>>>I'm writing a WPF application using VS 2008 for a client that wants to force the users to scan a barcode for data entry into MOST textboxes. But they want a password protected override button on the form that will allow a person to manually enter the text if, for some reason, the barcode is unreadable or the reader is not working.
>>>
>>>Does anybody know of a way to ignore data entry into textboxes using the keyboard, but allow barcode scanned text?
>>
>>On the timing approach maybe something like this:

<Window x:Class="WpfApplication2.Window2"
>>    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
>>    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>>    Title="Window2" Height="300" Width="300">
>>    <DockPanel>
>>        <TextBox DockPanel.Dock="Top" x:Name="TB" KeyDown="TextBox_KeyDown"></TextBox>
>>        <TextBox DockPanel.Dock="Top" x:Name="RealBox" IsEnabled="False"></TextBox>
>>    </DockPanel>
>></Window>

Behind:

using System;
>>using System.Windows;
>>using System.Windows.Input;
>>
>>namespace WpfApplication2
>>{
>>    public partial class Window2 : Window
>>    {
>>        public Window2() {InitializeComponent(); }
>>
>>        private DateTime start;
>>        bool counting;
>>
>>        private void TextBox_KeyDown(object sender, KeyEventArgs e)
>>        {
>>            if (counting)
>>            {
>>                if (e.Key == Key.OemPlus)
>>                {
>>                    //End input
>>                    if (DateTime.Now < start.AddSeconds(2) && TB.Text.Length==6)
>>                    {
>>                        RealBox.Text = TB.Text + "+";
>>                    }
>>                    else
>>                        RealBox.Text = string.Empty;
>>                    counting = false;
>>                    TB.Text = string.Empty;
>>                    e.Handled = true;
>>                    return;
>>                }
>>            }
>>            if (!counting && e.Key == Key.OemPlus)
>>            {
>>                start = DateTime.Now;
>>                counting = true;
>>            }
>>        }
>>    }
>>}

Only input with a length of 6 characters and starting and ending with a + sign that is entered in less than 2 seconds will get into the 'RealBox'. Obviously you will need to reduce the time check in real life.
>
>Do you need to handle the case where someone inputs clipboard text via Ctrl-V or some other paste operation?

Probably need to do a lot of things before this would be usable in production (g)
Anyway, disabling the Paste command is simple enough. In XAML

<TextBox.InputBindings>
     <KeyBinding Command="ApplicationCommands.NotACommand"
               Key="V" Modifiers="Control" />
</TextBox.InputBindings>

or, more prettily, in code:

DataObject.AddPastingHandler(TB, (d, e) => { e.CancelCommand(); });