用 WebClient.UploadData 方法 上载文件数据

假如某网站有个表单，例如(url: http://localhost/login.aspx)：
帐号 密码
我们需要在程序中提交数据到这个表单，对于这种表单，我们可以使用 WebClient.UploadData 方法来实现，将所要上传的数据拼成字符即可，程序很简单：

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ContentTypemyWebClient.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);

对于文件上传类的表单，例如(url: http://localhost/uploadFile.aspx)：
文件
对于这种表单，我们可以使用

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);

还有一种表单，不仅有文字，还有文件，例如(url: http://localhost/uploadData.aspx)：
文件名 文件
对于这种表单，似乎前面的两种方法都不能适用，对于第一种方法，不能直接拼字符串，对于第二种，我们只能传文件，重新回到第一个方法，注意参数：
public byte[] UploadData(
   string address,
   string method,
   byte[] data
);
在第一个例子中，是通过拼字符串来得到byte[] data参数值的，对于这种表单显然不行，反过来想想，对于uploadData.aspx这样的程序来说，直接通过网页提交数据，后台所获取到的流是什么样的呢？（在我以前的一篇blog中，曾分析过这个问题：asp无组件上传进度条解决方案），最终的数据如下：

-----------------------------7d429871607feContent-Disposition: form-data; name="file1"; filename="G:/homepage.txt"Content-Type: text/plain宝玉：http://www.webuc.net-----------------------------7d429871607feContent-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。

具体代码如下：
生成二进制数据类的封装

using System;using System.Web;using System.IO;using System.Net;using System.Text;using System.Collections;namespace UploadData.Common...{    /**//// <summary>    /// 创建WebClient.UploadData方法所需二进制数组    /// </summary>    public class CreateBytes    ...{        Encoding encoding = Encoding.UTF8;        /**//// <summary>        /// 拼接所有的二进制数组为一个数组        /// </summary>        /// <param name="byteArrays">数组</param>        /// <returns></returns>        /// <remarks>加上结束边界</remarks>        public byte[] JoinBytes(ArrayList byteArrays)        ...{            int length = 0;            int readLength = 0;            // 加上结束边界            string endBoundary = Boundary + "--/r/n"; //结束边界            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;         }        /**//// <summary>        /// 获取普通表单区域二进制数组        /// </summary>        /// <param name="fieldName">表单名</param>        /// <param name="fieldValue">表单值</param>        /// <returns></returns>        /// <remarks>        /// -----------------------------7d52ee27210a3c/r/nContent-Disposition: form-data; name=/"表单名/"/r/n/r/n表单值/r/n        /// </remarks>        public byte[] CreateFieldData(string fieldName, string fieldValue)        ...{            string textTemplate = Boundary + "/r/nContent-Disposition: form-data; name=/"{0}/"/r/n/r/n{1}/r/n";            string text = String.Format(textTemplate, fieldName, fieldValue);            byte[] bytes = encoding.GetBytes(text);            return bytes;        }                /**//// <summary>        /// 获取文件上传表单区域二进制数组        /// </summary>        /// <param name="fieldName">表单名</param>        /// <param name="filename">文件名</param>        /// <param name="contentType">文件类型</param>        /// <param name="contentLength">文件长度</param>        /// <param name="stream">文件流</param>        /// <returns>二进制数组</returns>        public byte[] CreateFieldData(string fieldName, string filename,string contentType, byte[] fileBytes)        ...{            string end = "/r/n";            string textTemplate = Boundary + "/r/nContent-Disposition: form-data; name=/"{0}/"; filename=/"{1}/"/r/nContent-Type: {2}/r/n/r/n";                        // 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); // /r/n            return fieldData;        }        属性#region 属性        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;            }        }        #endregion    }}

在Winform中调用

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...{    /**//// <summary>    /// frmUpload 的摘要说明。    /// </summary>    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;        /**//// <summary>        /// 必需的设计器变量。        /// </summary>        private System.ComponentModel.Container components = null;        public frmUpload()        ...{            //            // Windows 窗体设计器支持所必需的            //            InitializeComponent();            //            // TODO: 在 InitializeComponent 调用后添加任何构造函数代码            //        }        /**//// <summary>        /// 清理所有正在使用的资源。        /// </summary>        protected override void Dispose( bool disposing )        ...{            if( disposing )            ...{                if (components != null)                 ...{                    components.Dispose();                }            }            base.Dispose( disposing );        }        Windows 窗体设计器生成的代码#region Windows 窗体设计器生成的代码        /**//// <summary>        /// 设计器支持所需的方法 - 不要使用代码编辑器修改        /// 此方法的内容。        /// </summary>        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);        }        #endregion        /**//// <summary>        /// 应用程序的主入口点。        /// </summary>        [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Url            bool 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:/response.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;            }        }    }}

完整的代码见附件: UploadData.rar(38K)，解压后给web目录建个虚拟目录"UploadData"，其中UploadAvatar.aspx是实际的上传处理页，如果上传成功，则返回文件名和文件类型等信息。default.aspx是asp.net页面来调用 WebClient.UploadData方法提交数据，UploadDataWin项目则是winform程序调用。