C # Enter and paste numbers in the wpf winfrom control text box

Code

 Private void txtMachineCode_KeyDown (object sender, KeyEventArgs e)
{
TextBox txt = sender as TextBox;

// Shield illegal buttons
If (e. Key> = Key. NumPad0 & e. Key <= Key. NumPad9) | e. Key = Key. Decimal)
{
If (txt. Text. Contains (".") & e. Key = Key. Decimal)
{
E. Handled = true;
Return;
}
E. Handled = false;
}
Else if (e. key> = Key. d0 & e. key <= Key. d9) | e. key = Key. oemPeriod) & e. keyboardDevice. modifiers! = ModifierKeys. Shift)
{
If (txt. Text. Contains (".") & e. Key = Key. OemPeriod)
{
E. Handled = true;
Return;
}
E. Handled = false;
}
Else
{
E. Handled = true;
}
}
Private void txtMachineCode_TextChanged (object sender, TextChangedEventArgs e)
{
// Block Chinese Input and illegal character paste Input
TextBox textBox = sender as TextBox;
TextChange [] change = new TextChange [e. Changes. Count];
E. Changes. CopyTo (change, 0 );

Int offset = change [0]. Offset;
If (change [0]. AddedLength> 0)
{
Double num = 0;
If (! Double. TryParse (textBox. Text, out num ))
{
TextBox. Text = textBox. Text. Remove (offset, change [0]. AddedLength );
TextBox. Select (offset, 0 );
}
}
}