asp.net文件上传解决方案（图片上传、单文件上传、多文件上传、检查文件类型）

2020-01-17 23:09:47

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小编之前也介绍了许多ASP.NET文件上传的解决案例，今天来个asp.net文件上传大集合。

1 使用标准HTML来进行图片上传
前台代码：

<body>  <form id="form1" runat="server">  <div>   <table>    <tr>     <td colspan="2" style="height: 21px" >      使用标准HTML来进行图片上传</td>    </tr>    <tr>     <td style="width: 400px">      <input id="InputFile" style="width: 399px" type="file" runat="server" /></td>     <td style="width: 80px">      <asp:Button ID="UploadButton" runat="server" Text="上传图片" OnClick="UploadButton_Click" /></td>    </tr>    <tr>     <td colspan="2" >      <asp:Label ID="Lb_Info" runat="server" ForeColor="Red"></asp:Label></td>        </tr>   </table>   </div>  </form> </body>

后台代码：

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; public partial class _Default : System.Web.UI.Page {  protected void Page_Load(object sender, EventArgs e)  {  }  protected void UploadButton_Click(object sender, EventArgs e)  {   string uploadName = InputFile.Value;//获取待上传图片的完整路径，包括文件名   //string uploadName = InputFile.PostedFile.FileName;   string pictureName = "";//上传后的图片名，以当前时间为文件名，确保文件名没有重复   if (InputFile.Value != "")   {    int idx = uploadName.LastIndexOf(".");    string suffix = uploadName.Substring(idx);//获得上传的图片的后缀名    pictureName = DateTime.Now.Ticks.ToString() + suffix;   }   try   {    if (uploadName != "")    {     string path = Server.MapPath("~/images/");     InputFile.PostedFile.SaveAs(path + pictureName);    }   }   catch (Exception ex)   {    Response.Write(ex);   }  } }

2 单文件上传
这是最基本的文件上传，在asp.net1.x中没有这个FileUpload控件，只有html的上传控件，那时候要把html控件转化为服务器控件，很不好用。其实所有文件上传的美丽效果都是从这个FileUpload控件衍生，第一个例子虽然简单却是根本。
前台代码：

<body>  <form id="form1" runat="server">  <div>   <table style="width: 90%">    <tr>     <td style="width: 159px" colspan=2>      <strong><span style="font-size: 10pt">最简单的单文件上传</span></strong></td>    </tr>    <tr>     <td style="width: 600px">      <asp:FileUpload ID="FileUpload1" runat="server" Width="600px" /></td>     <td align=left>      <asp:Button ID="FileUpload_Button" runat="server" Text="上传图片" OnClick="FileUpload_Button_Click" /></td>    </tr>    <tr>     <td colspan=2>      <asp:Label ID="Upload_info" runat="server" ForeColor="Red" Width="767px"></asp:Label></td>    </tr>   </table>   </div>  </form> </body>

后台代码：

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; public partial class _Default : System.Web.UI.Page {  protected void Page_Load(object sender, EventArgs e)  {  }  protected void FileUpload_Button_Click(object sender, EventArgs e)  {   try   {    if (FileUpload1.PostedFile.FileName == "")    //if (FileUpload1.FileName == "")    //if (!FileUpload1.HasFile)  //获取一个值，该值指示 System.Web.UI.WebControls.FileUpload 控件是否包含文件。包含文件，则为 true；否则为 false。    {     this.Upload_info.Text = "请选择上传文件！";    }    else    {     string filepath = FileUpload1.PostedFile.FileName; //得到的是文件的完整路径,包括文件名，如：C:/Documents and Settings/Administrator/My Documents/My Pictures/20022775_m.jpg     //string filepath = FileUpload1.FileName;    //得到上传的文件名20022775_m.jpg     string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);//20022775_m.jpg     string serverpath = Server.MapPath("~/images/") + filename;//取得文件在服务器上保存的位置C:/Inetpub/wwwroot/WebSite1/images/20022775_m.jpg     FileUpload1.PostedFile.SaveAs(serverpath);//将上传的文件另存为     this.Upload_info.Text = "上传成功！";    }   }   catch (Exception ex)   {    this.Upload_info.Text = "上传发生错误！原因是：" + ex.ToString();   }  } }

3、多文件上传
前台代码：

<body>  <form id="form1" runat="server">  <div>  <table style="width: 343px">    <tr>     <td style="width: 100px">      多文件上传</td>     <td style="width: 100px">     </td>    </tr>    <tr>     <td style="width: 100px">      <asp:FileUpload ID="FileUpload1" runat="server" Width="475px" />      </td>     <td style="width: 100px">      </td>    </tr>    <tr>     <td style="width: 100px">      <asp:FileUpload ID="FileUpload2" runat="server" Width="475px" /></td>     <td style="width: 100px">     </td>    </tr>    <tr>     <td style="width: 100px">      <asp:FileUpload ID="FileUpload3" runat="server" Width="475px" /></td>     <td style="width: 100px">     </td>    </tr>    <tr>     <td style="width: 100px">      <asp:Button ID="bt_upload" runat="server" OnClick="bt_upload_Click" Text="一起上传" />      <asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="448px"></asp:Label></td>     <td style="width: 100px">     </td>    </tr>   </table>  </div>  </form> </body>

后台代码：

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; public partial class _Default : System.Web.UI.Page {  protected void Page_Load(object sender, EventArgs e)  {  }  protected void bt_upload_Click(object sender, EventArgs e)  {   if (FileUpload1.PostedFile.FileName == "" && FileUpload2.PostedFile.FileName == "" && FileUpload3.PostedFile.FileName == "")   {    this.lb_info.Text = "请选择文件！";   }   else   {    HttpFileCollection myfiles = Request.Files;    for (int i = 0; i < myfiles.Count; i++)    {     HttpPostedFile mypost = myfiles[i];     try     {      if (mypost.ContentLength > 0)      {       string filepath = mypost.FileName;//C:/Documents and Settings/Administrator/My Documents/My Pictures/20022775_m.jpg       string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);//20022775_m.jpg       string serverpath = Server.MapPath("~/images/") + filename;//C:/Inetpub/wwwroot/WebSite2/images/20022775_m.jpg       mypost.SaveAs(serverpath);       this.lb_info.Text = "上传成功！";      }     }     catch (Exception ex)     {      this.lb_info.Text = "上传发生错误！原因：" + ex.Message.ToString();     }    }   }  } }

4、客户端检查上传文件类型(以上传图片为例)

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">  <title>客户端检查上传文件类型</title>  <script language="javascript">  function Check_FileType()  {   var str=document.getElementById("FileUpload1").value;   var pos=str.lastIndexOf(".");   var lastname=str.substring(pos,str.length);   if(lastname.toLowerCase()!=".jpg"&&lastname.toLowerCase()!=".gif")   {    alert("您上传的文件类型为"+lastname+"，图片必须为.jpg,.gif类型");    return false;   }   else   {    return true;   }    }  </script> </head> <body>  <form id="form1" runat="server">  <div>   <table>    <tr>     <td colspan="2">      客户端检查上传文件类型</td>        </tr>    <tr>     <td style="width: 444px">      <asp:FileUpload ID="FileUpload1" runat="server" Width="432px" /></td>     <td style="width: 80px">      <asp:Button ID="bt_upload" runat="server" Text="上传图片" OnClick="bt_upload_Click" OnClientClick="return Check_FileType()" /></td>    </tr>    <tr>     <td colspan="2" style="height: 21px">      <asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="515px"></asp:Label></td>        </tr>   </table>   </div>  </form> </body> </html>

注意：点击上传时先触发客户端事件OnClientClick="return Check_FileType()"

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; public partial class _Default : System.Web.UI.Page {  protected void Page_Load(object sender, EventArgs e)  {  }  protected void bt_upload_Click(object sender, EventArgs e)  {   try   {    if (FileUpload1.PostedFile.FileName == "")    {     this.lb_info.Text = "请选择文件！";    }    else    {     string filepath = FileUpload1.PostedFile.FileName;     //if (!IsAllowedExtension(FileUpload1))     //{     // this.lb_info.Text = "上传文件格式不正确！";     //}     if (IsAllowedExtension(FileUpload1) == true)     {      string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);      string serverpath = Server.MapPath("~/images/") + filename;      FileUpload1.PostedFile.SaveAs(serverpath);      this.lb_info.Text = "上传成功！";     }     else     {      this.lb_info.Text = "请上传图片！";     }    }   }   catch (Exception ex)   {    this.lb_info.Text = "上传发生错误！原因：" + ex.ToString();   }  }  private static bool IsAllowedExtension(FileUpload upfile)  {   string strOldFilePath = "";   string strExtension="";   string[] arrExtension ={ ".gif", ".jpg", ".bmp", ".png" };   if (upfile.PostedFile.FileName != string.Empty)   {    strOldFilePath = upfile.PostedFile.FileName;//获得文件的完整路径名    strExtension = strOldFilePath.Substring(strOldFilePath.LastIndexOf("."));//获得文件的扩展名，如：.jpg    for (int i = 0; i < arrExtension.Length; i++)    {     if (strExtension.Equals(arrExtension[i]))     {      return true;     }    }   }   return false;  } }

注意：若去掉客户端的脚本和客户端事件OnClientClick="return Check_FileType()"，在后台代码
改为：

if (!IsAllowedExtension(FileUpload1))     {      this.lb_info.Text = "上传文件格式不正确！";     }

else if (IsAllowedExtension(FileUpload1) == true)
即变成服务器端检查上传文件类型。
5、服务器端检查上传文件的类型（文件内部真正的格式）

<body>  <form id="form1" runat="server">  <div>   <table>    <tr>     <td colspan="2">      服务器检查上传文件类型</td>        </tr>    <tr>     <td style="width: 444px">      <asp:FileUpload ID="FileUpload1" runat="server" Width="432px" /></td>     <td style="width: 80px">      <asp:Button ID="bt_upload" runat="server" Text="上传图片" OnClick="bt_upload_Click" /></td>    </tr>    <tr>     <td colspan="2" style="height: 21px">      <asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="515px"></asp:Label></td>        </tr>   </table>   </div>  </form> </body>

后台代码：

using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; public partial class _Default : System.Web.UI.Page {  protected void Page_Load(object sender, EventArgs e)  {  }  protected void bt_upload_Click(object sender, EventArgs e)  {   try   {    if (FileUpload1.PostedFile.FileName == "")    {     this.lb_info.Text = "请选择文件！";    }    else    {     string filepath = FileUpload1.PostedFile.FileName;     if (IsAllowedExtension(FileUpload1) == true)     {      string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);      string serverpath = Server.MapPath("images/") + filename;      FileUpload1.PostedFile.SaveAs(serverpath);      this.lb_info.Text = "上传成功！";     }     else     {      this.lb_info.Text = "请上传图片";     }    }   }   catch (Exception error)   {    this.lb_info.Text = "上传发生错误！原因：" + error.ToString();   }  }  private static bool IsAllowedExtension(FileUpload upfile)  {   FileStream fs = new FileStream(upfile.PostedFile.FileName, FileMode.Open, FileAccess.Read);   BinaryReader r = new BinaryReader(fs);   string fileclass = "";   byte buffer;   try   {    buffer = r.ReadByte();    fileclass = buffer.ToString();    buffer = r.ReadByte();    fileclass += buffer.ToString();   }   catch   {       }   r.Close();   fs.Close();   if (fileclass == "255216" || fileclass == "7173"||fileclass=="6677"||fileclass=="13780")//说明255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar   {    return true;   }   else   {    return false;   }  } }

为大家推荐一个专题，供大家学习：《ASP.NET文件上传汇总》

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