WPF toolkit data column visibility binding

Question

I want to bind datagrid view column visibility with a property of class. I am passing a collection as ItemSource to grid.

I am not able to do this. Any idea why?

Answer 1

This one is a bit tricky. The problem comes from the fact that DataGrid.Columns is just a property and not part of the visual tree. This means that normal binding tools like ElementName or RelativeSource will not work. If, however, you override the Metadata for the DataGrid.DataContext property, you can get it to work properly. Example code below:

<Window x:Class="DataGridColumnVisibilitySample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:tk="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
    xmlns:l="clr-namespace:DataGridColumnVisibilitySample"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <l:VisibilityConverter x:Key="VisibilityC" />
    </Window.Resources>
    <DockPanel LastChildFill="True">
        <CheckBox DockPanel.Dock="Top" Margin="8" Content="Show Column B" IsChecked="{Binding ShowColumnB}" />
        <tk:DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="False" CanUserAddRows="False">
            <tk:DataGrid.Columns>
                <tk:DataGridTextColumn Header="Column A" Binding="{Binding ColumnA}" />
                <tk:DataGridTextColumn Header="Column B" Binding="{Binding ColumnB}"
                                       Visibility="{Binding (FrameworkElement.DataContext).ShowColumnB,
                                                            RelativeSource={x:Static RelativeSource.Self},
                                                            Converter={StaticResource VisibilityC}}" />
                <tk:DataGridTextColumn Header="Column C" Binding="{Binding ColumnC}" />
            </tk:DataGrid.Columns>
        </tk:DataGrid>
    </DockPanel>
</Window>

---

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using System.Windows;
using System.Windows.Data;
using Microsoft.Windows.Controls;

namespace DataGridColumnVisibilitySample
{
    public partial class Window1 : INotifyPropertyChanged
    {
        public Window1()
        {
            InitializeComponent();
            new DataGridContextHelper();  // Initialize Helper
            Items = Enumerable.Range(1, 3).Select(i => new MyItem {ColumnA = "A" + i, ColumnB = "B" + i, ColumnC = "C" + i}).ToList();
            DataContext = this;
        }

        public List<MyItem> Items { get; private set; }

        private bool mShowColumnB;
        public bool ShowColumnB
        {
            get { return mShowColumnB; }
            set
            {
                if (mShowColumnB == value) return;
                mShowColumnB = value;
                if (PropertyChanged != null)
                    PropertyChanged(this, new PropertyChangedEventArgs("ShowColumnB"));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }

    public class DataGridContextHelper
    {
        static DataGridContextHelper()
        {
            FrameworkElement.DataContextProperty.OverrideMetadata(typeof(DataGrid),
                new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.Inherits, OnDataContextChanged));
        }

        public static void OnDataContextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var grid = d as DataGrid;
            if (grid == null) return;
            foreach (var col in grid.Columns)
                col.SetValue(FrameworkElement.DataContextProperty, e.NewValue);
        }
    }

    [ValueConversion(typeof(bool), typeof(Visibility))]
    public class VisibilityConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is bool && (bool)value)
                return Visibility.Visible;
            return Visibility.Collapsed;
        }

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

    public class MyItem
    {
        public string ColumnA { get; set; }
        public string ColumnB { get; set; }
        public string ColumnC { get; set; }
    }
}

I sourced this post by Jaime Rodriguez in creating my solution.

Answer 2

Can I bind the data in the header of the DataGridColumn in a simular way?

Answer 3

That works as long your datagrid is in a window, control, etc, if it's in a controltemplate this still won't work