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(<
c9f0
/span>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。