[英]Can't bind to a command in my custom control
I created a control based of TextBox that looks like this: 我创建了一个基于TextBox的控件,如下所示:
public class DelayedTextBox : TextBox
{
public ICommand DelayedTextChangedCommand
{
get;
set;
}
}
I then create Foo.xaml with the following code: 然后,我使用以下代码创建Foo.xaml:
<h:DelayedTextBox DelayedTextChangedCommand="{Binding FooCommand}"/>
And I have FooViewModel (which is hooked up correctly in the XAML because other parts can bind to properties in FooViewModel) that has this: 我有FooViewModel(它在XAML中正确连接,因为其他部分可以绑定到FooViewModel中的属性)具有:
private ICommand _fooCommand;
public ICommand FooCommand
{
get
{
if (_fooCommand == null)
{
_fooCommand = new RelayCommand(CheckFoo, () => CanExecuteFooCheck());
}
return _fooCommand;
}
}
I am using RelayCommand from GalaSoft.MvvmLight, which works for other commands in my project 我正在使用GalaSoft.MvvmLight的RelayCommand,它适用于我项目中的其他命令
When I run my project, I get the following error when Foo.xaml gets loaded: 当我运行我的项目时,我在加载Foo.xaml时收到以下错误:
WinRT information: Failed to assign to property 'TestApp.Helpers.DelayedTextBox.DelayedTextChangedCommand'.
WinRT信息:无法分配给属性'TestApp.Helpers.DelayedTextBox.DelayedTextChangedCommand'。 [Line: 29 Position: 103] An exception of type 'Windows.UI.Xaml.Markup.XamlParseException' occurred in TestApp.exe but was not handled in user code WinRT information: Failed to assign to property 'TestApp.Helpers.DelayedTextBox.DelayedTextChangedCommand'.
[行:29位置:103] TestApp.exe中出现“Windows.UI.Xaml.Markup.XamlParseException”类型的异常,但未在用户代码WinRT信息中处理:无法分配给属性'TestApp.Helpers.DelayedTextBox。 DelayedTextChangedCommand”。 [Line: 29 Position: 103] The text associated with this error code could not be found.
[行:29位置:103]找不到与此错误代码关联的文本。
Failed to assign to property 'TestApp.Helpers.DelayedTextBox.DelayedTextChangedCommand'.
无法分配给属性'TestApp.Helpers.DelayedTextBox.DelayedTextChangedCommand'。 [Line: 29 Position: 103]
[线路:29位置:103]
I'm super confused as to why it can't bind properly, what am I doing wrong? 我非常困惑为什么它不能正确绑定,我做错了什么?
The issue was I didn't add a dependencyProperty as @Lynn Crumbling mentioned in the comments to my question. 问题是我没有在我的问题的评论中提到的@Lynn Crumbling中添加了dependencyProperty。
Adding the following to DelayedTextBox did the trick: 将以下内容添加到DelayedTextBox就可以了:
public static readonly DependencyProperty DelayedTextChangedCommandProperty =
DependencyProperty.Register(
"DelayedTextChangedCommand",
typeof(ICommand),
typeof(DelayedTextBox),
new PropertyMetadata(0));
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