绑定到UserControl中的FrameworkElement

Question

我得到了一个自定义UserControl (MyControl)与几个属性(这工作得很好)。我想要一个新的属性，让页面使用UserControl"粘贴"一些内容直接显示在UserControl -例如路径。我试过了;ContentPresenter, ContentControl, StackPanel, with no luck…

MyControl.xaml

<ContentControl Grid.Column="0" Content="{Binding MyContent, ElementName=root}"></ContentControl>

MyControl.xaml.cs

public object MyContent
{
  get { return (object)GetValue(MyContentProperty); }
  set { SetValue(MyContentProperty, value); }
}
public static readonly DependencyProperty MyContentProperty =
  DependencyProperty.Register("MyContent", typeof(object), typeof(MyControl), new PropertyMetadata(null));

SomePage.xml

<mycontrols:MyControl x:Name="FavoritesButton">
  <mycontrols:MyControl.MyContent>
    <Path Data="M1540.22,2082.07L1546.95,2102.78 1568.73,2102.78 1551.11,2115.58 1557.84,2136.29 1540.22,2123.49 1522.6,2136.29 1529.33,2115.58 1511.71,2102.78 1533.49,2102.78 1540.22,2082.07z" Stretch="Uniform" Fill="#FFFFFFFF" Width="50" Height="50" Margin="30"></Path>
  </mycontrols:MyControl.MyContent>
</mycontrols:MyControl>

Answer 1

我有以下工作真的很好。(虽然这有点违背MVVM的原则……我仍然喜欢在主窗口的单个框架区域动态地处理我的用户控件)

我MainWindow.xaml

:

<!-- Main Frame -->
<Grid Grid.Column="1" Margin="10" Name="MainWindowFrameContent">
   <ItemsControl ItemsSource="{Binding Path=MainWindowFrameContent}" >
      <!-- This controls the height automatically of the user control -->
      <ItemsControl.ItemsPanel>
         <ItemsPanelTemplate>
            <UniformGrid Columns="1" IsItemsHost="True"/>
         </ItemsPanelTemplate>
      </ItemsControl.ItemsPanel>
   </ItemsControl>
</Grid>

我MainViewModel.cs

:

using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Input;
using myProject.View;
using myProject.Models;
namespace myProject.ViewModel
{
    public class MainViewModel : ObservableObject
    {
        public MainViewModel() { }
        // This handles adding framework (UI) elements to the main window frame
        ObservableCollection<FrameworkElement> _MainWindowFrameContent = new ObservableCollection<FrameworkElement>();
        public ObservableCollection<FrameworkElement> MainWindowFrameContent
        {
            get { return _MainWindowFrameContent; }
            set { _MainWindowFrameContent = value; RaisePropertyChangedEvent("MainWindowFrameContent"); }
        }
    }
}

MainViewModel.cs是一个"公共类MainViewModel: ObservableObject"。这允许我实现"RaisePropertyChangedEvent"，这样当我改变"MainWindowFrameContent"的值时，绑定将成功更新。

我ObservableObject.cs

:

using System.ComponentModel;
namespace myProject.ViewModel
{
    public class ObservableObject : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected void RaisePropertyChangedEvent(string propertyName)
        {
            var handler = PropertyChanged;
            if (handler != null)
                handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

然后，当我想添加一个项目到MainWindowFrameContent，我只需在我的MainViewModel.cs中执行以下操作:

void _AddNewUserControl()
{
    myUserControl hControl = new myUserControl();
    MainWindowFrameContent.Clear(); // Clear the frame before displaying new content
    MainWindowFrameContent.Add(hControl);
}

然后您可以创建任意多的用户控件。您想要显示的每个命令都可以在VM中拥有自己的void _AddNewUserControl类型方法，并且它将显示到主窗口。同样，它与MVVM框架有点相反，但它从代码库中保持了相当干净。

Answer 2

我让它工作…解决方案如下:

MyControl.xaml

<ContentControl Content="{Binding Shape, ElementName=root}" />

MyControl.xaml.cs

public Shape Shape
{
    get { return (Shape)GetValue(ShapeProperty); }
    set { SetValue(ShapeProperty, value); }
}
public static readonly DependencyProperty ShapeProperty =
        DependencyProperty.Register("Shape", typeof(Shape), typeof(MyControl), new PropertyMetadata(null));

SomePage.xml

<mycontrols:MyControl>
    <mycontrols:MyControl.Shape>
        <Path Data="M1540.22,2082.07L1546.95,2102.78 1568.73,2102.78 1551.11,2115.58 1557.84,2136.29 1540.22,2123.49 1522.6,2136.29 1529.33,2115.58 1511.71,2102.78 1533.49,2102.78 1540.22,2082.07z" Style="{StaticResource PathStyle}" />
    </mycontrols:MyControl.Shape>
</mycontrols:MyControl>