How to bind DataGridColumn.Visibility?

Question

I have an issue similar to the following post:

Silverlight DataGridTextColumn Binding Visibility

I need to have a Column within a Silverlight DataGrid be vis

Answer 1

Here's the solution I've come up with using a little hack.

First, you need to inherit from DataGrid.

public class DataGridEx : DataGrid
{
    public IEnumerable HiddenColumns
    {
        get { return (IEnumerable)GetValue(HiddenColumnsProperty); }
        set { SetValue(HiddenColumnsProperty, value); }
    }

    public static readonly DependencyProperty HiddenColumnsProperty =
        DependencyProperty.Register ("HiddenColumns", 
                                     typeof (IEnumerable), 
                                     typeof (DataGridEx),
                                     new PropertyMetadata (HiddenColumnsChanged));

    private static void HiddenColumnsChanged(object sender,
                                             DependencyPropertyChangedEventArgs args)
    {
        var dg = sender as DataGrid;
        if (dg==null || args.NewValue == args.OldValue)
            return;

        var hiddenColumns = (IEnumerable)args.NewValue;
        foreach (var column in dg.Columns)
        {
            if (hiddenColumns.Contains ((string)column.GetValue (NameProperty)))
                column.Visibility = Visibility.Collapsed;
            else
                column.Visibility = Visibility.Visible;
        }
    }
}

The DataGridEx class adds a new DP for hiding columns based on the x:Name of a DataGridColumn and its descendants.

To use in your XAML:

    
                            Header="Count"
                            Binding={Binding CountOfItems}"
    

You need to add these to your ViewModel or whatever data context you use.

private IEnumerable _hiddenColumns;
public IEnumerable HiddenColumns
{
    get { return _hiddenColumns; }
    private set
    {
        if (value == _hiddenColumns)
            return;

        _hiddenColumns = value;
        PropertyChanged (this, new PropertyChangedEventArgs("HiddenColumns"));
    }
}

public void SomeWhereInYourCode ()
{
    HiddenColumns = new List {"uiDataCountOfItems"};
}

To unhide, you only need to remove the corresponding name from the list or recreate it without the unhidden name.