"Bisley" <x> wrote in message news:eG**************@tk2msftngp13.phx.gbl...
I wish to restrict my textbox to only accepting numbers
I have looked the textbox KeyDown event and can inspect KeyEventArgs
parameter and interogate which key has been pressed, but I can't work out
how to stop then stop the character being added to the >text box
You can do this by creating your own textbox control that inherits from the
base: System.Windows.Forms.TextBox
and then you will have to override the method: WndProc to handle
WM_CHAR(=0x0102)..
a very simple example that you may extend is:
public class NumTextBox : System.Windows.Forms.TextBox
{
const int WM_CHAR = 0x0102;
private System.ComponentModel.Container components = null;
public NumTextBox()
{
// This call is required by the Windows.Forms Form Designer.
InitializeComponent();
// TODO: Add any initialization after the InitForm call
}
/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if(components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Component Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
components = new System.ComponentModel.Container();
}
#endregion
protected override void WndProc(ref Message m)
{
switch(m.Msg)
{
case WM_CHAR:
if( !char.IsDigit((char)m.WParam) )
{
if((char)m.WParam != 8)//backspace allowness.
{
return ;
}
}
break ;
}
base.WndProc(ref m);
}
}
