C#实现外部图片的拖拽到应用程序的简单功能，附全部源码，供有需要的参考

通用权限管理系统组件源码里，有职员管理的功能，实现了直接可以把照片拖拽过来的功能，用起来会很方便。

管理软件能支持拖拽功能，会好用很多，用户体验也会改善很多。想做好一个组件需要把放放面面都彻底做好才可以。

想要控件支持拖拽，需要设置 AllowDrop 属性。

还需要写下面的2个事件。

参考代码如下，有需要的可以参考一下，把有需要的代码参考一下就可以了。

代码

//-----------------------------------------------------------

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Drawing;

using System.Data;

using System.Text;

using System.Windows.Forms;

using System.IO;

namespace DotNet.WinForm.File

{

using DotNet.Model;

using DotNet.Utilities;

using DotNet.Service;

/// <summary>

/// UCPicture

/// 照片显示控件

///

/// 修改纪录

///

/// 2010.12.08 版本：2.0 JiRiGaLa 更新员工更新照片的错误。

/// 2008.04.29 版本：1.0 JiRiGaLa 创建。

///

/// 版本：2.0

/// <author>

/// <name>JiRiGaLa</name>

/// <date>2010.12.08</date>

/// </author>

/// </summary>

public partial class UCPicture : UserControl

{

public UCPicture()

{

InitializeComponent();

}

private BaseUserInfo userInfo = new BaseUserInfo();

/// <summary>

/// 当前操作员信息

/// </summary>

public BaseUserInfo UserInfo

get

{

userInfo = new BaseUserInfo();

userInfo.GetUserInfo();

return userInfo;

}

set

userInfo = value;

/// 保存到数据库

public bool FromDatabase = true;

private string fileId = string.Empty;

public string FileId

return this.fileId;

this.fileId = value;

this.ShowPicture();

private string folderId = string.Empty;

public string FolderID

return this.folderId;

this.folderId = value;

private void UCPicture_Load(object sender, EventArgs e)

// 设置按钮状态

// this.SetControlState();

private void UCPicture_DragOver(object sender, DragEventArgs e)

if (e.Data.GetDataPresent(DataFormats.FileDrop))

e.Effect = DragDropEffects.Move;

private void UCPicture_DragDrop(object sender, DragEventArgs e)

string[] file = (string[])e.Data.GetData(DataFormats.FileDrop);

for (int i = 0; i <= file.Length - 1; i++)

{

if (System.IO.File.Exists(file[i]))

{

this.fileId = string.Empty;

// 设置显示的图片

this.pic.ImageLocation = file[i];

// 设置按钮状态

this.SetControlState();

break;

}

/// 显示图片

public void ShowPicture()

if (!String.IsNullOrEmpty(this.FileId))

// 显示图片

this.ShowPicture(this.FileId);

else

// 清除图片

this.ClearPicture();

/// <param name="id">主键</param>

private void ShowPicture(string id)

if (!this.FromDatabase)

this.pic.ImageLocation = BaseSystemInfo.StartupPath + id;

byte[] fileContent = null;

fileContent = this.Download(id);

if (fileContent != null)

// this.pic.Image = this.ByteToImage(fileContent);

MemoryStream memoryStream = new MemoryStream(fileContent);

Bitmap bitmap = new Bitmap(memoryStream);

this.pic.Image = bitmap;

else

this.FileId = string.Empty;

this.ClearPicture();

this.SetControlState();

/// 从数据库中读取文件

/// <param name="id">文件主键</param>

/// <returns>文件</returns>

public byte[] Download(string id)

return ServiceManager.Instance.FileService.Download(UserInfo, id);

// OleDbHelper dbHelper = new SqlHelper();

// dbHelper.Open();

// byte[] fileContent = null;

// string sqlQuery = " SELECT " + BaseFileTable.FieldFileContent

// + " FROM " + BaseFileTable.TableName

// + " WHERE " + BaseFileTable.FieldId + " = '" + Id + "'";

// OleDbDataReader dataReader = (OleDbDataReader)dbHelper.ExecuteReader(sqlQuery);

// if (dataReader.Read())

// {

// fileContent = (byte[])dataReader[BaseFileTable.FieldFileContent];

// }

// dbHelper.Close();

// return fileContent;

public string Upload(string folderId, string categoryId)

this.FolderID = folderId;

string returnValue = string.Empty;

if (!String.IsNullOrEmpty(this.pic.ImageLocation))

// 保存到数据库

if (this.FromDatabase)

if (String.IsNullOrEmpty(this.FileId))

returnValue = ServiceManager.Instance.FileService.Upload(UserInfo, folderId, Path.GetFileName(this.pic.ImageLocation), FileUtil.GetFile(this.pic.ImageLocation), true);

else

string statusCode = string.Empty;

string statusMessage = string.Empty;

ServiceManager.Instance.FileService.UpdateFile(UserInfo, this.FileId, Path.GetFileName(this.pic.ImageLocation), FileUtil.GetFile(this.pic.ImageLocation), out statusCode, out statusMessage);

returnValue = this.FileId;

// 复制文件到指定的目录里

if (!this.pic.ImageLocation.Equals(BaseSystemInfo.StartupPath + this.FileId))

string destDirectory = BaseSystemInfo.StartupPath + "\\UploadFiles" + "\\" + folderId + "\\" + categoryId;

System.IO.Directory.CreateDirectory(destDirectory);

string destFileName = destDirectory + "\\" + Path.GetFileName(this.pic.ImageLocation);

System.IO.File.Copy(this.pic.ImageLocation, destFileName);

returnValue = "\\UploadFiles" + "\\" + folderId + "\\" + categoryId + "\\" + Path.GetFileName(this.pic.ImageLocation);

// OleDbHelper dbHelper = new SqlHelper();

// dbHelper.Open();

// string sequence = BaseSequenceManager.Instance.GetSequence(DbHelper, BaseFileTable.TableName);

// OleDbSQLBuilder sqlBuilder = new OleDbSQLBuilder();

// sqlBuilder.BeginInsert(DbHelper, BaseFileTable.TableName);

// sqlBuilder.SetValue(BaseFileTable.FieldId, sequence);

// sqlBuilder.SetValue(BaseFileTable.FieldFolderId, folderId);

// sqlBuilder.SetValue(BaseFileTable.FieldFileName, Path.GetFileName(this.pic.ImageLocation));

// // byte[] File = this.ImageToByte(this.pic.Image);

// byte[] File = this.GetFile(this.pic.ImageLocation);

// sqlBuilder.SetValue(BaseFileTable.FieldFileContent, File);

// sqlBuilder.SetValue(BaseFileTable.FieldFileSize, File.Length);

// sqlBuilder.SetValue(BaseFileTable.FieldCreateUserId, UserInfo.Id);

// sqlBuilder.SetDBNow(BaseFileTable.FieldCreateDate);

// sqlBuilder.EndInsert();

// dbHelper.Close();

// returnValue = sequence;

return returnValue;

private void SetControlState(bool enabled)

this.btnSelect.Enabled = enabled;

this.btnClear.Enabled = enabled;

this.btnDelete.Enabled = enabled;

#region private void SetControlState() 设置按钮状态

/// 设置按钮状态

private void SetControlState()

this.btnSelect.Enabled = true;

// 是从数据库里面读取出来的

if (!String.IsNullOrEmpty(this.FileId) && (String.IsNullOrEmpty(this.pic.ImageLocation) || !this.FromDatabase))

this.btnDelete.Enabled = true;

this.btnDelete.Enabled = false;

// 清除按钮

this.btnClear.Enabled = false;

this.btnClear.Enabled = true;

this.btnDelete.Enabled = false;

this.btnClear.Enabled = true;

this.btnDelete.Enabled = false;

#endregion

private void pic_DoubleClick(object sender, EventArgs e)

if (this.pic.Image != null)

FrmPicture frmPicture = new FrmPicture(this.FileId);

frmPicture.SetImage(this.pic.Image);

frmPicture.Show();

}

private void btnSelect_Click(object sender, EventArgs e)

OpenFileDialog openFileDialog = new OpenFileDialog();

// OpenFileDialog.InitialDirectory = Application.StartupPath;

openFileDialog.FilterIndex = 7;

openFileDialog.RestoreDirectory = true;

openFileDialog.Title = "打开图片文件";

if (openFileDialog.ShowDialog() == DialogResult.OK)

this.fileId = string.Empty;

this.SetControlState(false);

this.pic.ImageLocation = openFileDialog.FileName;

// 设置按钮状态

this.SetControlState();

/// 清除图片

private void ClearPicture()

this.pic.ImageLocation = string.Empty;

this.pic.Image = null;

private void btnClear_Click(object sender, EventArgs e)

this.ClearPicture();

this.ShowPicture();

/// 删除文件

/// <returns>影响的行数</returns>

public int DeleteFile(string id)

int returnValue = 0;

if (this.FromDatabase)

// 从数据库服务器删除文件

returnValue = ServiceManager.Instance.FileService.Delete(UserInfo, id);

// 删除文件

System.IO.File.Delete(BaseSystemInfo.StartupPath + this.FileId);

private void btnDelete_Click(object sender, EventArgs e)

if (MessageBox.Show(AppMessage.MSG0207, AppMessage.MSG0000, MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2) == DialogResult.OK)

this.DeleteFile(this.FileId);

this.FileId = string.Empty;

}

本文转自jirigala_bao 51CTO博客，原文链接:http://blog.51cto.com/jirigala/809334

C#实现外部图片的拖拽到应用程序的简单功能，附全部源码，供有需要的参考

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