WPF：具有依赖项属性和子控件的UserControl [英] WPF: UserControl with Dependency Property and sub-controls
问题描述
我正在尝试在WPF中创建自己的非常简单的Usercontrol。它基本上只是一个组合框，其中包含一些其他逻辑。
我尝试使用此教程创建自己的Depdency-Property： http://www.codeproject.com/Articles/140620/WPF-Tutorial-Dependency-Property
I'm trying to create my own, very simple, Usercontrol in WPF. It's basically just a Combobox, with some additional Logic in it. I tried to create my own Depdency-Property using this Tutorial: http://www.codeproject.com/Articles/140620/WPF-Tutorial-Dependency-Property
到目前为止，这种方法还可以，但是如果属性更改，我也想在用户控件的组合框中反映出来。看来我无法将子控件直接绑定到新的Dependency-Project。
This is working fine so far, but if the property changes, I'd like to reflect this on the Combobox in the User-Control as well. It seems like I can't bind the subcontrol directly to my new Dependency-Project.
此刻我的代码如下：
public partial class ClassSelector : UserControl
{
public static readonly DependencyProperty CurrentValueProperty =
DependencyProperty.Register("CurrentValue", typeof(ClassType),
typeof(ClassSelector), new FrameworkPropertyMetadata());
public ClassType CurrentValue
{
get
{
return (ClassType)this.GetValue(CurrentValueProperty);
}
set
{
this.SetValue(CurrentValueProperty, value);
}
}
public ClassSelector()
{
this.DataContext = this;
InitializeComponent();
cmbClassType.ItemsSource = Enum.GetValues(typeof(ClassType));
}
}
设置依赖属性或组合框的值对我来说似乎很奇怪。
我试图通过以下方式将其直接绑定到xaml中：
Setting the value of the dependy-property or the Combobox seems weirds to me. I tried to bind it direclty in the xaml via:
<Grid>
<ComboBox x:Name="cmbClassType" SelectedItem="{Binding Path=CurrentValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectionChanged="cmbClassType_SelectionChanged" />
</Grid>
我尝试用组合框映射Dependicy-Project更改的事件，反之亦然，但这导致非常奇怪的代码，因为组合框的更改将不得不更改组合框的属性值和属性值。
I tried to map the Dependicy-Project changed Event with the combobox and visa versa, but this leads to very strange code, since the combobox change would have to change the property-value and the property-value the combobox.
我很确定一定有可能可以将DependencyProperty绑定到子控件，但是我找不到方法来完成这项工作。
I'm quite sure there has to be a possibility to bind a DependencyProperty to a subcontrol, but I can't find a way to make this work.
在此先感谢所有建议，并祝您周末愉快！
Thanks in advance for all advices guys and have a nice weekend
Matthias
Edith说：调用窗口需要将对象绑定到网格，而不是窗口。例如：
Edith says: The calling Window needs to bind the Object to the Grid, not to the Window, so for example:
grdMain.DataContext = new DeckSearch();
工作正常，同时
this.DataContext = new DeckSearch();
此行为仅在我的自定义控件上，所有其他控件与Window上的DataContext完美配合
This behavior is ONLY at my custom control, all other controls worked perfectly fine with the DataContext on the Window itself.
推荐答案
好的，在这里，我修复了您的代码，它在我的工作端正常工作
Okay so here I fixed your code and it is working at my end
UserControlCodeBehind
UserControlCodeBehind
public partial class ClassSelector : UserControl
{
public static readonly DependencyProperty CurrentValueProperty = DependencyProperty.Register("CurrentValue", typeof(ClassType),
typeof(ClassSelector), new FrameworkPropertyMetadata()
{
DefaultValue = ClassType.Type1,
BindsTwoWayByDefault = true,
PropertyChangedCallback = CurrentValueChanged,
DefaultUpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
});
private static void CurrentValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var obj = (ClassSelector)d;
obj.cmbClassType.SelectedValue = e.NewValue;
}
public ClassType CurrentValue
{
get
{
return (ClassType)this.GetValue(CurrentValueProperty);
}
set
{
this.SetValue(CurrentValueProperty, value);
}
}
public ClassSelector()
{
InitializeComponent();
cmbClassType.ItemsSource = Enum.GetValues(typeof(ClassType));
cmbClassType.SelectedValue = CurrentValue;
}
}
UserControl的Xaml部分
The Xaml part of the UserControl
<Grid>
<ComboBox x:Name="cmbClassType" SelectedValue="{Binding Path=CurrentValue}"/>
</Grid>
请检查它是否在您的终端工作。我没有添加任何额外的代码检查线程安全性和全部。
Please check if it is working at your end. I have not added any extra code checking for thread safety and all.
编辑
在我的解决方案中，当 CurrentValue Class Property 通知c $ c>更改。
In my solution I do get my Class Property notification when the CurrentValue changes.
下面是我的示例MainWindow代码。
Below is my sample MainWindow Code.
public partial class MainWindow : Window, INotifyPropertyChanged
{
public MainWindow()
{
InitializeComponent();
DataContext = this;
Task.Run(() =>
{
Thread.Sleep(1000);
Dispatcher.InvokeAsync(() =>
{
customCombobox.CurrentValue = ClassType.Type3;//Updating the UserControl DP
});
Thread.Sleep(2000);
this.CurrentValue = ClassType.Type2;//Updating my local Property
});
}
private ClassType _currentValue;
public ClassType CurrentValue
{
get { return _currentValue; }
set
{
_currentValue = value;
Debug.WriteLine("Value Changed to " + value.ToString());
RaisePropertyChanged("CurrentValue");
}
}
public event PropertyChangedEventHandler PropertyChanged;
void RaisePropertyChanged(string propName)
{
var pc = PropertyChanged;
if (pc != null)
pc(this, new PropertyChangedEventArgs(propName));
}
}
还有我的MainWindow.xaml
And my MainWindow.xaml
<Window x:Class="WpfApplication.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication"
Title="MainWindow" Height="250" Width="525">
<local:ClassSelector x:Name="customCombobox" Height="25" CurrentValue="{Binding CurrentValue}"/>
</Window>
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