C# winform TreeView 的右键菜单的下级菜单的选项视情况禁用方法

在右键菜单的Opening事件内获取鼠标的坐标如果不能强转成node，则取消响应

private void flowRightMenu_Opening(object sender, CancelEventArgs e)
        {
    
    
            // Select this node.
            var node_here = tv_Flows.GetNodeAt(Cursor.Position.X, Cursor.Position.X);
            if (node_here == null) e.Cancel = true;
        }

TreeView按钮点击事件执行顺序

MouseDown->NodeClick->MenuOpening->MouseUp