通過綁定修改DataGrid的Column的Visibility



問題：因爲DataGridColumns不是可視樹的一部分，他們不能使用datagrid的datacontext。

解決方法1：代理類

    public class BindingProxy : Freezable
    {
        #region Overrides of Freezable
        protected override Freezable CreateInstanceCore()
        {
            return new BindingProxy();
        }
        #endregion

        public object Data
        {
            get { return (object)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }

        public static readonly DependencyProperty DataProperty =
            DependencyProperty.Register("Data", typeof(object),
                                         typeof(BindingProxy));
}

<DataGrid …>
        <DataGrid.Resources>
            <local:BindingProxy x:Key="proxy" Data="{Binding}"></local:BindingProxy>
        </DataGrid.Resources>
        <DataGrid.Columns>
        <DataGridTextColumn Header="Grade"
            Visibility="{Binding Data.MyColumnVisibility, Source={StaticResource proxy}}"
            Binding="{Binding Path=Grade}">
        </DataGridTextColumn>
    </DataGrid.Columns>
</DataGrid>

 解決方法2：代元素

1.在用戶控件的Resources里加一個代理FrameworkElement，並綁定控件的datacontex

2.把這個代理控件放在一個不可見的ContentControl裏

<FrameworkElement x:Name="dummyElement" Visibility="Collapsed" DataContext="{Binding}"/>

3.將DataGridColumn的Visibility綁定Datacontext中的屬性，比如IsEnable、或NoVisibility，Source採用x:Reference dummyElement。

4.如果綁定屬性是bool類型，還要使用Converter轉換一下

<DataGrid …>
    <DataGrid.Columns>
        <DataGridTextColumn Header="No." 
            Visibility="{Binding DataContext.IsEnable, Source={x:Reference dummyElement},Converter={StaticResource BooleanToVisibilityConverter}}"
            Binding="{Binding Path=No}">
        </DataGridTextColumn>
        <DataGridTextColumn Header="Name"
            Visibility="{Binding DataContext.NoVisibility, Source={x:Reference dummyElement}}"
            Binding="{Binding Path=Name}">
        </DataGridTextColumn>
    </DataGrid.Columns>
</DataGrid>

參考網址：http://stackoverflow.com/questions/22073740/binding-visibility-for-datagridcolumn-in-wpf?noredirect=1

代碼：http://download.csdn.net/download/xiudou_123/9836031