不同的行爲命令

Question

我有RibbonApplicationMenu在我的應用程序類似於此示例：

<RibbonApplicationMenu> 
    <RibbonApplicationMenuItem Header="Open Project..." Command="{Binding OpenProjectCommand}" /> 
    <RibbonApplicationMenuItem Header="Save Project..." Command="{Binding SaveProjectCommand}" /> 
    <RibbonApplicationMenuItem Header="Exit" Command="{Binding CloseWindowCommand}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type RibbonWindow}}}" /> 
    <RibbonApplicationMenu.FooterPaneContent> 
     <RibbonButton Label="Exit" Command="{Binding CloseWindowCommand}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type RibbonWindow}}}" /> 
    </RibbonApplicationMenu.FooterPaneContent> 
</RibbonApplicationMenu> 

private void CloseWindow (Object parameter) 
{ 
    ((Window) parameter).Close(); 
} 

在該例子中存在具有通過相同的參數綁定到相同的命令和RibbonApplicationMenuItem項RibbonButton和。該命令執行CloseWindow（）函數。我感到好奇的是，當單擊RibbonApplicationMenuItem時，該函數的參數是指向RibbonWindow的指針。但是，單擊RibbonButton時，該函數的參數爲​​空。

爲什麼行爲會有所不同？

Answer 1

將FooterPaneContent設置爲另一個控件（RibbonButton）混淆邏輯樹，這就是爲什麼RelativeAncestor不起作用。

在換句話說，即使你綁定到按鈕本身，與LogicalTreeHelper遍歷是不行的（VisualTreeHelper不會工作，要麼因爲面板是一個PopUp，住在一個單獨的視覺樹）：

<r:RibbonApplicationMenu.FooterPaneContent> 
    <r:RibbonButton Label="Exit" Command="{Binding CloseWindowCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Self}}" /> 
</r:RibbonApplicationMenu.FooterPaneContent> 

private void CloseWindow(object parameter) 
{ 
    RibbonButton _button = (RibbonButton)parameter; 

    // _appMenu will be null 
    DependencyObject _appMenu = LogicalTreeHelper.GetParent(_button); 
} 

所以，你的選擇是：

1. 綁定到自我和使用_button.Ribbon屬性來獲取Ribbon並遍歷邏輯樹以獲得RibbonWindow。

2. 設置ContentTemplate而不是Content。但要小心傳播DataContext。

<r:RibbonApplicationMenu.FooterPaneContentTemplate> 
    <DataTemplate> 
     <r:RibbonButton Label="Exit" DataContext="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type r:RibbonApplicationMenu}}, Path=DataContext}" Command="{Binding Path=CloseWindowCommand}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type r:RibbonWindow}}}" /> 
    </DataTemplate> 
</r:RibbonApplicationMenu.FooterPaneContentTemplate> 

private void CloseWindow(object parameter) 
    { 
     ((Window)parameter).Close(); 
    }