本文提供俩种不需要手动添加编辑控件方法。

方法一：创建新的右键菜单添加“执行选择”按钮，且抑制TreeList自带菜单
结果展示：

 代码： 

private void Form1_Load(object sender, EventArgs e)
{
  CreateBarButtonItem();
}

private void CreateBarButtonItem() {

  // 创建右键菜单
  ContextMenuStrip contextMenuStrip = new ContextMenuStrip();
  // 添加 "执行选择" 菜单项
  ToolStripMenuItem execSelectedItem = new ToolStripMenuItem("执行选择");
  execSelectedItem.Click += ExecSelectedItem_Click; ;
  contextMenuStrip.Items.Add(execSelectedItem);
  // 关联右键菜单与 TreeList 控件
  treeList1.PopupMenuShowing += TreeList1_PopupMenuShowing;
}

 private void TreeList1_PopupMenuShowing(object sender, PopupMenuShowingEventArgs e)
 {
     // 禁用自带的右键菜单
     e.Allow = false;
 }

private void ExecSelectedItem_Click(object sender, EventArgs e)
{
  //处理“执行选择”事件逻辑
} 

方法二：在TreeList自带菜单基础上添加“执行选择”按钮

结果展示： 

 右键空节点 

 右键节点，保留自带菜单功能  

 右键列标题，保留自带菜单功能‍  

代码： 

private void Form1_Load(object sender, EventArgs e)
{
  treeList1.PopupMenuShowing += TreeList1_PopupMenuShowing;//自定义右键展示菜单
}

private void TreeList1_PopupMenuShowing(object sender, PopupMenuShowingEventArgs e)
{
  // 获取右键菜单
  if (e.Menu is TreeListMenu menu)
  {
    // 添加自定义按钮
    DXMenuItem execSelectedItem = new DXMenuItem("执行选择");
    execSelectedItem.Click += ExecSelectedItem_Click;
    // 将自定义按钮插入到菜单的末尾
    menu.Items.Add(execSelectedItem);
  }
}

private void ExecSelectedItem_Click(object sender, EventArgs e)
{
  //处理“执行选择”事件逻辑
}