asp.net 模拟提交有文件上传的表单(通过http模拟上传文件)

<form action="sql.aspx" method="post" enctype="multipart/form-data"> 
<input id="Text1" name="content" type="text" /><br /> 
<input id="Text2" name="uploadImg" type="text" /><br /> 
<input id="File1" type="file" name="image0" /><br /> 
<input id="Submit1" type="submit" value="submit" /> 
</form> 
 
为了查看表单提交时，向服务端post了什么数据，这里我使用Fiddler来查看。Fiddler确实是个不错的工具，注意当url主机地址是localhost时Fiddler捕获不到，需要再localhost后加一点(.)即可，打开Fiddler，浏览带上面form的page，输入数据提交，此时在Fiddler中可看到post的数据了。下面是一部份数据的截图。 

分析其中的数据不难得出，一个表单中的数据域(input type="text")对应的格式为 

-----------------------------7da119c1004a6 
Content-Disposition: form-data; name="content" 

this is a txt value 
一个文件(input type="file")对应的格式为(通常为表单最后一个参数) 

-----------------------------7da119c1004a6 
Content-Disposition: form-data; name="image0"; filename="E:\CAI\875.jpg" 
Content-Type: image/pjpeg 

[文件内容] 
结尾处是-----------------------------7da119c1004a6-- 



有了上面的数据做参考，按照其格式组织数据，post到服务端，同样可以达到html form提交的效果。要特别注意其格式：如回车换行，差一个都可能得不到正确的响应，还有请求的Content-Length一定计算对。下面是一个参考： 

代码 
 代码如下:

public string POSTfile(string v1,string v2, string file) 
{ 
string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x"); 

//请求 
WebRequest req = WebRequest.Create(@"http://localhost.:4944/WebSite1/getfile.aspx"); 
req.Method = "POST"; 
req.ContentType = "multipart/form-data; boundary=" + boundary; 

//组织表单数据 
StringBuilder sb = new StringBuilder(); 
sb.Append("--" + boundary); 
sb.Append("\r\n"); 
sb.Append("Content-Disposition: form-data; name=\"content\""); 
sb.Append("\r\n\r\n"); 
sb.Append(v1); 
sb.Append("\r\n"); 

sb.Append("--" + boundary); 
sb.Append("\r\n"); 
sb.Append("Content-Disposition: form-data; name=\"uploadImg\""); 
sb.Append("\r\n\r\n"); 
sb.Append("v2"); 
sb.Append("\r\n"); 

sb.Append("--" + boundary); 
sb.Append("\r\n"); 
sb.Append("Content-Disposition: form-data; name=\"image0\"; filename=\"e:\\a.jpg\""); 
sb.Append("\r\n"); 
sb.Append("Content-Type: image/pjpeg"); 
sb.Append("\r\n\r\n"); 

string head = sb.ToString(); 
byte[] form_data = Encoding.UTF8.GetBytes(head); 
//结尾 
byte[] foot_data = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n"); 

//文件 
FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read); 
//post总长度 
long length = form_data.Length + fileStream.Length + foot_data.Length; 
req.ContentLength = length; 

Stream requestStream = req.GetRequestStream(); 
//发送表单参数 
requestStream.Write(form_data, 0, form_data.Length); 
//文件内容 
byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)fileStream.Length))]; 
int bytesRead = 0; 
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) 
requestStream.Write(buffer, 0, bytesRead); 
//结尾 
requestStream.Write(foot_data, 0, foot_data.Length); 
requestStream.Close(); 

//响应 
WebResponse pos = req.GetResponse(); 
StreamReader sr = new StreamReader(pos.GetResponseStream(), Encoding.UTF8); 
string html = sr.ReadToEnd().Trim(); 
sr.Close(); 
if (pos != null) 
{ 
pos.Close(); 
pos = null; 
} 
if (req != null) 
{ 
req = null; 
} 
return html; 
}