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("\\") + );//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 = ; i < myfiles.Count; i++)
{
HttpPostedFile mypost = myfiles[i];
try
{
if (mypost.ContentLength > )
{
string filepath = mypost.FileName;//C:\Documents and Settings\Administrator\My Documents\My Pictures\20022775_m.jpg
string filename = filepath.Substring(filepath.LastIndexOf("\\") + );//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("\\") + );
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 = ; 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("\\") + );
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 == "" || fileclass == ""||fileclass==""||fileclass=="")//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;
}
}
}
转自： http://blog.csdn.net/qing0991/archive/2008/09/06/2890654.aspx