禁用某些 DatGrid 单元格 WPF 上的上下文菜单

Question

我定义了一个像这样的数据网格 ::

 <cc:PEDataGrid AutoGenerateColumns="False"
               ItemsSource="{Binding Rows}"
               Width="Auto"                
               PreviewMouseRightButtonDown="PEGrid_PreviewMouseRightButtonDown"
               Loaded="CommonPEGrid_Loaded">             
      <wpfkit:DataGrid.ContextMenu>
        <ContextMenu>
            <MenuItem Header="Cut" />
            <MenuItem Header="Copy"/>
            <MenuItem Header="Paste"/>              
        </ContextMenu>
    </wpfkit:DataGrid.ContextMenu>
</cc:PEDataGrid>

当右键单击完成时，它会在每个单元格上显示 contextMenu。
我想禁用除标题之外的所有单元格的上下文菜单，以及某些条件下的标题。 （我不想使用 DataGridHeaderStyle，因为我不想在这里解释一些其他问题。）

我已经在数据网格上和我的处理程序中为 PreviewMouseRightButtonDown 定义了一个处理程序尝试做这样的事情：：

    private void PEGrid_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
    {
        DependencyObject depObj = (DependencyObject)e.OriginalSource;

        while ((depObj != null) && !(depObj is DataGridColumnHeader))
        {
            depObj = VisualTreeHelper.GetParent(depObj);
        }

        if (depObj == null)
        {
            return;
        }

        if (depObj is DataGridColumnHeader)
        {
            //some condition here which says whether contextmenu is required on this header

            (depObj as DataGridColumnHeader).ContextMenu = null;
            //the above line is not working!!!!
        }
        else
        {
             (depObj as DataGridCell).ContextMenu = null;
              //the above line not working!!!!
         }
    }

我想知道我哪里出错了！！请帮助我解决这个问题。如果我以错误的方式实现了我的要求，也指导我以更好的方式去做:)

Answer 1

嘿我解决了::我修改后的代码如下:::

private void PEGrid_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
    DependencyObject depObj = (DependencyObject)e.OriginalSource;

    while ((depObj != null) && !(depObj is DataGridColumnHeader))
    {
        depObj = VisualTreeHelper.GetParent(depObj);
    }

    if (depObj == null)
    {
        return;
    }

    if (depObj is DataGridColumnHeader)
    {
          dg.ContextMenu.Visibility = Visibility.Visible;  //works
    }
    else
    {
          dg.ContextMenu.Visibility = Visibility.Collapsed; //works
     }
}

Answer 2

我认为这个版本更快，而且您不必设置上下文菜单的可见性。如果单击的是列标题，只需取消单击事件即可。

private void PEGrid_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
    var depObj = (DependencyObject)e.OriginalSource;
    while ((depObj != null) && !(depObj is DataGridColumnHeader))
    {
        depObj = VisualTreeHelper.GetParent(depObj);
    }
    if (depObj is DataGridColumnHeader)
    {
        e.Handled = true;
    }
}

Answer 3

我在 DataGridCell 中有 RichTextBox，它不是 VisualTree 元素。我的代码：

private void dgLog_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
    {
        FrameworkContentElement fce = e.OriginalSource as FrameworkContentElement;
        DependencyObject depObj = e.OriginalSource as DependencyObject;
        DataGridCell dgc = null;
        DataGridRow dgr = null;
        try
        {
            while (fce != null && !(fce is DataGridCell))
            {
                depObj = fce.Parent;
                fce = depObj as FrameworkContentElement;
            }
            while (depObj != null && !(depObj is DataGridRow))
            {
                if (depObj is DataGridCell)
                    dgc = depObj as DataGridCell;
                depObj = VisualTreeHelper.GetParent(depObj);
            }
            if (depObj == null)
                return;
            dgr = depObj as DataGridRow;
            if (((LogRecord)dgr.Item).SourceType == "FileMessage" && dgc.Column.DisplayIndex == 1)
                dgLog.ContextMenu = cm_dgLog;
            else
                dgLog.ContextMenu = null;
        }
        catch (Exception ex)
        {
            MessageBox.Show(...);
            TraceHelper.TraceError(ex, GetType());
        }
    }//private void dgLog_PreviewMouseRightButtonDown

LogRecord 是 DataGridColumn.Item 的类型

Answer 4

    private void dgLog_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
    {
        FrameworkContentElement fce = e.OriginalSource as FrameworkContentElement;
        DependencyObject depObj = e.OriginalSource as DependencyObject;
        DataGridCell dgc = null;
        DataGridRow dgr = null;
        try
        {
            while (fce != null && !(fce is DataGridCell))
            {
                depObj = fce.Parent;
                fce = depObj as FrameworkContentElement;
            }
            while (depObj != null && !(depObj is DataGridRow))
            {
                if (depObj is DataGridCell)
                    dgc = depObj as DataGridCell;
                depObj = VisualTreeHelper.GetParent(depObj);
            }
            if (depObj == null)
                return;
            dgr = depObj as DataGridRow;
            if (((LogRecord)dgr.Item).SourceType == "FileMessage" && dgc.Column.DisplayIndex == 1)
                dgLog.ContextMenu = cm_dgLog;
            else
                dgLog.ContextMenu = null;
        }
        catch (Exception ex)
        {
            MessageBox.Show(...);
            TraceHelper.TraceError(ex, GetType());
        }
    }//private void dgLog_PreviewMouseRightButtonDown

对不起。第一次尝试不太好。