使用BooleanToVisibility转换器隐藏WPF中布局元素的网格中的列

Question

I am trying to bind the visibility property of a GRID column using a Boolean to Visibility Converter. The Grid is always visible even though the bool value is false. Please help me fix this issue. The code works perfectly fine for a datagrid but not for a Grid .Here is the code.

 <Window x:Class="MyApp.FirstWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:viewmodel="clr-namespace:MyApp.ViewModel" 
    xmlns:i="clr-namespace:System.Windows.Interactivity;  assembly=System.Windows.Interactivity"
    xmlns:y="clr-namespace:MyApp.Framework.Converter"
    xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF4" 
    DataContext="{Binding MyAppViewModel, Source={StaticResource Locator}}"
    MinHeight="530" MinWidth="275" Height="530" Width="275" Title="{Binding Title}"  >

 <Window.Resources>     
    <y:BoolToVisibilityConverter x:Key="boolToVisibilityConverter" />
</Window.Resources>
  <Grid Margin="5">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>     
    <Grid Grid.Row="1" Grid.Column="1" Name="gridTest"
       DataContext="{Binding GridDataContext, Mode=TwoWay}"   
       Visibility="{Binding GridVisibility, Mode= TwoWay, Converter=   {StaticResource boolToVisibilityConverter}}" >
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>

        <Label >Date</Label>
        <Label Grid.Column="1" Content="{Binding Date}" />

        <Label Grid.Row="1">Time</Label>
        <Label Grid.Row="1" Grid.Column="1" Content="{Binding Time}"/>
        </Grid>
</Grid>

BoolToVisibilityconverter.cs

  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Windows;
  using System.Windows.Data;
  using System.Globalization;

  namespace MyApp.Framework.Converter
  {
   public sealed class BoolToVisibilityConverter : IValueConverter
    {

    public object Convert(object value, Type targetType, object     parameter,         System.Globalization.CultureInfo culture)
    {
        if (parameter == null)
        {
            return ((bool)value == true) ? Visibility.Visible : Visibility.Hidden;
        }
        else if (parameter.ToString() == "Inverse")
        {
            return ((bool)value == true) ? Visibility.Collapsed : Visibility.Visible;
        }
        return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

MyAppViewModel.cs

public class MyAppViewModel : ViewModelBase, INotifyPropertyChanged
{

     private bool _isGridVisible = false;

     private bool _isLabelVisible = false;
     private MyItem _gridDataContext;
     public MyItem GridDataContext
    {
        get { return _gridDataContext; }
        set
        {
            _gridDataContext = value;
            OnPropertyChanged("GridDataContext");
        }
    }

     public bool IsLabelVisible
    {
        get
        {
            return _isLabelVisible;
        }

        set
        {
            if (_isLabelVisible == value)
            {
                return;
            }

            _isLabelVisible = value;
            OnPropertyChanged("IsLabelVisible");
        }
    }
    public bool GridVisibility
    {
        get
        {
            return _isGridVisible;
        }

        set
        {
            if (_isGridVisible == value)
            {
                return;
            }

            _isGridVisible = value;
            OnPropertyChanged("GridVisibility");
        }
    }


    /// <summary>-
    /// Initializes a new instance of the AppViewModel class.
    /// </summary>      
    public AppViewModel()
    {
        _gridDataContext = new MyItem();
        //other code.
    }
  private void UpdateMyItem()
    {
        try
        {
            bool wasSet = false;

            if (test== null)
            {
                SetVisible(false, "No feature selected.");
            }
            else
            {
                SetVisible(false, String.Format("No test         
                information  selected for my item {0}.",    
                 test.name.ToString().PadLeft(5, '0')));
            }
         }
   private void SetVisible(bool wasSet, string msg)
    {

        //under construction
        if (wasSet )
        {
            Dispatcher.CurrentDispatcher.DynamicInvoke(delegate()
            {
                GridVisibility = true;
                IsLabelVisible = false;

            });
        }
        else if (!wasSet )            
        {
            Dispatcher.CurrentDispatcher.DynamicInvoke(delegate()
            {
                GridVisibility = false;
                IsLabelVisible = true;
                LabelContent = msg;

            });
        }
    }

}

}

I haven't found any answers appropriate for what I am doing. The blogs have answers to hiding/showing Datagrid columns and not Grid layout element. Is this possible? Is my XAML for the Visibility property of the Grid OK? Thanks for your help.

Solution: MyAppViewModel.cs

      private void SetVisible(bool wasSet, string msg)
      {  
         if (wasSet)
         {
             Dispatcher.CurrentDispatcher.DynamicInvoke(delegate()
             {
                 GridDataContext.GridVisibility = true;
                IsLabelVisible = false;                   
             });
         }
         else if (!wasSet)            
        {
             Dispatcher.CurrentDispatcher.DynamicInvoke(delegate()
             {
                 GridDataContext.GridVisibility = false;           

                 IsLabelVisible = true;
                 LabelContent = msg;                   
             });
         }
     }

Answer 1

As stated by @ Ayyappan Subramanian it's due to different DataContexts.

Window's context is the MyAppViewModel which has GridVisibility property implemented but Grid's context is value of GridDataContext property within MyAppViewModel (typeof MyItem ).

So you need to point to the right DataContext when binding Visibility

<Grid Grid.Row="1" 
      Grid.Column="1"
      Name="gridTest"
      DataContext="{Binding GridDataContext}"
      Visibility="{Binding DataContext.GridVisibility, 
                   Mode=TwoWay, 
                   RelativeSource={RelativeSource FindAncestor, AncestorType=Window},
                   Converter={StaticResource BoolToVisibilityConverter}}">

Or if this is not an option, change the implementation of MyItem to include given property.

public class MyItem : ViewModelBase
{
    // Current implementation goes here...

    // GridVisibility implementation
    private bool _isGridVisible = false;
    public bool GridVisibility
    {
        get { return _isGridVisible; }
        set
        {
            _isGridVisible = value;
            RaisePropertyChanged();
        }
    }
}