在用户控件上设置绑定到主窗口的ViewModel

Question

I have following user control

<UserControl x:Class="Station.Controls.FilterTraceDataControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d">
            <TextBox x:Name="PartNumbTextBox" Width="120" VerticalAlignment="Bottom" HorizontalAlignment="Left" Margin="5,0,0,0" Height="25"/>
</UserControl>

I use it with my main window:

<Window
        xmlns:controls="clr-namespace:Station.Controls"
        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"


        mc:Ignorable="d" 
        x:Class="Station.MainWindow"
        Title="{Binding ApplicationTitle}" MinHeight="550" MinWidth="850" Height="650" Width="900"
        DataContext="{Binding Main, Source={StaticResource Locator}}">

        <controls:FilterTraceDataControl  Grid.Row="1" Visibility="{Binding FilterBarVisible ,Converter={StaticResource BooleanToVisibilityConverter}, Mode=TwoWay}"/>

</Window>

Window's Mainview has following property:

public string SelectedRefDesFilter
{
    get { return _selectedRefDesFilter; }
    set
    {
        _selectedRefDesFilter = value;
        RaisePropertyChanged("SelectedRefDesFilter");

    }
}

How I can databind "PartNumbTextBox" from UserControl to this Property.

Thanks.

Answer 1

On your UserControl's code-behind (FilterTraceDataControl.xaml.cs), add a DependencyProperty, like this:

public string Text
{
    get { return (string)this.GetValue(TextProperty); }
    set { this.SetValue(TextProperty, value); } 
}

public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
    "Text", typeof(string), typeof(FilterTraceDataControl),new PropertyMetadata(null));

Then bind your UserControl's TextBox to it by RelativeSource or ElementName:

<TextBox x:Name="PartNumbTextBox" Width="120" VerticalAlignment="Bottom" HorizontalAlignment="Left" Margin="5,0,0,0" Height="25"
         Text="{Binding Text, RelativeSource={RelativeSource AncestorType={x:Type controls:FilterTraceDataControl}}}" />

And in your view, just bind this new Text property to your existing SelectedRefDesFilter property.

<controls:FilterTraceDataControl Grid.Row="1" Visibility="{Binding FilterBarVisible ,Converter={StaticResource BooleanToVisibilityConverter}, Mode=TwoWay}"
                                 Text="{Binding SelectedRefDesFilter, Mode=TwoWay}" />

Answer 2

"{Binding DataContext.SelectedRefDesFilter, 
                            RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"

This should work, but i don't know the property in your UserControl which will be bounded to the one existing in the Window. The binding syntax should work.