以网络形式在图像按钮上显示数据库中的图像

Question

我试图使图像从数据库中出现在Web窗体上的图像按钮上。没有错误消息，但图像未显示。只有一小的小，表明出现在图像按钮，但没有从数据库中的图像....

我的处理程序是在这里：

public void ProcessRequest (HttpContext context) 
{ 
     Int32 Member_No; 
     if (context.Request.QueryString["id"] != null) 
     { 
      Member_No = Convert.ToInt32(context.Request.QueryString["id"]); 
      context.Response.ContentType = "image/jpeg"; 

      Stream strm = ShowEmpImage(Member_No); 

      byte[] buffer = new byte[4096]; 
      int byteSeq = strm.Read(buffer, 0, 4096); 

      while (byteSeq > 0) 
      { 
       context.Response.OutputStream.Write(buffer, 0, byteSeq); 
       byteSeq = strm.Read(buffer, 0, 4096); 
      } 
     } 
     else 
     { 
      context.Response.Write("No Image Found"); 
     } 
    } 

    public bool IsReusable 
    { 
     get 
     { 
      return false; 
     } 
    } 

    public Stream ShowEmpImage(int Member_No) 
    { 
     SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["MyServer"].ConnectionString); 
     con.Open(); 
     SqlCommand cmd = new SqlCommand("Select Photo from Members where Member_No = @ID", con); 
     cmd.CommandType = CommandType.Text; 
     cmd.Parameters.AddWithValue("@ID", Member_No); 

     object img = cmd.ExecuteScalar(); 

     try 
     { 
      return new MemoryStream((byte[])img); 
     } 
     catch 
     { 
      return null; 
     } 
     finally 
     { 
      con.Close(); 
     } 
    } 
} 

Answer 1

我只想回到从执行标量byte[]和写入字节流。

public byte[] ShowEmpImage(int Member_No) 
{ 
    var settings = ConfigurationManager.ConnectionStrings["MyServer"]; 
    using(var con = new SqlConnection(settings.ConnectionString)) 
    using(var cmd = new SqlCommand("Select Photo from Members where Member_No = @ID", con)) 
    { 
     con.Open(); 
     cmd.CommandType = CommandType.Text; 
     cmd.Parameters.AddWithValue("@ID", Member_No); 

     return (byte[])cmd.ExecuteScalar(); 
    } 
} 

var image = ShowEmpImage(Member_No); 
context.Response.WriteBytes(image); 
context.Response.ContentType = "image/jpg"; 

BTW：我也想包你ado.net组件using块以防止内存泄漏。