上下文菜单绑定到父窗口的的DataContext [英] Context Menu Binding to Parent Window's Datacontext

问题描述

我有绑定到我的虚拟机集合的TreeListControl。我也想定义有其标题文字绑定到我的虚拟机另一个字符串的treelistcontrol内的上下文菜单。我怎么可以设置在这种情况下，数据上下文？我试图

 ＆LT; Window.DataContext＆GT;
    ＆LT;型号：视图模型＆GT;＆LT; /型号：视图模型＆GT;
＆LT; /Window.DataContext>
＆LT;网格和GT;
＆LT;按钮Grid.Row =1命令={结合CellCheckedCommand}＆GT;＆LT; /按钮＆GT;    ＆LT; TextBlock的文本={结合的HeaderText}Grid.Row =2＆GT;
        ＆LT; TextBlock.ContextMenu＆GT;
            ＆LT;＆文本菜单GT;
                ＆LT;菜单项的DataContext ={绑定的RelativeSource = {的RelativeSource AncestorType = {X：类型窗口}}，路径=的DataContext}标题={结合的HeaderText}＆GT;＆LT; /菜单项＆GT;
            ＆LT; /文本菜单＆GT;
        ＆LT; /TextBlock.ContextMenu>
    ＆LT; / TextBlock的＆GT;
＆LT; /网格和GT;
 

，但它不工作。

下面是视图模型

 公共DelegateCommand CellCheckedCommand {搞定;组; }私人字符串_HeaderText;公共字符串的HeaderText
{
    得到
    {
        返回_HeaderText;
    }
    组
    {
        _HeaderText =价值;
        NotifyPropertyChanged（的HeaderText）;
    }
}公共无效NotifyPropertyChanged（字符串名称）
{
    如果（的PropertyChanged！= NULL）
    {
        的PropertyChanged（这一点，新PropertyChangedEventArgs（名））;
    }
}私人无效CellCheckedMethod（）
{
    的HeaderText =更改;
}
 

解决方案

为你的窗口提供一个名称，并明确绑定到它，如

 ＆LT;窗​​口x：名称=ReportsPage/＆GT;... ＆LT;菜单项的DataContext ={绑定的ElementName = ReportsPage}/＆GT;
 

---

更新

由于上下文菜单实际上是在自己的窗口，绑定是有点棘手。因此，最好的办法是走了的RelativeSource 上下文的父，并从那里拉头文本：

 ＆LT; Window.DataContext＆GT;
        ＆lt;局部：MainVM的HeaderText =Jabberwocky/＆GT;
    ＆LT; /Window.DataContext>    ...＆LT; TextBlock的文本={结合的HeaderText}＆GT;
    ＆LT; TextBlock.ContextMenu＆GT;
        ＆LT;＆文本菜单GT;＆LT;菜单项标题={绑定路径= Parent.DataContext.HeaderText，
                    的RelativeSource = {自我的RelativeSource}}/＆GT;        ＆LT; /文本菜单＆GT;
    ＆LT; /TextBlock.ContextMenu>
 

这对于这样的背景下产生的这种

I have a TreeListControl that binds to a collection in my VM. I also want to define the context menu inside the treelistcontrol having its header text bind to another string in my VM. how can I set the data context in this case? I tried to

<Window.DataContext>
    <model:ViewModel></model:ViewModel>
</Window.DataContext>
<Grid>
<Button Grid.Row="1"  Command="{Binding CellCheckedCommand}"></Button>

    <TextBlock Text="{Binding HeaderText}" Grid.Row="2">
        <TextBlock.ContextMenu>
            <ContextMenu>
                <MenuItem DataContext="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}}, Path=DataContext}"  Header="{Binding HeaderText}"></MenuItem>
            </ContextMenu>
        </TextBlock.ContextMenu>
    </TextBlock>
</Grid>

but it doesn't work.

Here is the ViewModel

public DelegateCommand CellCheckedCommand { get; set; }

private String _HeaderText;

public String HeaderText 
{
    get
    {
        return _HeaderText;
    }
    set
    {
        _HeaderText = value;
        NotifyPropertyChanged("HeaderText");
    }
}

public void NotifyPropertyChanged(String name)
{ 
    if(PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(name));
    }
}

private void CellCheckedMethod()
{
    HeaderText = "Changed";
}

解决方案

Provide a name for your window and explicitly bind to it such as

<window  x:Name="ReportsPage"/>

...

 <MenuItem DataContext="{Binding ElementName=ReportsPage}"/>

---

UPDATE

Since the context menu is actually in its own window, binding is a bit trickier. Hence the best bet is to walk up the RelativeSource to the context's parent and pull the header text from there:

    <Window.DataContext>
        <local:MainVM HeaderText="Jabberwocky" />
    </Window.DataContext>

    ...

<TextBlock Text="{Binding HeaderText}">
    <TextBlock.ContextMenu>
        <ContextMenu>

<MenuItem Header="{Binding Path=Parent.DataContext.HeaderText, 
                    RelativeSource={RelativeSource Self}}" />

        </ContextMenu>
    </TextBlock.ContextMenu>

Which for this context produces this

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