執行閱讀器需要打開連接

Question

我收到此錯誤「執行閱讀器需要打開連接」。我用Google搜索了一切，並嘗試了一切。我似乎找不到錯誤的根源。它昨天在工作。

public bool ValidRegLogUser() 
     { 
      bool _UserValid = false; 

       try 
       { 
        string querystring = "Select * from users where UserName=@userName and userPassword=@userPassword"; 
        SqlCommand command = new SqlCommand(querystring,con); 
        command.Parameters.Add("@userName", SqlDbType.VarChar).Value =  UserName; 
        command.Parameters.Add("@userPassword", SqlDbType.VarChar).Value =  Password; 

        openConnection(); 

        using (SqlDataReader conReader = command.ExecuteReader()) 
        { 
         if (conReader.Read() == true) 
         { 
          UserName = Convert.ToString(conReader["userName"]); 
          LogType = Convert.ToString(conReader["userPrivileges"]); 
          _UserValid = true; 
         } 
        } 
       } 
       catch (Exception ex) 
       { 
       MessageBox.Show(ex.Message); 
       } 
       finally 
       { 
        //conReader.Close(); 
        closeConnection(); 
       } 
      return _UserValid; 

Answer 1

使用using語句，而不是關閉finally塊中的連接。 SqlConnection實現了IDisposable。創建連接並打開它就像這樣：

public bool ValidRegLogUser() 
     { 
      bool _UserValid = false; 

       using(var conn = new SqlConnection()) 
       { 
        string querystring = "Select * from users where UserName=@userName and userPassword=@userPassword"; 
        SqlCommand command = new SqlCommand(querystring,conn); 
        command.Parameters.Add("@userName", SqlDbType.VarChar).Value =  UserName; 
        command.Parameters.Add("@userPassword", SqlDbType.VarChar).Value =  Password; 

        conn.Open(); 

        using (SqlDataReader conReader = command.ExecuteReader()) 
        { 
         if (conReader.Read() == true) 
         { 
          UserName = Convert.ToString(conReader["userName"]); 
          LogType = Convert.ToString(conReader["userPrivileges"]); 
          _UserValid = true; 
         } 
        } 
       } 

      return _UserValid; 
     } 

無論你的神祕方法openConnection();你大概可以擺脫它。