c# - 通过 toolstripmenuitem 事件处理程序获取控件(treeView)

Question

类似这个问题: get contextmenustrip from toolstripmenuitem

除此之外，现在我需要找到在单击 ToolStripMenuItem 时打开其上下文菜单的对象。

SourceControl、Parent、Owner 和 GetParentControl() 均返回 null。

最初我有一个 TreeView，它的 ContextMenuStrip 属性已设置。

这是我的初步代码:

        ToolStripMenuItem tsmi = (ToolStripMenuItem)sender;
        ToolStripMenuItem tsmip = (ToolStripMenuItem)tsmi.OwnerItem;
        ContextMenuStrip cms = (ContextMenuStrip)tsmip.GetCurrentParent();
        TreeView tv = (TreeView)cms.SourceControl; 
        // returns null, but not in the cms_openHandler
        tv.Nodes.Add(new TreeNode("event fired."));

我是否错误地获取了 ContextMenuStrip？为什么 cms 的 SourceControl 属性在 OpenHandler 中起作用，但在 ToolStripMenuItem 事件处理程序中不起作用？

Form1.Designer.cs:

namespace TestWFA
{
partial class Form1
{
    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.components = new System.ComponentModel.Container();
        this.treeView1 = new System.Windows.Forms.TreeView();
        this.contextMenuStrip1 = new System.Windows.Forms.ContextMenuStrip(this.components);
        this.expandToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.childrenToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.allDescendantsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.collapseToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.childrenToolStripMenuItem1 = new System.Windows.Forms.ToolStripMenuItem();
        this.parentToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.childrenToolStripMenuItem2 = new System.Windows.Forms.ToolStripMenuItem();
        this.allDescendantsToolStripMenuItem1 = new System.Windows.Forms.ToolStripMenuItem();
        this.contextMenuStrip1.SuspendLayout();
        this.SuspendLayout();
        // 
        // treeView1
        // 
        this.treeView1.ContextMenuStrip = this.contextMenuStrip1;
        this.treeView1.Location = new System.Drawing.Point(64, 75);
        this.treeView1.Name = "treeView1";
        this.treeView1.Size = new System.Drawing.Size(262, 247);
        this.treeView1.TabIndex = 0;
        // 
        // contextMenuStrip1
        // 
        this.contextMenuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
        this.expandToolStripMenuItem,
        this.collapseToolStripMenuItem});
        this.contextMenuStrip1.Name = "contextMenuStrip1";
        this.contextMenuStrip1.Size = new System.Drawing.Size(153, 70);
        this.contextMenuStrip1.Opening += new System.ComponentModel.CancelEventHandler(this.contextMenuStrip1_Opening);
        // 
        // expandToolStripMenuItem
        // 
        this.expandToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
        this.childrenToolStripMenuItem,
        this.allDescendantsToolStripMenuItem});
        this.expandToolStripMenuItem.Name = "expandToolStripMenuItem";
        this.expandToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
        this.expandToolStripMenuItem.Text = "Expand";
        // 
        // childrenToolStripMenuItem
        // 
        this.childrenToolStripMenuItem.Name = "childrenToolStripMenuItem";
        this.childrenToolStripMenuItem.Size = new System.Drawing.Size(161, 22);
        this.childrenToolStripMenuItem.Text = "Children";
        this.childrenToolStripMenuItem.Click += new System.EventHandler(this.childrenToolStripMenuItem_Click);
        // 
        // allDescendantsToolStripMenuItem
        // 
        this.allDescendantsToolStripMenuItem.Name = "allDescendantsToolStripMenuItem";
        this.allDescendantsToolStripMenuItem.Size = new System.Drawing.Size(161, 22);
        this.allDescendantsToolStripMenuItem.Text = "All Descendants";
        this.allDescendantsToolStripMenuItem.Click += new System.EventHandler(this.allDescendantsToolStripMenuItem_Click);
        // 
        // collapseToolStripMenuItem
        // 
        this.collapseToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
        this.childrenToolStripMenuItem1,
        this.parentToolStripMenuItem,
        this.childrenToolStripMenuItem2,
        this.allDescendantsToolStripMenuItem1});
        this.collapseToolStripMenuItem.Name = "collapseToolStripMenuItem";
        this.collapseToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
        this.collapseToolStripMenuItem.Text = "Collapse";
        // 
        // childrenToolStripMenuItem1
        // 
        this.childrenToolStripMenuItem1.Name = "childrenToolStripMenuItem1";
        this.childrenToolStripMenuItem1.Size = new System.Drawing.Size(161, 22);
        this.childrenToolStripMenuItem1.Text = "All Ancestors";
        this.childrenToolStripMenuItem1.Click += new System.EventHandler(this.childrenToolStripMenuItem1_Click);
        // 
        // parentToolStripMenuItem
        // 
        this.parentToolStripMenuItem.Name = "parentToolStripMenuItem";
        this.parentToolStripMenuItem.Size = new System.Drawing.Size(161, 22);
        this.parentToolStripMenuItem.Text = "Parent";
        this.parentToolStripMenuItem.Click += new System.EventHandler(this.parentToolStripMenuItem_Click);
        // 
        // childrenToolStripMenuItem2
        // 
        this.childrenToolStripMenuItem2.Name = "childrenToolStripMenuItem2";
        this.childrenToolStripMenuItem2.Size = new System.Drawing.Size(161, 22);
        this.childrenToolStripMenuItem2.Text = "Children";
        this.childrenToolStripMenuItem2.Click += new System.EventHandler(this.childrenToolStripMenuItem2_Click);
        // 
        // allDescendantsToolStripMenuItem1
        // 
        this.allDescendantsToolStripMenuItem1.Name = "allDescendantsToolStripMenuItem1";
        this.allDescendantsToolStripMenuItem1.Size = new System.Drawing.Size(161, 22);
        this.allDescendantsToolStripMenuItem1.Text = "All Descendants";
        this.allDescendantsToolStripMenuItem1.Click += new System.EventHandler(this.allDescendantsToolStripMenuItem1_Click);
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(406, 365);
        this.Controls.Add(this.treeView1);
        this.Name = "Form1";
        this.Text = "Form1";
        this.contextMenuStrip1.ResumeLayout(false);
        this.ResumeLayout(false);

    }

    #endregion

    private System.Windows.Forms.TreeView treeView1;
    private System.Windows.Forms.ContextMenuStrip contextMenuStrip1;
    private System.Windows.Forms.ToolStripMenuItem expandToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem childrenToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem allDescendantsToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem collapseToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem childrenToolStripMenuItem1;
    private System.Windows.Forms.ToolStripMenuItem parentToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem childrenToolStripMenuItem2;
    private System.Windows.Forms.ToolStripMenuItem allDescendantsToolStripMenuItem1;
}
}

Form1.cs:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace TestWFA
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        treeView1.Nodes.Add(new TreeNode("root"));
    }

    private void childrenToolStripMenuItem1_Click(object sender, EventArgs e)
    {
        TreeView tv = GetSourceControl(sender) as TreeView;

        if (tv != null)
        {
            tv.Nodes.Add("Tree event catched!");
        }

        /*ToolStripMenuItem tsmi = (ToolStripMenuItem)sender;
        ToolStripMenuItem tsmip = (ToolStripMenuItem)tsmi.OwnerItem;


        ContextMenuStrip cms = (ContextMenuStrip)tsmip.GetCurrentParent();
        ToolStrip ts = tsmip.GetCurrentParent();

        IContainer c = cms.Container;
        TreeView tv = (TreeView)c;
        tv.Nodes.Add(new TreeNode("event fired."));*/
    }

    private object GetSourceControl(object Sender)
    {
        if (Sender as ContextMenuStrip != null)
        {
            return ContextMenuStrip.SourceControl;
        }

        var item = Sender as ToolStripItem;

        // move to root item
        while (item.OwnerItem != null)
        {
            item = item.OwnerItem;
        }

        // we have root item now, so lets take ContextMenuStrip object
        var menuObject = item.Owner as ContextMenuStrip;

        if (menuObject != null)
        {
            return menuObject.SourceControl;
        }

        return null;

    }

    private void parentToolStripMenuItem_Click(object sender, EventArgs e)
    {

    }

    private void childrenToolStripMenuItem2_Click(object sender, EventArgs e)
    {

    }

    private void allDescendantsToolStripMenuItem1_Click(object sender, EventArgs e)
    {

    }

    private void childrenToolStripMenuItem_Click(object sender, EventArgs e)
    {

    }

    private void allDescendantsToolStripMenuItem_Click(object sender, EventArgs e)
    {
    }

    private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
    {
        try
        {
            ContextMenuStrip cms = (ContextMenuStrip)sender;

        }
        catch
        {
        }
        try
        {
            TreeView tv = (TreeView)sender;
        }
        catch
        {
        }
    }

}
}

程序.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace TestWFA
{
static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}
}

不幸的是，我不知道有什么方法可以上传文件。我尝试将它们上传为 img，但没有用。

Answer 1

假设您将 ContextMenuStrip 设置为 TreeView。您可以轻松控制从 ContextMenuStrip 的 Opened 处理程序触发的菜单:

private void contextMenuStrip1_Opened(object sender, EventArgs e)
{
  TreeView tv = (sender as ContextMenuStrip).SourceControl as TreeView;
  tv.Nodes.Add("Tree event catched!");
}

如果将 ContextMenuStrip 设置为 treeView 的项目，此代码也可以工作。

PS:在实际应用中，您不应该使用像 (sender as ContextMenuStrip).SourceControl as TreeView; 这样的构造，因为可能存在空指针。您应该在每次转换后检查 null。

[编辑]
好的，现在我明白你的目的了。
当您处理菜单项时，sender 对象指向项目触发的事件。要找出弹出上下文菜单的控件，您应该做三件事:

1. 找到根项。很可能，被点击的项目是另一个项目或更深层次的子项目。
2. 您应该从根项目中找到 ContextMenuStrip 对象
3. 很容易从ContextMenuStrip的SourceControl属性中找出有趣的控件

我写了一个简单的方法来完成所有的工作:

/// <summary>
/// Gets controls for context menu
/// </summary>
/// <param name="Sender">Sender object from menu event handler</param>
/// <returns></returns>
private object GetSourceControl(Object Sender)
{
  // ContextMenuStrip sended?
  if (Sender as ContextMenuStrip != null)
  {
    ContextMenuStrip cms = Sender as ContextMenuStrip;
    return cms.SourceControl;
  }

  var item = Sender as ToolStripItem;

  // move to root item
  while (item.OwnerItem != null)
  {
    item = item.OwnerItem;
  }

  // we have root item now, so lets take ContextMenuStrip object
  var menuObject = item.Owner as ContextMenuStrip;

  if (menuObject != null)
  {
    return menuObject.SourceControl;
  }

  return null;
}

您可以简单地使用它。例如我们有菜单项点击事件处理程序:

private void toolStripMenuItem1_Click(object sender, EventArgs e)
{
  TreeView tv = GetSourceControl(sender) as TreeView;

  if (tv != null)
  {
    tv.Nodes.Add("Tree event catched!");
  }
}

[编辑2]
事实证明这个问题很早就被讨论过(SourceControl of ContextMenuStrip is Nothing in ToolStripMenuItem Click?)。单击根项时，SourceControl 属性不为空，但如果单击子项，则它等于空。所以解决方案是将 SourceControl 的值存储在某个地方以备后用。我建议在 Tag 属性中执行此操作。所以所有方法看起来像:

private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
{
  contextMenuStrip1.Tag = (sender as ContextMenuStrip).SourceControl;
}
....

private object GetSourceControl(object Sender)
{
  if (Sender as ContextMenuStrip != null)
  {
    return ContextMenuStrip.SourceControl;
  }

  var item = Sender as ToolStripItem;

  // move to root item
  while (item.OwnerItem != null)
  {
    item = item.OwnerItem;
  }

  // we have root item now, so lets take ContextMenuStrip object
  var menuObject = item.Owner as ContextMenuStrip;

  if (menuObject != null)
  {
    return menuObject.Tag;
  }

  return null;
}

在链接的问题中有私有(private)字段的解决方法，但 Tag 属性对我来说是习惯性的