Question

似乎无法在Silverlight 4中绑定DataGridTemplateColumn的visibility属性。我做了一些谷歌搜索，似乎有一些帖子暗示要做with the fact that it was not a DependencyObject以及如何this would change in SL4，但似乎并非如此。

要解决它，我在datagrid加载事件的代码中执行此操作，但我很好奇为什么会出现这种情况？

以下是我收到的错误消息（使用返回Visibility值的转换器）：

{System.ArgumentException: Object of type 'System.Windows.Data.Binding' cannot be converted to type 'System.Windows.Visibility'.
   at System.RuntimeType.TryChangeType(Object value, Binder binder, CultureInfo culture, Boolean needsSpecialCast)
   at System.RuntimeType.CheckValue(Object value, Binder binder, CultureInfo culture, BindingFlags invokeAttr)
   at System.Reflection.MethodBase.CheckArguments(Object[] parameters, Binder binder, BindingFlags invokeAttr, CultureInfo culture, Signature sig)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimePropertyInfo.SetValue(Object obj, Object value, BindingFlags invokeAttr, Binder binder, Object[] index, CultureInfo culture)
   at System.Reflection.RuntimePropertyInfo.SetValue(Object obj, Object value, Object[] index)
   at MS.Internal.XamlMemberInfo.SetValue(Object target, Object value)
   at MS.Internal.XamlManagedRuntimeRPInvokes.SetValue(XamlTypeToken inType, XamlQualifiedObject& inObj, XamlPropertyToken inProperty, XamlQualifiedObject& inValue)}

Answer 1

虽然DataGridTemplateColumn确实来自DependencyObject，但它没有为其Visibility属性定义DependencyProperty。实际上它没有定义任何依赖属性，因此你仍然无法获得任何绑定它。

Answer 2

在数据网格模板列上将此选项用于要绑定的任何属性：

public class CustomDataGridTemplateColumn : DataGridTemplateColumn
{
    public static readonly DependencyProperty VisibilityBindingProperty = DependencyProperty.Register(
      "VisibilityBinding", typeof(Visibility), typeof(CustomDataGridTemplateColumn), new PropertyMetadata(Visibility.Collapsed, new PropertyChangedCallback(OnVisibilityChanged)));

    public Visibility VisibilityBinding
    {
        get { return (Visibility)this.GetValue(VisibilityBindingProperty); }
        set { this.SetValue(VisibilityBindingProperty, value); }
    }

    private static void OnVisibilityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        ((CustomDataGridTemplateColumn)d).Visibility = (Visibility)e.NewValue;
    }
}

为什么我不能在Silverlight 4中绑定DataGridTemplateColumn的可见性？

2 个答案: