How can I use numeric values only but also allow the Backspace?

[Alkis Arxontas]

I am using Visual Basic Express 2008.
I have added the following code to my text box:

Private Sub TextBox1_KeyPre ss(ByVal sender As Object, ByVal e As System.Windows. Forms.KeyPressE ventArgs) Handles TextBox1.KeyPre ss
If Not IsNumeric(e.Key Char) Then
MessageBox.Show ("Please insert numbers only.", "Error!", MessageBoxButto ns.OK, MessageBoxIcon. Exclamation)
e.KeyChar = Nothing
End If
End Sub

The problem is that if I click Backspace it shows the same error and I can't change a type error. Is there a way to get it working?

[VijaySofist]

Hi,

You can try the following Code

'Add This Function to your Code
Public Shared Sub ValidateKeys(ByVal strContent As String, ByVal e As System.Windows.Forms.KeyPressEventArgs, ByVal blnAlpha As Boolean, ByVal blnNumeric As Boolean, ByVal blnSpecial As Boolean, Optional ByVal strAllowableChars As String = "", Optional ByVal strDisAllowableChars As String = "", Optional ByVal blnToUpperCase As Boolean = True)
        Dim KeyAscii As Integer
        Dim intCounter As Integer
        Dim EnteredKeyAscii As Integer
        Dim mValidCharacters As String = ""
        Try
            If e.KeyChar = "'" Then
                e.KeyChar = CChar("".ToString)
                Exit Sub
            End If

            KeyAscii = Asc(e.KeyChar)
            EnteredKeyAscii = Asc(e.KeyChar)

            If blnNumeric = True And blnAlpha = False And blnSpecial = True And strAllowableChars = "." And strDisAllowableChars = "" Then
                If e.KeyChar = "." Then
                    If strContent.IndexOf(".") >= 0 Or strContent.Length.Equals(0) Then 'if period already exists or if the user has entered period as the first entry
                        e.KeyChar = CChar("".ToString)
                        Exit Sub
                    End If
                End If
            End If

            If blnToUpperCase = True Then KeyAscii = KeyAscii - CInt(IIf(KeyAscii >= 97 And KeyAscii <= 122, 32, 0))

            If blnAlpha = True Then
                For intCounter = Asc("A") To Asc("Z")
                    mValidCharacters = mValidCharacters & UCase(Chr(intCounter))
                Next
            End If

            If blnNumeric = True Then
                For intCounter = 0 To 9
                    mValidCharacters = mValidCharacters & intCounter
                Next
            End If

            If blnSpecial = True Then
                If strAllowableChars <> "" And strDisAllowableChars <> "" Then
                    mValidCharacters = mValidCharacters & strAllowableChars
                ElseIf strAllowableChars <> "" And strDisAllowableChars = "" Then
                    mValidCharacters = mValidCharacters & strAllowableChars
                ElseIf strAllowableChars = "" And strDisAllowableChars <> "" Then
                    For intCounter = 1 To 255
                        If Not InStr(1, strDisAllowableChars, Chr(intCounter), vbTextCompare) > 0 Then
                            mValidCharacters = mValidCharacters & Chr(intCounter)
                        End If
                    Next
                ElseIf strAllowableChars = "" And strDisAllowableChars = "" Then
                    For intCounter = 1 To 255
                        mValidCharacters = mValidCharacters & Chr(intCounter)
                    Next
                End If
            End If

            If Not (InStr(1, mValidCharacters, Chr(KeyAscii).ToString, CompareMethod.Text)) = 0 Or KeyAscii = 8 Then
                e.KeyChar = Chr(KeyAscii)
            Else
                e.KeyChar = CChar("".ToString)
            End If
        Catch excp As Exception
            MsgBox(excp.Message)
        End Try
    End Sub

'How to use - Example
ValidateKeys(txtEmpID.Text, e, False, True, False)

Regards
Vijay.R

[Alkis Arxontas]

Wow :) Actually thanks a lot for the code!! But the only things I'd like to be available to insert should be 0123456789 Backspace Delete
Could you help me on how to do that?