The first letter of the entered text should be alphabet only and special characters should not be allowed. I am doing project using vb.net. may I know how to do this.
Following accepts only Characters in TextBox:
Try this code, it will check if the text in your textbox matches the pattern in the []-brackets (^ will check the first character, A-Z will only allow uppercase characters):
Example 1:
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
Dim textBox As TextBox
textBox = sender
If (textBox.Text.Length > 0) Then
If Not Regex.IsMatch(textBox.Text, "^[A-Z|a-z]") then
TextBox1.Text = String.Empty
End If
End If
End Sub
Example 2:
Dim Name As String = txtBox.text
If Not Name.Chars(0).IsLetter(Name.Chars(0)) Then
MessageBox.Show("Not valid!")
txtBox.clear()
txtBox.focus()
End If
Please make changes as per your requirement.
Take a look at the String functions: http://msdn.microsoft.com/en-us/library/dd789093.aspx
You might also want to have a look at Regular Expressions: http://msdn.microsoft.com/en-us/library/hs600312(v=vs.110).aspx
Related
I am writing some code in VB.Net to subtract one string from another string, but this is not working. in output nothing is changed in the target string. But there is no error message. Please help. Thanks.
If RadioButton1.Checked Then
TextBox1.Text = ""
positive = (TextBoxp1.Text + TextBoxp2.Text + TextBoxp3.Text)
negative = (TextBoxn1.Text + TextBoxn2.Text + TextBoxn3.Text)
findstring = Replace(positive, negative, "")
TextBox1.Text = findstring
End If
The concatenation symbol in vb.net is the ampersand (&). You may get unexpected results it you use the plus sign and the strings contain numbers. Parenthesis are not necessary to evaluate an expression except to establish order of calculation when it conflicts with order of precedence.
You are using the vb.net Strings.Replace method. I would use the .net String.Replace method because it is easier to move between .net languages when you get used to using .net methods instead of vb specific methods.
This method takes the original string in this case negative and looks for the entire positive string. If it finds the entire string it replaces it with the empty string.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim positive = "b" & "cd" & "ef"
Dim negative = "abc" & "def" & "ghi"
TextBox1.Text = negative.Replace(positive, "")
'Result is aghi
End Sub
If you are trying to remove individual letters from a string then you will have to use a loop. Luckily for us a String is an array of Char.
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim positive = "ceg"
Dim negative = "abcdefg"
For Each ch As Char In positive
negative = negative.Replace(ch, "")
Next
TextBox1.Text = negative
'Result abdf
End Sub
You are making this way too complicated. If what you want is to remove a substring from within a string use replace like this:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btnRemove.Click
If rdbtnRemove.Checked Then
txtResultString.Text = Replace(txtLargeString.Text, txtSearchString.Text, "")
End If
End Sub
All you need is two radio buttons, three text boxes and a button. If you enter 1121221114141 in the txtLargeString text box, 2122 in the txtSearchString text box and execute the code, the result is 111114141 which is the result of removing the txtSearchString input from the txtLargeString input.
Or if as #Mary suggested you want to use the more modern version of replace use this code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btnRemove.Click
If rdbtnRemove.Checked Then
txtResultString.Text = txtLargeString.Text.Replace(txtSearchString.Text, "")
End If
End Sub
Good day!
I want to add some strings from a barcode scanner, captured in a text box, to a list box, and, before adding it, to check if the specific string hasn't been already added. So I have a text box called txtWO which captures what the reader scans and a list box called lstScanBOM to which I add the text box string if the item is not already added. The problem is, that whatever I do, only after the specific string is added twice the checking for duplicate entry starts to work. In other words I scan the same string twice, it added it, and then when I scan the third time only it throws the message with the error saying it is a duplicate. I don't understand why is doing this. The code is below:
Private Sub frmValidareFIP_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If txtWO.Focused = False Then
txtWO.Select()
End If
End Sub
Private Sub AddUnique(StringToAdd As String)
If lstScanBom.Items.Contains(StringToAdd) = True Then
MsgBox("Articol duplicat!", vbOKOnly)
Else
'it does not exist, so add it..
lstScanBom.Items.Add(StringToAdd)
End If
End Sub
Private Sub txtWO_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
barcode = txtWO.Text
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
IMO Try listing the data outside of the ListBox. I can't see why it isn't working, maybe we need a third pair of eyes to see it!?
Try adding a list (of string) as a Private within the form, populate this as your user scans, and check the duplicate there..
This is definately not the best solution, but I'm sure it will help!
Private List_Barcodes As List(Of String)
Private Sub frmValidareFIP_Load(sender As Object, e As EventArgs) Handles MyBase.Load
List_Barcodes = New List(Of String)
'You can also populate this list on load, if you have a stored cahce of previous scanned barcodes?
'List_Barcodes.Add("0123456")
'List_Barcodes.Add("4567890")
'...etc
If txtWO.Focused = False Then
txtWO.Select()
End If
End Sub
Private Sub AddUnique(StringToAdd As String)
If List_Barcodes.Contains(StringToAdd) Then
MsgBox("Articol duplicat!", vbOKOnly)
Else
'Place into dynamic list
List_Barcodes.Add(StringToAdd)
'and Place into your listbox
lstScanBom.Items.Add(StringToAdd)
End If
End Sub
Private Sub txtWO_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
barcode = txtWO.Text
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
Your barcode reader is returning <carriage return><line feed> as enter. Your code catches the enter key (carriage return = 13), but leaves the line feed (10) character. So the next time you scan something it will start with a line feed. The two strings in your example are different because the first is "58335001" and the second is "<line feed>58335001". The third one is "<line feed>58335001", which is a duplicate of the second.
One way to fix this is to trim your string.
Private Sub txtWO_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
'Add the .Trim() to remove the leading <line feed> character
barcode = txtWO.Text.Trim()
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
The most simple decision is ONLY to make your textBox control txtWO NOT multiline
And that's enough! Your code will work correctly!
I'm writing an article rewriter in VB.NET and I am having a problem in replacing some words with another word.
is there a way i can replace the words directly while the user is typing.
while texting it , i typed "what is love, we always look at it"
and it displayed what is love we frequently look at it
instead of
what is affection we frequently see it
Here is my code:
Private Sub RichTextBox1_TextChanged(sender As Object, e As EventArgs) Handles RichTextBox1.TextChanged
If RichTextBox1.Text.Contains("always") Then
RichTextBox2.Text = RichTextBox1.Text.Replace("always", "frequently")
End If
If RichTextBox1.Text.Contains("love") Then
RichTextBox2.Text = RichTextBox1.Text.Replace("love", "affection")
End If
If RichTextBox1.Text.Contains("look") Then
RichTextBox2.Text = RichTextBox1.Text.Replace("look", "see")
End If 'RichTextBox2.Text = RichTextBox1.Text
End Sub
If I understand the problem correctly, you want to change the text as it's being typed in. You don't want to use the text changed event as it won't occur immediately on typing. Use the keyup event instead.
Private Sub RichTextBox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles RichTextBox1.KeyUp
Dim wordToFind As String = "findword"
Dim replaceWord As String = "replaceword"
Richtextbox2.rtf = RichTextBox1.replace(wordToFind, replaceWord)
End If
End Sub
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
OpenFileDialog1.ShowDialog()
End Sub
Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
Dim reader As New IO.StreamReader(OpenFileDialog1.FileName)
TextBox1.Text = reader.ReadToEnd
End Sub
End Class
the program will be like this when press open the open file diloge well open the file from the computer and the well show in textbox1 . what I want to do is to send xvalue(the number after(x)) is send to textbox(x) and send yvalue(the number after(y)) is send to textbox(y) and each letter value well send value (number) well send like this and this code is for open the file I think the array must used in this case but I dont know how use the arry
If I've understood you correctly, I think the following will work:
Dim input As String="N14G73X315.2Y83.7I40.0J6.4A0.0H3K75T11F5M0C0.0"
Dim matches = System.Text.RegularExpressions.Regex.Matches(input, "\w[0-9.]+")
Dim parts = Matches.Cast(Of System.Text.RegularExpressions.Match).Select(Function(p) New With {.Key=p.Value.Substring(0,1), .Value=p.Value.Substring(1)}).ToDictionary(Function(p) p.Key, Function(p) p.Value)
txtX.text = parts("X")
txtY.text = parts("Y")
etc
We use a regular expression to split the string into groups of a single letter followed by a number including an optional decimal point. We then use Linq to turn this into a dictionary of numbers (well string representations of numbers) keyed on their corresponding letter from the input. You can then pull these from the dictionary to set each text field
You could also use capture groups on the regular expression instead of splitting the output in the linq statement
I have a TextBox, which has a CheckBox operation to mask the containing text. This works with the following code:
Private Sub CheckBox2_Checked(ByVal sender As Object, ByVal e As EventArgs) Handles CheckBox2.CheckedChanged
TextBox14.PasswordChar = "*"
End Sub
It works well, but I want to also be able to uncheck theCheckBox and then have the recognizable text return. How can I achieve this?
The docos actually state:
The character used to mask characters entered in a single-line TextBox
control. Set the value of this property to 0 (character value) if you
do not want the control to mask characters as they are typed. Equals 0
(character value) by default.
Found here: http://msdn.microsoft.com/en-us/library/system.windows.forms.textbox.passwordchar(v=vs.110).aspx
In VB.NET, that would be easiest done by setting PasswordChar to vbNullChar.
You can do so by simply setting the PasswordChar property back to a null character, like this:
Private Sub CheckBox2_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) Handles CheckBox2.CheckedChanged
If CheckBox2.Checked Then
TextBox14.PasswordChar = "*"c
Else
TextBox14.PasswordChar = ControlChars.NullChar
End If
End Sub
The CheckedChanged event occurs every time the Checked property changes. So, when the user unchecks the CheckBox, it will raise that event too, so you need to check to see whether or not the control is currently checked.
I found just toggling the password character wasn't enough. In my case I was masking a connection string. With the lack of spaces in my text I had an issue going back and forth. My text would be cut off and wasn't wrapping properly.
Private Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs)
Dim beforeText As String = TextBox1.Text
TextBox1.Text = ""
TextBox1.PasswordChar = IIf(CheckBox1.Checked, Convert.ToChar(0), "*"c)
TextBox1.Text = beforeText
End Sub
I imagine if you used a font like Console this would not be a problem as all character widths are constant.