ASP.NET MVC从MS SQL Server获取数据

Question

I am trying to get DataTable from my ms sql server. I added the connection string, tested connection, everything is ok. But each time i get empty result.

ProjectDbConnection.class

 public class ProjectDbConnection
    {
    protected SqlConnection SqlConnection;
            #region Open Connection

            public bool Open(string Connection = "WebProjectDB")
            {
                SqlConnection = new SqlConnection(@WebConfigurationManager.ConnectionStrings[Connection].ToString());
                try
                {
                    if (SqlConnection.State != ConnectionState.Open)
                    {
                        SqlConnection.Open();
                    }
                    return true;
                }
                catch (SqlException ex)
                {
                    return false;
                }
            }

            #endregion

            #region Close Connection

            public bool Close()
            {
                try
                {
                    SqlConnection.Close();
                    return true;
                }
                catch (Exception ex)
                {
                    return false;
                }
            }

            #endregion
      #region get table

            public DataTable GetTable(string sql)
            {
                var query = sql;
                var d = new DataTable();
                try
                {
                    if (SqlConnection.State == ConnectionState.Open)
                    {
                        var cmd = new SqlCommand(query, SqlConnection);
                        var reader = cmd.ExecuteReader();
                        d.Load(reader);
                        reader.Close();
                        return d;
                    }
                    return d;
                }
                catch (Exception ex)
                {
                    return d;
                }
            }

            #endregion
    }

Here i call the methods:

    ProjectDbConnection dbConnection = new ProjectDbConnection();
    dbConnection.Open();
    DataTable survey = dbConnection.GetTable("SELECT * FROM tbl_survey");
    DataTable criteriaClasification = dbConnection.GetTable("SELECT * FROM tbl_criteria_classification");
    DataTable criteriaElement = dbConnection.GetTable("SELECT * FROM tbl_criteria");
    dbConnection.Close();

Here is Web.config

 <connectionStrings>
    <add connectionString="Data Source=test-pc;Initial Catalog=WebProject;Integrated Security=True" name="WebProjectDB"/>
  </connectionStrings>

Answer 1

It look like SqlConnection is not open. Your connection string using windows authentication, but your network credential may not have access to database server.

Please change you connection to use SQL credential (passing sql username and password) and try to connect. Also change your code as stated below to make sure Gettable method will get called only if connection is open. If possible log the error if connection open failed.

ProjectDbConnection dbConnection = new ProjectDbConnection();
if (dbConnection.Open())
{
    DataTable survey = dbConnection.GetTable("SELECT * FROM tbl_survey");
    DataTable criteriaClasification = dbConnection.GetTable("SELECT * FROM tbl_criteria_classification");
    DataTable criteriaElement = dbConnection.GetTable("SELECT * FROM tbl_criteria");
    dbConnection.Close();
}