使用 ValueConverter WPF 网格 IsEnabled
我有一个带有 Grid 和 TreeView 的 WPF 窗口。网格的数据上下文绑定到树视图上的选定项目。但是，由于并非所有 Treeviewitem 都适用，因此如果 treviewitem 不适用，我想禁用网格。因此，我创建了一个值转换器来执行空检查并返回布尔值。 （在这种情况下，适用的项目不会为空）
问题是从未使用值转换器。我设置了断点，但它们从未被击中。我正在使用其他值转换器，它们都工作得很好。
我有什么遗漏的吗？
<Grid Grid.Column="1" Grid.Row="0" DataContext="{Binding MyVal}" IsEnabled="{Binding MyVal, Converter={StaticResource NullCheckConverter}}" Margin="2,2,2,2">
这对于这个问题来说并不重要，但这里是 ValueConverter 代码：
internal class NullCheckValueConverter : IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return !(value == null);
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
}
I have a WPF window with a Grid and a TreeView. The datacontext for the Grid is bound to the selected item on the treeview. However, because not all treeviewitems are applicable, I want to disable the grid if the treviewitem isn't applicable. So, I created a value converter to do a null check and return a bool. (Applicable items would not be null in this case)
The problem is that the value converter is never used. I set break points and they are never hit. I have other value converters I'm using and they all work just fine.
Is there something I'm missing?
<Grid Grid.Column="1" Grid.Row="0" DataContext="{Binding MyVal}" IsEnabled="{Binding MyVal, Converter={StaticResource NullCheckConverter}}" Margin="2,2,2,2">
Not that it's important for this question but here is the ValueConverter code:
internal class NullCheckValueConverter : IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return !(value == null);
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
}
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这是因为您将 DataContext 绑定到与绑定
IsEnabled相同的值。因此，对于IsEnabled它实际上是在寻找 MyVal.MyVal。替换为：此外，如果您遇到绑定问题，请在调试模式输出窗口中检查绑定错误。
That's because you bind DataContext to the same value as you binding
IsEnabled. So forIsEnabledit actually looking for MyVal.MyVal. Replace to:Also further if you have issues with binding, check in debug mode output window for binding errors.