MultipleActiveResultSets已啓用但無法正常工作

Question

我啓用了MARS，但仍然無法在一個連接中執行兩個SqlDataReaders，我搜索了一個解決方案，默認情況下使用RegEdit啓用MARS，但找不到任何解決方案，並且仍然出現該錯誤：已經有一個打開的DataReader與此命令關聯，必須先關閉該命令。

下面是代碼：

public partial class student_Courses : System.Web.UI.Page 
{ 
    string connectionString = ""; 
    string query1 = ""; 
    string query2 = ""; 
    string courseName = ""; 
    string chapterName = ""; 
    string chapterVideoName = ""; 
    string courseValue = ""; 
    SqlDataReader sr2 = null; 

    protected void Page_Load(object sender, EventArgs e) 
    { 
     query1 = "SELECT * FROM Courses"; 
     query2 = "SELECT * FROM Chapters WHERE value='" + courseValue + "'"; 
     connectionString = "Data Source=Prince-PC;" + 
          "Initial Catalog=Elearning;" + 
          "Integrated Security=True;"+ 
          "MultipleActiveResultSets=True"; 
     SqlConnection con = new SqlConnection(connectionString); 
     SqlCommand command1 = new SqlCommand(query1, con); 
     SqlCommand command2 = new SqlCommand(query2, con); 
     if (con.State == ConnectionState.Closed) 
      con.Open(); 

     using (SqlDataReader sr1 = command1.ExecuteReader()) 
     { 
      while (sr1.Read()) 
      { 
       courseName = sr1["name"].ToString(); 
       courseValue = sr1["value"].ToString(); 
       sr2 = command2.ExecuteReader(); 
       while (sr2.Read()) 
       { 
        chapterName = TextBox3.Text = sr2["name"].ToString(); 
        chapterVideoName = Label2.Text = sr2["video_name"].ToString(); 
       } 
      } 
     } 
     con.Close(); 
    } 
} 

Answer 1

你需要通過using陳述處置sr2爲this MSDN MARS example

// The following line of code requires 
// a MARS-enabled connection. 
productReader = productCmd.ExecuteReader(); 
using (productReader) 
{ 
    while (productReader.Read()) 
    { 
    Console.WriteLine(" " + 
     productReader["Name"].ToString()); 
    } 
} 

完成