C# 文件下载的一个问题

Question

比如我有个下载地址 http://www.ccc.com/11.rmvb 现在我是 <a href='http://www.ccc.com/11.rmvb'>文件下载</a>
现在就是点击文件下载就下载了但是我想把 在这个链接里加个后台判断用户是否登陆 登陆后才给他下载 没登陆就不给他下载如何如何做得到？

Answer 1

        <%if (Session["Name"] == null || Session["Name"].ToString() == "")
          {  %>
<a href='http://www.ccc.com/11.rmvb'>文件下载</a>
<% }
          else
          {%>
登录后才能下载
<% } %>

Answer 2

http://www.ccc.com/check.aspx?id=11.rmvb 这样请求发到一个后台上。Page_Load进行Check

Answer 3

http://www.csdn.com/down.aspx?id=11;                    FileInfo file = new FileInfo(Server.MapPath(path));
                    Response.Clear();
                    Response.AddHeader("content-disposition", "attachment;filename=" + HttpUtility.UrlEncode((file.Name), System.Text.Encoding.UTF8));
                    Response.AddHeader("content-length", file.Length.ToString());
                    Response.WriteFile(file.FullName);
                    Response.ContentType = "appliction/octet-stream";
                    Response.Flush();
                    Response.Close();
                    Response.End();

Answer 4

down.aspx
if(request.cookie["admin"]==null){
   //登陆
}
else{
                    FileInfo file = new FileInfo(Server.MapPath(path));
                    Response.Clear();
                    Response.AddHeader("content-disposition", "attachment;filename=" + HttpUtility.UrlEncode((file.Name), System.Text.Encoding.UTF8));
                    Response.AddHeader("content-length", file.Length.ToString());
                    Response.WriteFile(file.FullName);
                    Response.ContentType = "appliction/octet-stream";
                    Response.Flush();
                    Response.Close();
                    Response.End();
}

Answer 5

<%if (Session["Name"] !=null && !string.IsNullOrEmpty(Session["Name"].ToString()) == "")
  { %>
<a href='http://www.ccc.com/11.rmvb'>文件下载</a>
<% }%>
或 <%=str%>
或href='download.aspx?id=1 '根据ID判断是否有下载权限