文件上传通用类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using System.IO;
using System.Web.UI.WebControls;

public class FileUploadHelper
{
    private HttpPostedFile postedFile;

    public FileUploadHelper(HttpPostedFile postedFile)
    {
        this.postedFile = postedFile;
    }

    public void SaveAsById(string directoryRelativePath, string id)
    {
        string fullPath = string.Format("{0}/{1}{2}",
           directoryRelativePath,
            id,
            new FileInfo(postedFile.FileName).Extension);
        SaveAs(fullPath);
    }


    public void SaveAsByName(string directoryRelativePath, string fileName)
    {
        string fileSavePath = string.Format("{0}/{1}", directoryRelativePath, fileName);
        SaveAs(fileSavePath);
    }


    public void SaveAs(string fileRelativePath)
    {
        if (HasFile())
        {
            FileInfo fileInfo = new FileInfo(fileRelativePath);
            if (!Directory.Exists(fileInfo.Directory.FullName))
                Directory.CreateDirectory(fileInfo.Directory.FullName);
            postedFile.SaveAs(fileInfo.FullName);
        }
    }

    public string GetFileExtension()
    {
        if (HasFile())
            return new FileInfo(postedFile.FileName)
                .Extension;
        else
            return "";
    }

    public string GeName()
    {
        if (HasFile())
            return new FileInfo(postedFile.FileName)
                .Name;
        else
            return "";
    }

    public string GetSavePath(string directoryRelativePath, string id)
    {
        string fileName = string.Format("{0}{1}", id, new FileInfo(postedFile.FileName).Extension);
        return string.Format("{0}\\{1}", directoryRelativePath, fileName);
    }


    public bool HasFile()
    {
        return postedFile.ContentLength > 0;
    }
}