应用程序实现文件拖拉

本来没准备发这个基本的东西的.但有好多网友问这个问题,就写了个例子.以此抛砖引玉.

一个图片浏览器,可以实现在程序运行当中,直接拉入图片文件到程序窗口中打开.也可以在未打开的程序,将文件直接拖到程序图标上打开该图片文件.

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

namespace AllowDragFormTest
{
 /// <summary>
 /// 图片浏览器
///程序：房客
///网址：http://www.cnblogs.com/sxlfybb/
///转载请保留，谢谢
 /// </summary>
 public class Form1 : System.Windows.Forms.Form
 {
  /// <summary>
  /// 必需的设计器变量。
  /// </summary>
  private System.ComponentModel.Container components = null;
  private System.Windows.Forms.MainMenu mainMenu1;
  private System.Windows.Forms.MenuItem menuItem1;
  private System.Windows.Forms.MenuItem menuItem2;
  private System.Windows.Forms.MenuItem menuItem3;
  private System.Windows.Forms.MenuItem menuItem4;
  private System.Windows.Forms.OpenFileDialog openFileDialog1;
  private string strFilePath = string.Empty;
  private System.Windows.Forms.MenuItem menuItem5;
  private System.Windows.Forms.MenuItem menuItem6;
  private Image image = null;

  public Form1(string str)
  {
   //
   // Windows 窗体设计器支持所必需的
   //
   InitializeComponent();

   this.strFilePath = str;
   SetPicToBground();

   //
   // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
   //
  }

  public Form1()
  {
   InitializeComponent();
  }

  /// <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.mainMenu1 = new System.Windows.Forms.MainMenu();
   this.menuItem1 = new System.Windows.Forms.MenuItem();
   this.menuItem2 = new System.Windows.Forms.MenuItem();
   this.menuItem3 = new System.Windows.Forms.MenuItem();
   this.menuItem4 = new System.Windows.Forms.MenuItem();
   this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
   this.menuItem5 = new System.Windows.Forms.MenuItem();
   this.menuItem6 = new System.Windows.Forms.MenuItem();
   //
   // mainMenu1
   //
   this.mainMenu1.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {
                       this.menuItem1,
                       this.menuItem5});
   //
   // menuItem1
   //
   this.menuItem1.Index = 0;
   this.menuItem1.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {
                       this.menuItem2,
                       this.menuItem3,
                       this.menuItem4});
   this.menuItem1.Text = "文件(&F)";
   //
   // menuItem2
   //
   this.menuItem2.Index = 0;
   this.menuItem2.Text = "打开(&O)";
   this.menuItem2.Click += new System.EventHandler(this.menuItem2_Click);
   //
   // menuItem3
   //
   this.menuItem3.Index = 1;
   this.menuItem3.Text = "-";
   //
   // menuItem4
   //
   this.menuItem4.Index = 2;
   this.menuItem4.Text = "退出(&X)";
   this.menuItem4.Click += new System.EventHandler(this.menuItem4_Click);
   //
   // menuItem5
   //
   this.menuItem5.Index = 1;
   this.menuItem5.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {
                       this.menuItem6});
   this.menuItem5.Text = "帮助(&H)";
   //
   // menuItem6
   //
   this.menuItem6.Index = 0;
   this.menuItem6.Text = "关于(&A)";
   this.menuItem6.Click += new System.EventHandler(this.menuItem6_Click);
   //
   // Form1
   //
   this.AllowDrop = true;
   this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
   this.ClientSize = new System.Drawing.Size(296, 245);
   this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
   this.MaximizeBox = false;
   this.Menu = this.mainMenu1;
   this.Name = "Form1";
   this.Text = "图片浏览器";

  }
  #endregion

  /// <summary>
  /// 应用程序的主入口点。
   ///直接拖拉文件到程序的图标上
  /// </summary>
  [STAThread]
  static void Main(string[] args)
  {
   if( args.Length >0 )
   {
    //如果是拉入文件打开的程序
    Application.Run(new Form1(args[0]));
   }
   else
   //直接打开程序
    Application.Run(new Form1());
  }

  private void menuItem2_Click(object sender, System.EventArgs e)
  {
   openFileDialog1.Filter = "图像文件|*.jpg;*.jpeg;*.bmp;*.gif";
   if (openFileDialog1.ShowDialog(this) == DialogResult.OK)
   {
    this.strFilePath = openFileDialog1.FileName;
    SetPicToBground();
   }
  }

  private void SetPicToBground()
  {
   try
   {
    FileInfo file = new FileInfo(strFilePath);
    if (file.Exists)
    {
     if (image != null)
      image = null;
     image = Image.FromFile(strFilePath,true);
      this.Width = image.Width;
      this.Height = image.Height;
      this.BackgroundImage = image;
    }
   }
   catch( Exception ex)
   {
    MessageBox.Show(ex.Message);
   }
  }

//正在运行的程序中,接收拖拉入的文件.

  protected override void OnDragEnter(DragEventArgs e)
  {
   if( e.Data.GetDataPresent(DataFormats.Bitmap,true) || e.Data.GetDataPresent(DataFormats.FileDrop))
   {
    e.Effect = DragDropEffects.Link;
   }
   else
   {
    e.Effect = DragDropEffects.None;
   }
  }

  protected override void OnDragDrop(DragEventArgs e)
  {
   if( e.Data.GetDataPresent(DataFormats.FileDrop) )
   {
    string[] strs = (string[])e.Data.GetData(DataFormats.FileDrop);
    if( strs.Length >0 )
    {
     this.strFilePath = strs[0];
     SetPicToBground();
    }

   }
  }

  private void menuItem4_Click(object sender, System.EventArgs e)
  {
   Application.Exit();
  }

  private void menuItem6_Click(object sender, System.EventArgs e)
  {
   string  str = "图片浏览器 Ver1.0" ;
   str += System.Environment.NewLine;
   str += System.Environment.NewLine;
   str += "程序：房客 " + "\t" + "QQ：83849123";

   MessageBox.Show( this,str,"信息",MessageBoxButtons.OK,MessageBoxIcon.Information );

  }
 }
}