Hi, I want my my input, just numberic allowed.
if user key in alphabet, error message will show up.
How can i do that?!
Please help!

Thanks

IF IT IS RELATED TO A TEXT BOX:

Protected Sub TextBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

If IsNumeric(TextBox1.text) = false then

try
textbox1.text = textbox1.text.substring(0, len(textbox1.text) - 1)
catch ex as exception

textbox1.text = ""

end try

end if

    End Sub

If you generally want to capture a keyboard event (entire form, anywhere), you first need to on formload set:

KeyPreview = True

Then you do something like:

Private Sub Key_Click(ByVal sender as Object, ByVal e as System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown

if isnumeric(e.keydata.tostring) = false then


end if

End Sub

If this helped you, mark it as solved and/or give me some reputation points.

try this...
If Not IsNumeric(TextBox1.Text) Then
MessageBox.Show("Please enter Number")
End If

there are better to not allowed user to input alphabetic character. So, when user press keyboard keys, u can handled it by code to not allowed them to input alphabetical character.
this following code will not allowed you to input except number :

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        If (Microsoft.VisualBasic.Asc(e.KeyChar) < 48) _
              Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 57) Then
            e.Handled = True
        End If
        If (Microsoft.VisualBasic.Asc(e.KeyChar) = 8) Then
            e.Handled = False
        End If
    End Sub