Asp.Net模拟表单提交数据和上传文件的实现代码

如果你需要跨域上传内容到另外一个域名并且需要获取返回值，使用Asp.Net的作为代理是最好的办法，要是客户端直接提交到iframe中，由于跨域是无法用javascript获取到iframe中返回的内容的。此时需要在自己的网站做一个动态页作为代理，将表单提交到动态页，动态页负责将表单的内容使用WebClient或HttpWebRequest将表单数据再上传到远程服务器，由于在服务器端进行操作，就不存在跨域问题了。

WebClient上传只包含键值对的文本信息示例代码：

复制代码代码如下:
string uriString = "http://localhost/login.aspx";
// 创建一个新的 WebClient 实例.
WebClient myWebClient = new WebClient（）;
string postData = "Username=admin&Password=admin";
// 注意这种拼字符串的ContentType
myWebClient.Headers.Add（"Content-Type","application/x-www-form-urlencoded"）;
// 转化成二进制数组
byte[] byteArray = Encoding.ASCII.GetBytes（postData）;
// 上传数据，并获取返回的二进制数据.
byte[] responseArray = myWebClient.UploadData（uriString,"POST",byteArray）;

WebClient上传只包含文件的示例代码：

复制代码代码如下:
String uriString = "http://localhost/uploadFile.aspx";
// 创建一个新的 WebClient 实例.
WebClient myWebClient = new WebClient（）;
string fileName = @"C:/upload.txt";
// 直接上传，并获取返回的二进制数据.
byte[] responseArray = myWebClient.UploadFile（uriString,"POST",fileName）;

对于既包含文件又包含文本键值对信息的示例代码，需要构造表单提交的内容，对于学asp的同学来说，下面的表单提交内容一定不会陌生
复制代码代码如下:
-----------------------------7d429871607fe
Content-Disposition: form-data; name="file1"; filename="G:/homepage.txt"
Content-Type: text/plain
脚本之家：http://www.jb51.net
-----------------------------7d429871607fe
Content-Disposition: form-data; name="filename"
default filename
-----------------------------7d429871607fe--

所以只要拼一个这样的byte[] data数据Post过去，就可以达到同样的效果了。但是一定要注意，对于这种带有文件上传的，其ContentType是不一样的，例如上面的这种，其ContentType为"multipart/form-data; boundary=---------------------------7d429871607fe"。有了ContentType，我们就可以知道boundary（就是上面的"---------------------------7d429871607fe"），知道boundary了我们就可以构造出我们所需要的byte[] data了，最后，不要忘记，把我们构造的ContentType传到WebClient中（例如:webClient.Headers.Add（"Content-Type", ContentType）;）这样，就可以通过WebClient.UploadData 方法上载文件数据了。

using System;using System.Web;using System.IO;using System.Net;using System.Text;using System.Collections;namespace UploadData.Common{public class CreateBytes{Encoding encoding = Encoding.UTF8;public byte[] JoinBytes（ArrayList byteArrays）{int length = 0;int readLength = 0;// 加上结束边界string endBoundary = Boundary + "-- ";byte[] endBoundaryBytes = encoding.GetBytes（endBoundary）;byteArrays.Add（endBoundaryBytes）;foreach （byte[] b in byteArrays）{length += b.Length;}byte[] bytes = new byte[length];// 遍历复制foreach （byte[] b in byteArrays）{b.CopyTo（bytes, readLength）;readLength += b.Length;}return bytes;}public bool UploadData（string uploadUrl, byte[] bytes, out byte[] responseBytes）{WebClient webClient = new WebClient（）;webClient.Headers.Add（"Content-Type", ContentType）;try{responseBytes = webClient.UploadData（uploadUrl, bytes）;return true;}catch （WebException ex）{Stream resp = ex.Response.GetResponseStream（）;responseBytes = new byte[ex.Response.ContentLength];resp.Read（responseBytes, 0, responseBytes.Length）;}return false;}/// 获取普通表单区域二进制数组public byte[] CreateFieldData（string fieldName, string fieldValue）{string textTemplate = Boundary + " Content-Disposition: form-data; name="{0}" {1} ";string text = String.Format（textTemplate, fieldName, fieldValue）;byte[] bytes = encoding.GetBytes（text）;return bytes;}public byte[] CreateFieldData（string fieldName, string filename, string contentType, byte[] fileBytes）{string end = " ";string textTemplate = Boundary + " Content-Disposition: form-data; name="{0}"; filename="{1}" Content-Type: {2} ";// 头数据string data = String.Format（textTemplate, fieldName, filename, contentType）;byte[] bytes = encoding.GetBytes（data）;// 尾数据byte[] endBytes = encoding.GetBytes（end）;// 合成后的数组byte[] fieldData = new byte[bytes.Length + fileBytes.Length + endBytes.Length];bytes.CopyTo（fieldData, 0）; // 头数据fileBytes.CopyTo（fieldData, bytes.Length）; // 文件的二进制数据endBytes.CopyTo（fieldData, bytes.Length + fileBytes.Length）; // return fieldData;}public string Boundary{get{string[] bArray, ctArray;string contentType = ContentType;ctArray = contentType.Split（";"）;if （ctArray[0].Trim（）.ToLower（） == "multipart/form-data"）{bArray = ctArray[1].Split（"="）;return "--" + bArray[1];}return null;}}public string ContentType{get{if （HttpContext.Current == null）{return "multipart/form-data; boundary=---------------------------7d5b915500cee";}return HttpContext.Current.Request.ContentType;}}}}using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;using UploadData.Common;using System.IO;namespace UploadDataWin{public class frmUpload : System.Windows.Forms.Form{private System.Windows.Forms.Label lblAmigoToken;private System.Windows.Forms.TextBox txtAmigoToken;private System.Windows.Forms.Label lblFilename;private System.Windows.Forms.TextBox txtFilename;private System.Windows.Forms.Button btnBrowse;private System.Windows.Forms.TextBox txtFileData;private System.Windows.Forms.Label lblFileData;private System.Windows.Forms.Button btnUpload;private System.Windows.Forms.OpenFileDialog openFileDialog1;private System.Windows.Forms.TextBox txtResponse;private System.ComponentModel.Container components = null;public frmUpload（）{InitializeComponent（）;}protected override void Dispose（bool disposing）{if （disposing）{if （components ！= null）{components.Dispose（）;}}base.Dispose（disposing）;}private void InitializeComponent（）{this.lblAmigoToken = new System.Windows.Forms.Label（）;this.txtAmigoToken = new System.Windows.Forms.TextBox（）;this.lblFilename = new System.Windows.Forms.Label（）;this.txtFilename = new System.Windows.Forms.TextBox（）;this.btnBrowse = new System.Windows.Forms.Button（）;this.txtFileData = new System.Windows.Forms.TextBox（）;this.lblFileData = new System.Windows.Forms.Label（）;this.btnUpload = new System.Windows.Forms.Button（）;this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog（）;this.txtResponse = new System.Windows.Forms.TextBox（）;this.SuspendLayout（）;// // lblAmigoToken// this.lblAmigoToken.Location = new System.Drawing.Point（40, 48）;this.lblAmigoToken.Name = "lblAmigoToken";this.lblAmigoToken.Size = new System.Drawing.Size（72, 23）;this.lblAmigoToken.TabIndex = 0;this.lblAmigoToken.Text = "AmigoToken";// // txtAmigoToken// this.txtAmigoToken.Location = new System.Drawing.Point（120, 48）;this.txtAmigoToken.Name = "txtAmigoToken";this.txtAmigoToken.Size = new System.Drawing.Size（248, 21）;this.txtAmigoToken.TabIndex = 1;this.txtAmigoToken.Text = "";// // lblFilename// this.lblFilename.Location = new System.Drawing.Point（40, 96）;this.lblFilename.Name = "lblFilename";this.lblFilename.Size = new System.Drawing.Size（80, 23）;this.lblFilename.TabIndex = 2;this.lblFilename.Text = "Filename";// // txtFilename// this.txtFilename.Location = new System.Drawing.Point（120, 96）;this.txtFilename.Name = "txtFilename";this.txtFilename.Size = new System.Drawing.Size（248, 21）;this.txtFilename.TabIndex = 3;this.txtFilename.Text = "";// // btnBrowse// this.btnBrowse.Location = new System.Drawing.Point（296, 144）;this.btnBrowse.Name = "btnBrowse";this.btnBrowse.TabIndex = 4;this.btnBrowse.Text = "浏览";this.btnBrowse.Click += new System.EventHandler（this.btnBrowse_Click）;// // txtFileData// this.txtFileData.Location = new System.Drawing.Point（120, 144）;this.txtFileData.Name = "txtFileData";this.txtFileData.Size = new System.Drawing.Size（168, 21）;this.txtFileData.TabIndex = 5;this.txtFileData.Text = "";// // lblFileData// this.lblFileData.Location = new System.Drawing.Point（40, 144）;this.lblFileData.Name = "lblFileData";this.lblFileData.Size = new System.Drawing.Size（72, 23）;this.lblFileData.TabIndex = 6;this.lblFileData.Text = "FileData";// // btnUpload// this.btnUpload.Location = new System.Drawing.Point（48, 184）;this.btnUpload.Name = "btnUpload";this.btnUpload.TabIndex = 7;this.btnUpload.Text = "Upload";this.btnUpload.Click += new System.EventHandler（this.btnUpload_Click）;// // txtResponse// this.txtResponse.Location = new System.Drawing.Point（136, 184）;this.txtResponse.Multiline = true;this.txtResponse.Name = "txtResponse";this.txtResponse.Size = new System.Drawing.Size（248, 72）;this.txtResponse.TabIndex = 8;this.txtResponse.Text = "";// // frmUpload// this.AutoScaleBaseSize = new System.Drawing.Size（6, 14）;this.ClientSize = new System.Drawing.Size（400, 269）;this.Controls.Add（this.txtResponse）;this.Controls.Add（this.btnUpload）;this.Controls.Add（this.lblFileData）;this.Controls.Add（this.txtFileData）;this.Controls.Add（this.btnBrowse）;this.Controls.Add（this.txtFilename）;this.Controls.Add（this.lblFilename）;this.Controls.Add（this.txtAmigoToken）;this.Controls.Add（this.lblAmigoToken）;this.Name = "frmUpload";this.Text = "frmUpload";this.ResumeLayout（false）;}[STAThread]static void Main（）{Application.Run（new frmUpload（））;}private void btnUpload_Click（object sender, System.EventArgs e）{// 非空检验if （txtAmigoToken.Text.Trim（） == "" || txtFilename.Text == "" || txtFileData.Text.Trim（） == ""）{MessageBox.Show（"Please fill data"）;return;}// 所要上传的文件路径string path = txtFileData.Text.Trim（）;// 检查文件是否存在if （！File.Exists（path））{MessageBox.Show（"{0} does not exist！", path）;return;}// 读文件流FileStream fs = new FileStream（path, FileMode.Open,FileAccess.Read, FileShare.Read）;// 这部分需要完善string ContentType = "application/octet-stream";byte[] fileBytes = new byte[fs.Length];fs.Read（fileBytes, 0, Convert.ToInt32（fs.Length））;// 生成需要上传的二进制数组CreateBytes cb = new CreateBytes（）;// 所有表单数据ArrayList bytesArray = new ArrayList（）;// 普通表单bytesArray.Add（cb.CreateFieldData（"FileName", txtFilename.Text））;bytesArray.Add（cb.CreateFieldData（"AmigoToken", txtAmigoToken.Text））;// 文件表单bytesArray.Add（cb.CreateFieldData（"FileData", path, ContentType, fileBytes））;// 合成所有表单并生成二进制数组byte[] bytes = cb.JoinBytes（bytesArray）;// 返回的内容byte[] responseBytes;// 上传到指定Urlbool uploaded = cb.UploadData（"http://localhost/UploadData/UploadAvatar.aspx", bytes, out responseBytes）;// 将返回的内容输出到文件using （FileStream file = new FileStream（@"c: esponse.text", FileMode.Create, FileAccess.Write, FileShare.Read））{file.Write（responseBytes, 0, responseBytes.Length）;}txtResponse.Text = System.Text.Encoding.UTF8.GetString（responseBytes）;}private void btnBrowse_Click（object sender, System.EventArgs e）{if （openFileDialog1.ShowDialog（） == DialogResult.OK）{txtFileData.Text = openFileDialog1.FileName;}}}}