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用C#.NET实现拖放操作

技术2022-05-11  1


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在应用程序中,是通过处理一系列事件,如DragEnter,DragLeave和DragDrop事件来实现在Windows应用程序中的拖放操作的。通过使用这些事件参数中的可用信息,可以轻松实现拖放操作。拖放操作在代码中是通过三步实现的,首先是启动拖放操作,在需要拖动数据的控件上实现MouseDown事件响应代码,并调用DoDragDrop()方法;其次是实现拖放效果,在目标控件上添加DragEnter事件响应代码,使用DragDropEffects枚举类型实现移动或复制等拖动效果;最后是放置数据操作,在目标控件上添加DragDrop响应代码,把数据添加到目标控件中。

using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Data; namespace DragDrop { /// <summary> /// Form1 的摘要说明。 /// </summary> public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.ListBox listBox1; private System.Windows.Forms.ListBox listBox2; /// <summary> /// 必需的设计器变量。 /// </summary> private System.ComponentModel.Container components = null; public Form1() { // // Windows 窗体设计器支持所必需的 // InitializeComponent(); // // TODO: 在 InitializeComponent 调用后添加任何构造函数代码 // } /// <summary> /// 清理所有正在使用的资源。 /// </summary> protected override void Dispose( bool disposing ) { if( disposing ) { if (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 - 不要使用代码编辑器修改 /// 此方法的内容。 /// </summary> private void InitializeComponent() { this.listBox1 = new System.Windows.Forms.ListBox(); this.listBox2 = new System.Windows.Forms.ListBox(); this.SuspendLayout(); // // listBox1 // this.listBox1.ItemHeight = 12; this.listBox1.Location = new System.Drawing.Point(32, 24); this.listBox1.Name = "listBox1"; this.listBox1.Size = new System.Drawing.Size(120, 280); this.listBox1.TabIndex = 0; this.listBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.listBox1_MouseDown); // // listBox2 // this.listBox2.ItemHeight = 12; this.listBox2.Location = new System.Drawing.Point(248, 24); this.listBox2.Name = "listBox2"; this.listBox2.Size = new System.Drawing.Size(120, 280); this.listBox2.TabIndex = 0; this.listBox2.DragDrop += new System.Windows.Forms.DragEventHandler(this.listBox2_DragDrop); this.listBox2.DragEnter += new System.Windows.Forms.DragEventHandler(this.listBox2_DragEnter); // // Form1 // this.AutoScaleBaseSize = new System.Drawing.Size(6, 14); this.ClientSize = new System.Drawing.Size(408, 333); this.Controls.Add(this.listBox1); this.Controls.Add(this.listBox2); this.Name = "Form1"; this.Text = "Form1"; this.Load += new System.EventHandler(this.Form1_Load); this.ResumeLayout(false); } #endregion /// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() { Application.Run(new Form1()); } private void Form1_Load(object sender, System.EventArgs e) { this.listBox1.AllowDrop = true; this.listBox2.AllowDrop = true; this.listBox1.Items.Add("a"); this.listBox1.Items.Add("b"); this.listBox1.Items.Add("c"); } private void listBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) { this.listBox1.DoDragDrop(this.listBox1.Items[this.listBox1.SelectedIndex],DragDropEffects.Move); } private void listBox2_DragEnter(object sender, System.Windows.Forms.DragEventArgs e) { if(e.Data.GetDataPresent("Text")) { e.Effect = DragDropEffects.Move; } } private void listBox2_DragDrop(object sender, System.Windows.Forms.DragEventArgs e) { this.listBox2.Items.Add(e.Data.GetData("Text")); this.listBox1.Items.Remove(e.Data.GetData("Text")); } } } 资料引用:http://www.knowsky.com/339953.html


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