Question

我想从函数返回DataReader。所以我可以使用它，无论它是MySQL还是MS-SQL？

private void Connection(string Command)
{       
    if (DBtype == "MySQL")
    {
        MySqlConnection MysqlConnection1 = new MySqlConnection(CS);
        MySqlCommand MySqlcommand = new MySqlCommand(Command, MysqlConnection1);
        MysqlConnection1.Open();
        MySqlDataReader reader = MySqlcommand.ExecuteReader();
    }
    else
    {
        SqlConnection sqlConnection1 = new SqlConnection(CS);
        SqlCommand Sqlcommand = new SqlCommand(Command, sqlConnection1);
        sqlConnection1.Open();
        SqlDataReader reader = Sqlcommand.ExecuteReader();
    }  
}

Answer 1

您可以将方法的返回类型设为IDataReader，因为SqlDataReader和MySqlDataReader都会实现此接口。

private IDataReader Connection(string Command)
{
    IDataReader dataReader = null;

    if (DBtype == "MySQL")
    {
        MySqlConnection MysqlConnection1 = new MySqlConnection(CS);
        MySqlCommand MySqlcommand = new MySqlCommand(Command, MysqlConnection1);
        MysqlConnection1.Open();
        dataReader = MySqlcommand.ExecuteReader();
    }
    else
    {
        SqlConnection sqlConnection1 = new SqlConnection(CS);
        SqlCommand Sqlcommand = new SqlCommand(Command, sqlConnection1);
        sqlConnection1.Open();
        dataReader = Sqlcommand.ExecuteReader();
    }  

    return dataReader;
}

此外，我认为您应该将Connection方法作为参数传递给数据库的类型。

返回班级或者它是什么

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