找不到类型或命名空间名称“FileStream”(是否缺少 using 指令或程序集引用?)

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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.Data.SqlClient;

public partial class up : System.Web.UI.Page
{
    //SqlConnection con = new SqlConnection("server=.;database=photoDB;integrated security=sspi");



    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
      string name = FileUpload1.PostedFile.FileName;
      string type = name.Substring(name.LastIndexOf(".") + 1);
      FileStream fs = File.OpenRead(name);
      byte[] content = new byte[fs.Length];
      fs.Read(content, 0, content.Length);
      fs.Close();

      SqlConnection conn = new SqlConnection("server=.;database=photoDB;integrated security=sspi");
      SqlCommand cmd = conn.CreateCommand();
      conn.Open();
      cmd.CommandText = "insert into upphoto (Image_Content) values (@content)";
      cmd.CommandType = CommandType.Text;

      if (type == "jpg" || type == "gif" ||   type == "bmp" || type == "png")
     {
       SqlParameter para = cmd.Parameters.Add ("@content", SqlDbType.Image);
       para.Value = content;
       cmd.ExecuteNonQuery();
     }
    }
}
错误 1 找不到类型或命名空间名称“FileStream”(是否缺少 using 指令或程序集引用?) E:\photo111\photo1111\up.aspx.cs 30 7 E:\photo111\photo1111\
--------------------编程问答-------------------- 这是段上传代码     找不到类型或命名空间名称“FileStream”(是否缺少 using 指令或程序集引用?)

具体该怎么解决呢 --------------------编程问答-------------------- 添加IO引用即可，如下红色部分。

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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.Data.SqlClient;

using System.IO; --------------------编程问答-------------------- using System.IO; --------------------编程问答--------------------

以后遇到这种情况自己搞。 --------------------编程问答-------------------- 嗯嗯谢谢另外这段代码好像上传功能没有实现啊怎么办上传之后数据库里没有显示我用的是SQL2005

补充：.NET技术 ,  ASP.NET