C#-----Winform界面实现右键菜单功能

1.新建Form窗体，向其中添加ContextMenuStrip控件

2.点击ContextMenuStrip控件属性Items，添加MenuItem或Separator组件

3.点击一级菜单，添加MenuItem或Separator组件，形成二级菜单

4.Demo代码

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

namespace Contextmenu
{
    public partial class frmContextmenu : Form
    {
        public frmContextmenu()
        {
            InitializeComponent();
        }

        private void tSMICenter_Click(object sender, EventArgs e)
        {
            int height =SystemInformation.WorkingArea.Height;
            int width = SystemInformation.WorkingArea.Width;
            int formheight = this.Size.Height;
            int formwidth = this.Size.Width;
            int newformx = width / 2 - formwidth / 2;
            int newformy = height / 2 - formheight / 2;
            this.SetDesktopLocation(newformx, newformy);
        }

        private void tSMILargen_Click(object sender, EventArgs e)
        {
            this.Width =this.Width+100;
            this.Height = this.Height + 100;
        }

        private void tSMISmaller_Click(object sender, EventArgs e)
        {
            this.Width = this.Width - 100;
            this.Height = this.Height- 100;
        }

        private void frmContextmenu_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Button==MouseButtons.Right)
            {
                contextMenuStrip.Show(MousePosition.X,MousePosition.Y);
            }
        }
    }
}

namespace Contextmenu
{
    partial class frmContextmenu
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要修改
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.labelX1 = new DevComponents.DotNetBar.LabelX();
            this.contextMenuStrip = new System.Windows.Forms.ContextMenuStrip(this.components);
            this.toolStripMenuItem1 = new System.Windows.Forms.ToolStripMenuItem();
            this.tSMICenter = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripSeparator1 = new System.Windows.Forms.ToolStripSeparator();
            this.toolStripMenuItem2 = new System.Windows.Forms.ToolStripMenuItem();
            this.tSMILargen = new System.Windows.Forms.ToolStripMenuItem();
            this.tSMISmaller = new System.Windows.Forms.ToolStripMenuItem();
            this.contextMenuStrip.SuspendLayout();
            this.SuspendLayout();
            // 
            // labelX1
            // 
            // 
            // 
            // 
            this.labelX1.BackgroundStyle.CornerType = DevComponents.DotNetBar.eCornerType.Square;
            this.labelX1.Location = new System.Drawing.Point(186, 100);
            this.labelX1.Name = "labelX1";
            this.labelX1.Size = new System.Drawing.Size(96, 23);
            this.labelX1.TabIndex = 0;
            this.labelX1.Text = "展示右键菜单";
            // 
            // contextMenuStrip
            // 
            this.contextMenuStrip.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem1,
            this.toolStripSeparator1,
            this.toolStripMenuItem2});
            this.contextMenuStrip.Name = "contextMenuStrip";
            this.contextMenuStrip.Size = new System.Drawing.Size(149, 54);
            // 
            // toolStripMenuItem1
            // 
            this.toolStripMenuItem1.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.tSMICenter});
            this.toolStripMenuItem1.Name = "toolStripMenuItem1";
            this.toolStripMenuItem1.Size = new System.Drawing.Size(148, 22);
            this.toolStripMenuItem1.Text = "窗体位置指令";
            // 
            // tSMICenter
            // 
            this.tSMICenter.Name = "tSMICenter";
            this.tSMICenter.Size = new System.Drawing.Size(180, 22);
            this.tSMICenter.Text = "窗体居中";
            this.tSMICenter.Click += new System.EventHandler(this.tSMICenter_Click);
            // 
            // toolStripSeparator1
            // 
            this.toolStripSeparator1.Name = "toolStripSeparator1";
            this.toolStripSeparator1.Size = new System.Drawing.Size(145, 6);
            // 
            // toolStripMenuItem2
            // 
            this.toolStripMenuItem2.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.tSMILargen,
            this.tSMISmaller});
            this.toolStripMenuItem2.Name = "toolStripMenuItem2";
            this.toolStripMenuItem2.Size = new System.Drawing.Size(148, 22);
            this.toolStripMenuItem2.Text = "窗体大小指令";
            // 
            // tSMILargen
            // 
            this.tSMILargen.Name = "tSMILargen";
            this.tSMILargen.Size = new System.Drawing.Size(124, 22);
            this.tSMILargen.Text = "窗体变大";
            this.tSMILargen.Click += new System.EventHandler(this.tSMILargen_Click);
            // 
            // tSMISmaller
            // 
            this.tSMISmaller.Name = "tSMISmaller";
            this.tSMISmaller.Size = new System.Drawing.Size(124, 22);
            this.tSMISmaller.Text = "窗体变小";
            this.tSMISmaller.Click += new System.EventHandler(this.tSMISmaller_Click);
            // 
            // frmContextmenu
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(484, 261);
            this.Controls.Add(this.labelX1);
            this.MaximizeBox = false;
            this.Name = "frmContextmenu";
            this.Text = "右键菜单";
            this.MouseClick += new System.Windows.Forms.MouseEventHandler(this.frmContextmenu_MouseClick);
            this.contextMenuStrip.ResumeLayout(false);
            this.ResumeLayout(false);

        }

        #endregion

        private DevComponents.DotNetBar.LabelX labelX1;
        private System.Windows.Forms.ContextMenuStrip contextMenuStrip;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem1;
        private System.Windows.Forms.ToolStripMenuItem tSMICenter;
        private System.Windows.Forms.ToolStripSeparator toolStripSeparator1;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem2;
        private System.Windows.Forms.ToolStripMenuItem tSMILargen;
        private System.Windows.Forms.ToolStripMenuItem tSMISmaller;
    }
}