Two way binding between textbox from parent silverlight's page to another local silverlight user control's textbox.

Question

I have used DependencyProperty to pass value from textbox at silverlight page to external silverlight user control located in same page and that works fine.

But the problem is I could not bind the Textbox in page in reverse way. i.e. when i need to have changes in parent page when its usercontrol's textbox text is changed.

The XAML:

<TextBox x:Name="TextDataCollectionAccounts" Width="200" Height="25" VerticalAlignment="Top"></TextBox>                    
<Local:CalControl   x:Name="RCal" DateRange="{Binding ElementName=TextDataCollectionAccounts, Path=Text, Mode=TwoWay}" Visibility="Collapsed"/>

How to bind "TextDataCollectionAccounts"(in silverlight page) with Textbox of "Local:CalControl"?

Answer 1

Basically never try to bind to the inner workings of a user control. Treat it like it was a third-party control and expose properties and events.

• Expose the Text property of the TextBox as a Text dependency property on your usercontrol.
• Catch the change event of the TextBox and raise a property change event for the new Text dependency property.
• Then you can simply bind to your new Text property on your user control.

If you need a specific example, just ask, but it sounds like you are almost there and know your DPs.

Answer 2

I did tried it following way but still not able to make it work:

page.xaml:

<StackPanel Orientation="Horizontal" VerticalAlignment="Top">
<TextBox x:Name="TextDataCollectionAccounts" Width="200" Height="25" VerticalAlignment="Top"></TextBox>
<ToggleButton x:Name="ButtonShowHideCalander" Content="Date" IsThreeState="False" Width="100" Click="ToggleButton_Click" Height="25" VerticalAlignment="Top"></ToggleButton>
<Local:MyUserControl x:Name="RCalanderData" DateRange="{Binding ElementName=TextDataCollectionAccounts, Path=Text, Mode=TwoWay}" Visibility="Collapsed"/>  

page.xaml.cs

private MyUserControl uc=new Rlight.Views.ExportImport.Controls.MyUserControl();
    public page()
    {
        InitializeComponent();            
        uc.OkButton.Click+=new RoutedEventHandler(Button_Click_control);
    }

    private void Button_Click_control(object sender, RoutedEventArgs e)
    {
        TextDataCollectionAccounts.Text = uc.DateDatas;
    }

MyUserControl.xaml

<TextBox x:Name="ResultSelectedDates" Grid.Row="1" Text="{Binding DateRange, Mode=TwoWay}" Width="100"/><Button x:Name="OkButton" Content="Ok" Height="40" Width="102"></Button>

MyUserControl.xaml.cs

public partial class MyUserControl : UserControl
{
    public static readonly DependencyProperty DateRangeProperty =
       DependencyProperty.Register("DateRange", typeof(String), typeof(MyUserControl), new PropertyMetadata(DataRangeChanged));

    public MyUserControl()
    {
        InitializeComponent();
        this.DataContext = new AccountingViewModel();
    }

    public string DateRange
    {
        get
        {
            return (string)GetValue(DateRangeProperty);
        }
        set
        {
            SetValue(DateRangeProperty, value);
        }
    }
    private static void DataRangeChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        MyUserControl item = (source as MyUserControl);
        if (item != null) item.ResultSelectedDates.Text = e.NewValue.ToString();
    }
}