用C#实现在ListBox中拖动排序

用C#实现在ListBox中拖动排序

现在在C#中处理有关的拖放操作变得比以前方便多了，现在就已一个例子说明，这个例子演示了通过鼠标的拖动在一个ListBox中进行排序操作。

相关源码如下：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace WindowsApplication2
...{
    public class Form1 : System.Windows.Forms.Form
    ...{
        private System.Windows.Forms.ListBox listBox1;
        int indexofsource;//拖动的起始索引
        int indexoftarget; //拖动的结束索引
        private System.ComponentModel.Container components = null;
        public Form1()
        ...{
            InitializeComponent();
        }

        protected override void Dispose(bool disposing)
        ...{
            if (disposing)
            ...{
                if (components != null)
                ...{
                    components.Dispose();
                }
            }
            base.Dispose(disposing);
        }

        Windows 窗体设计器生成的代码#region Windows 窗体设计器生成的代码

        private void InitializeComponent()
        ...{
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            //
            // listBox1
            //
            this.listBox1.AllowDrop = true;//这个属性一定要设置为true;
            this.listBox1.ItemHeight = 12;
            this.listBox1.Items.AddRange(new object[] ...{
                "1",
                "2",
                "3",
                "4",
                "5",
                "6",
                "7",
                "8",
                "9",
                "0"});
            this.listBox1.Location = new System.Drawing.Point(16, 8);
            this.listBox1.Name = "listBox1";
            this.listBox1.ScrollAlwaysVisible = true;
            this.listBox1.Size = new System.Drawing.Size(264, 136);
            this.listBox1.TabIndex = 0;
            this.listBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.listBox1_MouseDown);
            this.listBox1.DragOver += new System.Windows.Forms.DragEventHandler(this.listBox1_DragOver);
            this.listBox1.DragDrop += new System.Windows.Forms.DragEventHandler(this.listBox1_DragDrop);
            this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Controls.Add(this.listBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
        }

        #endregion

        [STAThread]
        static void Main()
        ...{
            Application.Run(new Form1());
        }

        private void listBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
        ...{
            indexofsource = ((ListBox)sender).IndexFromPoint(e.X, e.Y);
            if (indexofsource != ListBox.NoMatches)
            ...{
                ((ListBox)sender).DoDragDrop(((ListBox)sender).Items[indexofsource].ToString(), DragDropEffects.All);
            }
        }

        private void listBox1_DragOver(object sender, System.Windows.Forms.DragEventArgs e)
        ...{ //拖动源和放置的目的地一定是一个ListBox
            if (e.Data.GetDataPresent(typeof(System.String)) && ((ListBox)sender).Equals(listBox1))
            ...{
                e.Effect = DragDropEffects.Move;
            }
            else
                e.Effect = DragDropEffects.None;
        }

        private void listBox1_DragDrop(object sender, System.Windows.Forms.DragEventArgs e)
        ...{
            ListBox listbox = (ListBox)sender;
            indexoftarget = listbox.IndexFromPoint(listbox.PointToClient(new Point(e.X, e.Y)));
            if (indexoftarget != ListBox.NoMatches)
            ...{
                string temp = listbox.Items[indexoftarget].ToString();
                listbox.Items[indexoftarget] = listbox.Items[indexofsource];
                listbox.Items[indexofsource] = temp;
                listbox.SelectedIndex = indexoftarget;
            }
        }
    }

}
好了，现在我们的目标达到了。我们还可以通过处理QueryContinueDrag、GiveFeedback事件获得更多的功能。