日期:2014-05-17  浏览次数:20412 次

asp.net 实现从数据库下载文件
问题:我把txt、doc等文件以二进制的形式存储到数据库,但是我在从数据库里下载后的文件却无法打开……
下载的方法在网上找到,如下:
context.Response.AddHeader("Content-Disposition","attachment;filename=" + HttpUtility.UrlEncode(dr["CTitle"].ToString()));
context.Response.BinaryWrite((Byte[])dr["CContent"]);
本人小白一个,高手看不惯的勿喷!
求解惑——为什么无法打开?
或者请给我一个类似的例子让我自己琢磨,谢谢!

------解决方案--------------------
完整的例子
HTML code
<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  protected void Button1_Click(object sender, EventArgs e)
  {
    //得到文件数组
    byte[] fileData = FileUpload1.FileBytes;
    //得到文件大小
    int fileLength = FileUpload1.PostedFile.ContentLength;
    //得到文件名字
    string fileName = System.IO.Path.GetFileName( FileUpload1.FileName);

    //得到文件类型
    string fileType = FileUpload1.PostedFile.ContentType;

    //构建数据库连接,SQL语句,创建参数
    string strCnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|Image2Access.mdb";
    System.Data.OleDb.OleDbConnection myConnection = new System.Data.OleDb.OleDbConnection(strCnString);
    String strSql = "INSERT INTO FileTable (ContentType,Content,Title)" +
                    "VALUES (@ContentType,@Content,@Title)";
    System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(strSql, myConnection);
    command.Parameters.AddWithValue("@ContentType", fileType);   
    command.Parameters.AddWithValue("@Content", fileData);
    command.Parameters.AddWithValue("@Title", fileName);  
    //打开连接,执行查询
    myConnection.Open();
    command.ExecuteNonQuery();
    myConnection.Close();
    Response.Redirect(Request.FilePath);
  }

  protected void Page_Load(object sender, EventArgs e)
  {
   
    //构建数据库连接,SQL语句,创建参数
    string strCnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|Image2Access.mdb";
    System.Data.OleDb.OleDbConnection myConnection = new System.Data.OleDb.OleDbConnection(strCnString);
    String strSql = "select * from FileTable";
    System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(strSql, myConnection);
    //打开连接,执行查询
    myConnection.Open();
    System.Data.OleDb.OleDbDataReader dr = command.ExecuteReader();
    GridView1.DataSource = dr;
    GridView1.DataBind();    
    myConnection.Close();
  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
  <title></title>
</head>
<body>
  <form id="form1" runat="server">
  <asp:FileUpload ID="FileUpload1" runat="server" />
  <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="上传文件" />
  <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
  <Columns>
  <asp:HyperLinkField DataNavigateUrlFields="FileId" DataTextField="Title" DataNavigateUrlFormatString="~/Download.aspx?FileId={0}"/>  
  </Columns>
  </asp:GridView>
  </form>
</body>
</html>

------解决方案--------------------
参考:
http://www.cnblogs.com/insus/articles/1411761.html
http://www.cnblogs.com/insus/articles/2003336.html
------解决方案--------------------
只能给你一点建议的,我的程序是用DELPHI+MSSQL2005编写的
数据库中的表是
字段名 FILENAME FILEDDD
类型 nvarchar(30) image
将文件内容以内存流方式写入FILEDDD中,读取时再以内存流方式读取并保存文件
名为FILENAME即可,再用外部的程序打开即可