Custom Textbox with WPF Dependency Property

In this blog you will learn how to create Custom Textbox with WPF Dependency Property.

It will create a custom Textbox in WPF that will not allow space while typing. It will be created with the help of WPF Dependency property.

Step 1

Take a class and inherit it from “TextBox” class:

public class ValidatedTextBox : TextBox
{
   public ValidatedTextBox()
   {

   }/ <summary>
   /// Dependency property to get/set flag for allowing space character
   /// </summary>
   public static readonly DependencyProperty IsSpaceAllowedProperty =
   DependencyProperty.Register("IsSpaceAllowed", typeof(bool),     typeof(ValidatedTextBox));
   public bool IsSpaceAllowed
   {
       get
       {
            return (bool)base.GetValue(IsSpaceAllowedProperty);
       }
       set
       {
            base.SetValue(IsSpaceAllowedProperty, value);
       }
   }
   protected override void OnPreviewKeyDown(KeyEventArgs e)
   {
         base.OnPreviewKeyDown(e);
         if (!IsSpaceAllowed && (e.Key == Key.Space))
         {
              e.Handled = true;
         }
    }
 }

Step 2

Now, Use this in the .XAML file:

Add namespace of ValidatedTextBox.cs class file in .XAML like below:

xmlns:CustomControls="clr-namespace: ValidatedTextBox;assembly= ValidatedTextBox "

Now, Use it like below:

<CustomControls:ValidatedTextBox IsSpaceAllowed="False"
 x:Name="MyTextBox" />

It will not allow space into the textbox.