How do I Raise an Event when the Binding is completed?

I have a TextBox in my application that i am developing and the binding is done in the xaml

I want to be able to raise an event when the binding of the TextBox Text Property is completed meaning when the text is loaded/changed through binding into the TextBox how do i achive this?

I tried TextChanged Event also Loaded Event but no luck right after the Binding is complected so how do i do it?

<ListBox x:Name="listBoxCategories" Background="Transparent" BorderThickness="0" Grid.Row="4" Grid.ColumnSpan="2" Margin="0" Padding="0" ItemContainerStyle="{StaticResource ListBoxItemStyle}" ItemsSource="{Binding ElementName=discussion_categoryDomainDataSource, Path=Data}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPa开发者_JAVA百科nel x:Name="stackPanelCategory" Orientation="Vertical" Margin="0" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                        <TextBlock x:Name="TextBlockCategoryId" Text="{Binding Path=CategoryID}" />
                        <toolkit:Expander IsExpanded="True" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Style="{StaticResource ForumExpanderStyleRight}">
                            <toolkit:Expander.Header>
                                <TextBlock FontSize="16" FontWeight="Bold" Foreground="White" Margin="4,0,4,0" Text="{Binding CategoryName}" LayoutUpdated="TextBlock_LayoutUpdated" />
                            </toolkit:Expander.Header>
                            <ListBox x:Name="listBoxBoards" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Background="Transparent" BorderThickness="0" Margin="0" Padding="0" ItemContainerStyle="{StaticResource ListBoxItemStyle}" ItemsSource="{Binding CategoryBoards}">
                                <ListBox.ItemTemplate>
                                    <DataTemplate>
                                        <Grid Margin="0" HorizontalAlignment="Stretch" x:Name="GridBoard">
                                        </Grid>
                                    </DataTemplate>
                                </ListBox.ItemTemplate>
                            </ListBox>
                        </toolkit:Expander>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

at this line

<TextBlock x:Name="TextBlockCategoryId" Text="{Binding Path=CategoryID}" />

I want an event where when the Binding is completed i want to give a different data source for the list box under the parent stack panel so i need the binding event so when i have the catedory id int he text block which later will be hidden in the xaml ( which now is not collapsed for testing reasons )

This is a slightly peculiar thing to want to do, it might help if you tell us why you are wanting to do this?

However, with no other information to hand, I will propose a solution.

If the TextBox API events do not provide the infomation you need, try handing the LayoutUpdated event. This event fires each time layout occurs, which is typically as elements ae added to the visual tree. WHen this event fires inspect your TextBox.Text property to see if it is set.

This solved the problem for me :)

<TextBlock FontSize="16" FontWeight="Bold" Foreground="White" Margin="4,0,4,0" Text="{Binding CategoryName}" Loaded="TextBlock_Loaded" />

Loaded event in the inner Text block rather than the upper textblock because by the time this is loaded the upper text block's text is already bound so i can retrive the ID :)