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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）

程序员文章站 2023-12-20 19:49:40
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：

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》

是不是内容很精彩，喜欢的朋友就收藏起来吧，以后在遇到asp.net文件上传问题的时候能够有所帮助。

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