In VB.NET, how can I restrict the characters of a text box to numbers and control buttons only?

Question

In VB.NET, how can I restrict the characters of a text box to numbers and control buttons (i.e Delete, backspace...) only?

In other words, only 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, backspace and delete should be allowed

Answer 1

Use this event handler:

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
Dim c As Char
c = e.KeyChar
If Not (Char.IsDigit(c) Or Char.IsControl(c)) Then
e.Handled = True
End If
End Sub

Answer 2

Solution 1:
========
Use a MaskedTextBox and set the "mask" property to "9999999"

Try it and check if it behaves like you want (personally I don't like it)

Solution 2
=======
Or you could use an ordinary "TextBox" with the following handler to trap the TextChanged event and detect any non digit character

Dim oldText As String

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
Dim digitFound As Boolean
Dim textLength As Int16
Dim i As Int16

digitFound = True
textLength = TextBox1.Text.Length
i = 0
While (digitFound = True And i < textLength)
digitFound = Char.IsDigit(TextBox1.Text, i)
i = i + 1
End While
If digitFound = False Then
Dim caretPosition As Int16
caretPosition = TextBox1.SelectionStart
TextBox1.Text = oldText
TextBox1.SelectionStart = caretPosition - 1
Else
oldText = TextBox1.Text
End If
End Sub

Answer 3

Look into regular expressions. It will help you restrict whatever you want.

Answer 4

you need to use the masked text box

sorry i don't know what you should do for the other part