怎么把字段中存的二进制流读出

Question

图片是以二进制流存入表my_img 的字段img中的
现在要把图片显示出来，得怎么做?

Answer 1

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 readimage : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
         
          string connStr = ConfigurationManager.ConnectionStrings["DormConnectionString"].ConnectionString;
          SqlConnection dbconn = new SqlConnection(connStr);        
                 string strSql="select img from  test where id=205  ";
                 SqlCommand cmd = new SqlCommand();
                 cmd.Connection = dbconn;                 cmd.CommandType = CommandType.Text;
                  cmd.CommandText = strSql;
                 
                 SqlDataReader reader = cmd.ExecuteReader();
                 reader.Read();
                 Response.ContentType="application/octet-stream";
                 Response.BinaryWrite((Byte[])reader["img"]);
                 Response.End();
                 reader.Close();
          }
}
这样写那出错了?

Answer 2

异常详细信息: System.InvalidOperationException: ExecuteReader 要求已打开且可用的连接。连接的当前状态为已关闭。

Answer 3

Response.ContentType="application/octet-stream"; 
 Response.BinaryWrite((Byte[])reader["img"]); 
这两句代码就可以了!

Answer 4

SqlConnection Con = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]);
        String SqlCmd = "SELECT * FROM ImageStore WHERE ID = @ImageID";
        SqlCommand CmdObj = new SqlCommand(SqlCmd, Con);
        CmdObj.Parameters.Add("@ImageID", SqlDbType.Int).Value = "";
        Con.Open();
        SqlDataReader SqlReader = CmdObj.ExecuteReader();
        SqlReader.Read();
        Response.ContentType = (string)SqlReader["ImageContentType"];//设定输出文件类型       
         Response.OutputStream.Write((byte[])SqlReader["ImageData"],0,Convert.ToInt32(SqlReader["ImageSize"]));
        Response.BufferOutput = true;
        Con.Close();