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2.5.5 自定义的请求参数对象
现在，上传文件过程已经被我们接管了，上传的文件将被保存在我们指定的位置。在下面的实现中，通过System.IO.Path的静态方法GetTempFileName在系统的临时文件目录中创建一个文件，在上传过程中上传的文件将被保存在这里。为了能够访问这个文件的信息，必须自定义表示上传文件的类型。
为了表示自定义的请求参数，下面创建了FileItem用于表示一个上传文件对象。实现过程见代码清单2-3。
代码清单2-3 自定义的请求参数类型
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace DiskFileUpload
{
public class FileItem:System.IDisposable
{
public System.IO.Stream Stream { get; private set; }
public string ContentType { get; private set; }
public string Name { get; private set; }
public string Value{ get; set;}
public bool IsFormField { get; private set; }
public string ClientFullPath { get; private set; }
public string TempFullPath { get; private set; }
//构造函数
public FileItem(string name, bool isForm, string path, string contentType)
{
this.Name = name;
this.IsFormField = isForm;
this.ClientFullPath = path;
this.ContentType = contentType;
if (!this.IsFormField)
{
//创建临时文件
this.TempFullPath = System.IO.Path.GetTempFileName();
this.Stream = new System.IO.FileStream(
this.TempFullPath,
System.IO.FileMode.Create
);
}
}
public string FileName
{
get
{
return System.IO.Path.GetFileName(this.ClientFullPath);
}
}
public long Length
{
get
{
System.IO.FileInfo fi = new System.IO.FileInfo(this.TempFullPath);
return fi.Length;
}
}
//另存为
public void SaveAs(string path)
{
System.IO.File.Copy(
this.TempFullPath,
path
);
}
//删除临时文件
public void Delete()
{
if (System.IO.File.Exists(this.TempFullPath))
{
System.IO.File.Delete(this.TempFullPath);
}
}
public string ToContentString(string boundary)
{
System.Text.StringBuilder builder = new StringBuilder();
builder.AppendFormat("\r\nContent-Disposition:form-data;
name=\"{0}\"", this.Name);
if (this.IsFormField)
{
builder.Append("\r\n\r\n");
builder.AppendFormat("{0}",this.Value);
}
else
{
builder.AppendFormat("; filename=\"{0}\"\r\n",
this.ClientFullPath);
builder.Append("Content-Type:application/octet-stream\r\n");
builder.Append("\r\n");
}
builder.Append(boundary);
return builder.ToString();
}
public void Finish()
{
if(this.Stream != null)
this.Stream.Close();
}
#region IDisposable Members
public void Dispose()
{
if (this.Stream != null)
{
this.Stream.Dispose();
}
this.Delete();
}
#endregion
}
}
在一个表单中也可能同时上传多个文件，多个参数通过UploadFiles表示，见代码清单2-4。
代码清单2-4 多个参数的表示类型
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
namespace DiskFileUpload
{
public class UploadFiles :System.Collections.CollectionBase,
System.IDisposable
{
public static readonly string DiskFileUpload_GUID = "DiskFileUpload_GUID";
private NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();
public string ApplicationKey{ get; set; }
private int completePercent = 0;
public int CompletePercent
{
get { return this.completePercent; }
}
public void CompletePercentHander(object sender,
HttpWorkerFileUploadEventArgs e)
{
this.completePercent = (int)(e.Position * 100 /e.Length);
this.logger.Trace("Percent:{0}",
this.completePercent
);
}
public int Add(FileItem item)
{
return this.List.Add(item);
}
public void Insert(int index, FileItem value)
{
List.Insert(index, value);
}
public void Remove(FileItem value)
{
List.Remove(value);
}
public FileItem this[int index]
{
get
{
return ((FileItem)List[index]);
}
set
{
List[index] = value;
}
}
public string ToContentString(string boundary)
{
boundary = "\r\n--"+ boundary;
System.Text.StringBuilder builder = new StringBuilder();
builder.Append(boundary.Substring(2));
foreach (FileItem item in this.List)
{
builder.Append(item.ToContentString(boundary));
}
builder.Append("--\r\n");
return builder.ToString();
}
#region IDisposable Members
public void Dispose()
{
foreach (FileItem item in this)
{
item.Dispose();
}
HttpContext context = HttpContext.Current;
if (context != null)
{
HttpApplicationState application = context.Application;
application.Remove(UploadFiles.DiskFileUpload_GUID);
}
}
#endregion
}
}