Hello,

i have a class 'MyTextBox' that derives from the default TextBox in Silverlight. This class currently contains no additional code.

I set up a binding in xaml to bind the Text-Property of MyTextbox to another Textbox to reflect the input made in the Textbox. The effect is that MyTextBox doesn´t update and not display the text of the other Textbox.

Additional i made an equal binding for a normal Textbox. And this works.

Here´s the XAML for the bindings.

<UserControl x:Class="Silverlight.Sample.Dummy"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:my="clr-namespace:Sample"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400">

<StackPanel x:Name="LayoutRoot" Background="White">
    <TextBox Height="23" x:Name="textBox2"  Width="120" />
    <TextBox Text="{Binding ElementName=textBox2, Path=Text, Mode=TwoWay}" Width="120" />
    <my:NumberTextBox Width="120" Text="{Binding ElementName=textBox2, Path=Text, Mode=OneWay}" />
</StackPanel>

Is there something special to set for binding, when i derive from a control.

PS: I tried a binding to a dummy object with INotifyPropertyChanged and set it as DataContext for the existing Textboxes. This test works as expected and my derived textbox gets updated.