Question

I have a problem with Width property binding. One of the rows of grid must have a variable width. I decided to do this with binding width property, but this doesn’t work:

    private Int32 _avatarWidth;
    public Int32 AvatarWidth
    {
        get { return _avatarWidth; }
        set
        {
            _avatarWidth = value;
            RaisePropertyChanged(() => AvatarWidth);
        }
    }

XAML:

<ListBox Grid.Row="1" ItemsSource="{Binding CurrentDialog.Messages}" 
        HorizontalAlignment="Stretch" >
    <ListBox.ItemTemplate>
        <DataTemplate>
            ......
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="{ Binding AvatarWidth }" />
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>
            .......
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

But this doesn’t work. I have an exception in designer:

System.Reflection.TargetInvocationException
Exception has been thrown by the target of an invocation.
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Delegate.DynamicInvokeImpl(Object[] args)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)


System.InvalidOperationException
Layout measurement override of element 'Microsoft.Windows.Design.Platform.SilverlightViewProducer+SilverlightContentHost' should not return PositiveInfinity as its DesiredSize, even if Infinity is passed in as available size.
at System.Windows.UIElement.Measure(Size availableSize)
at MS.Internal.Designer.DeviceSkinViewPresenter.DeviceDesignerBackground.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.Decorator.MeasureOverride(Size constraint)
at Microsoft.Windows.Design.Interaction.DesignerView.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at MS.Internal.Designer.Viewport.MeasureOverride(Size availableSize)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
at System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged)
at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)
at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
at System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.Control.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Interop.HwndSource.SetLayoutSize()
at System.Windows.Interop.HwndSource.set_RootVisualInternal(Visual value)
at System.Windows.Interop.HwndSource.set_RootVisual(Visual value)
at MS.Internal.DeferredHwndSource.ProcessQueue(Object sender, EventArgs e)

Answer 1

First: Width of ColumnDefinition isn’t Int32 it is GridLength structure. Pay attention, “*” isn’t integer.

Second: Width isn’t dependency property (and doesn’t implement INotifyPropertyChanged) so you can’t bind to this property.

For you case I can suggest two solution. Try to use VisualStateManager or implement your logic in property change event handler of other property.

Edit: Or you can do as Rana suggested. Set Width of ColumnDefinition property to “Auto” and bind to Width property of child that is located in this cell. In this case _avatarWidth should be double