dispose of form, release resources
End Sub
In the other form
Private Sub btnchange_Click(....)
' do the normal stuff with Settings, if needed then:
Me.Hide
End Sub
hello i want to read text file line by line and set every lien in textbox eash time i click the button
this is my code and working fine. but i looking for easy way to read large text that has more thean 5 lines ?
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Static count As Integer
count = count + 1
Dim textfile As String = "c:\test.txt"
If IO.File.Exists(textfile) Then
Dim readLines() As String = IO.File.ReadAllLines(myFile)
If count = 1 Then
TextBox1.Text = readLines(0)
End If
If count = 2 Then
TextBox1.Text = readLines(1)
End If
If count = 3 Then
TextBox1.Text = readLines(2)
End If
If count = 4 Then
TextBox1.Text = readLines(3)
End If
If count = 5 Then
TextBox1.Text = readLines(4)
End If
If count = 6 Then
TextBox1.Text = readLines(5)
End If
End If
End Sub
I think you need to read the file just one time when you load your form (assuming a WinForms example here)
' Declare these two globally
Dim readLines() As String
Dim count As Integer = 0
Private void Form_Load(sender As Oject, e As EventArgs) Handles Base.Load
' In form load, read the file, just one time
Dim textfile As String = "c:\test.txt"
If IO.File.Exists(textfile) Then
readLines() As String = IO.File.ReadAllLines(myFile)
else
TextBox1.Text "File not found"
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
' Check if you have a file and if you don't have reached the last line
if readLines IsNot Nothing AndAlso count < readLines.Length Then
TextBox1.Text = readLines(count)
count += 1
else
TextBox1.Text "End of file"
End If
End Sub
This reduces the amount of code you need to write:
TextBox1.Text = readLines(count - 1)