using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;

/// <summary>
/// Summary description for UploadFile
/// </summary>
public class UploadFile
{
    private string[] AllowFileType; //所允许的文件类型
    private double FileLength; //所允许的文件大小(KB)
    private string SavePath; //文件的存储路径
    private string SaveFile; //上传后的文件名
    private string Error; //存储错误信息
    private string FileExtesion; //上传文件的扩展名

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="allFileType">允许的文件类型，多个以","分开</param>
    /// <param name="fileLength">文件大小</param>
    /// <param name="savePath">保存路径</param>
    public UploadFile(string allFileType, double fileLength, string savePath)
    {
        char[] sp = { ',' };
        AllowFileType = allFileType.Split(sp);
        FileLength = fileLength * 1024;
        SavePath = savePath;
    }

    /// <summary>
    /// 返回生成的文件名
    /// </summary>
    public string FileName
    {
        get
        {
            return SaveFile;
        }
    }

    /// <summary>
    /// 返回出错信息
    /// </summary>
    public string ErrorMessage
    {
        get
        {
            return Error;
        }
    }

    /// <summary>
    /// 根据SavePath,生成文件名
    /// </summary>
    /// <returns></returns>
    private string MakeFileName(string fileType,string fileName)
    {
        string file = this.SavePath + "\\" + DateTime.Now.ToString("yyMMddhhmmss") + fileName;
        while (File.Exists(file))
        {
            file = this.SavePath + "\\" + DateTime.Now.ToString("yyMMddhhmmss") + fileName;
        }
        return file;
    }

    /// <summary>
    /// 检查文件类型
    /// </summary>
    /// <param name="fileEx">MIME内容</param>
    /// <returns></returns>
    private bool CheckFileExt(string fileEx)
    {
        bool result = false;
        for (int i = 0; i < this.AllowFileType.Length; i++)
        {
            if (fileEx.IndexOf(this.AllowFileType[i].ToLower()) > -1)
            {
                result = true;
                break;
            }
        }
        return result;
    }

    public bool UpLoad(System.Web.UI.WebControls.FileUpload file)
    {
        bool result = true;
        try
        {
            //查看文件长度
            if (file.PostedFile.ContentLength > (this.FileLength))
            {
                this.Error = "文件大小超出范允许的范围！";
                return false;
            }

            string fileName = Path.GetFileName(file.PostedFile.FileName);
            this.FileExtesion = Path.GetExtension(fileName);

            if (!CheckFileExt(this.FileExtesion.ToLower()))
            {
                this.Error = "文件类型" + this.FileExtesion + "不允许！";
                return false;
            }
            //取得要保存的文件名
            string UpFile = this.MakeFileName(this.FileExtesion, fileName);
            //保存文件
            file.PostedFile.SaveAs(UpFile);

            //返回文件名
            this.SaveFile = Path.GetFileName(UpFile);

        }
        catch (Exception e)
        {
            result = false;
            this.Error = e.Message;
        }
        return result;
    }
}