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Passing Data from Main Window to a User Control's VewModel

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Stephen
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Stephen asked on 31 Jul 2014, 09:27 PM
I am coding in C#, using the MVVM pattern. I have a Main Window that uses several User Controls. I am trying to pass string data fro the Main Window to the View Model of the User Control. So far I have been able to pass the Main Window data to the User Control View and View code behind. However, I can't seem to expose that data to the User Control View Model. Here is what does work:

Main Window XAML,

UCV:SetupUC UC1="{Binding DataContext.ContainerData, ElementName=winCon, Mode=TwoWay}">
</UCV:SetupUC>

User Control XAML,

<TextBox x:Name="tbx1" HorizontalAlignment="Left" Height="23" Margin="159,22,0,0" TextWrapping="Wrap" Text="{Binding UC1, ElementName=root, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="120" RenderTransformOrigin="0.017,0.304"/>

User Control XAML code behind,

public partial class SetupUC : UserControl, INotifyPropertyChanged
    {

        public static readonly DependencyProperty UC1Property =
    DependencyProperty.Register(
      "UC1", typeof(string), typeof(SetupUC),
        new FrameworkPropertyMetadata()
        {
            PropertyChangedCallback = OnUC1Changed,
            BindsTwoWayByDefault = true
        });
        public string UC1
        {
            get { return (string)GetValue(UC1Property); }
            set
            {
                SetValue(UC1Property, value);
            }
        }
        private static void OnUC1Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (e.OldValue != e.NewValue)
            {
                // code to be executed on value update
            }
        }
        public SetupUC()
        {
            InitializeComponent();
            SetupViewModel svm = new SetupViewModel();
            this.DataContext = svm;
            Binding binding = new Binding("ViewModelStringProperty") { Source = svm, Mode = BindingMode.TwoWay };
            BindingOperations.SetBinding(this, SetupUC.UC1Property, binding);
        }

The last 2 lines above are an attempt to bind the DP to a property in the User Control View Model - which other posts have suggested as a possible solution. I have not been able to get the binding to work. Again, the TextBox x:Name="tbx1" is displaying the DP, UC1, just fine; it changes "realtime" when the bound data in the Main Window changes.

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Yana
Telerik team
answered on 01 Aug 2014, 09:49 AM
Hello Stephen,

This is quite a general question, not related to any of the controls from UI for WPF suite, that's why I would suggest that you also post it on MSDN forums or StackOverflow.

Regards,
Yana
Telerik
 
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Stephen
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answered on 01 Aug 2014, 03:05 PM
Thanks, I did try that...in fact there is quite a lengthy post in stackoverflow trying to figure it out...just thought this community might want a shot at it. For what it's worth, we are using Telerik controls and this situation is using Telerik controls, but, yes, it is not unique to Telerik controls.
:-)
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