执行sql语句并使用流控制获取datareader

我的项目中有很多这样的东西,举个简单的例子:

enum QueryType {AQuery, BQuery};
private SqlDataReader DoQuery(QueryType _type)
{
    using (SqlConnection conn = new SqlConnection("your connection string"))
    {
        using (SqlCommand cmd = conn.CreateCommand())
        {
            switch(_type)
            {
                case QueryType.AQuery:
                    cmd.CommandText = @"SELECT thing FROM table";
                    break;
                case QueryType.BQuery:
                    cmd.CommandText = @"SELECT other_thing FROM table";
                    break;
            }
            conn.Open();
            SqlDataReader reader = cmd.ExecuteReader();
            //...
        }
    }
}

也许是这样的?

// delegate to use for adding parameters
delegate void AddParametersDelegate(IDbCommand cmd);

IDataReader GetReader(SomeEnumType val, AddParametersDelegate addParms)
{
    string sql = null;

    switch (val)
    {
        case EnumVal1:
            sql = "SQL Statement 1";
            break;
        case EnumVal2:
            sql = "SQL Statement 2";
            break;
        .
        default:
            sql = "Default SQL Statement";
            break;
    }

    using (IDbConnection conn = CreateDBConnection(connString))
    {
        using (IDbCommand cmd = conn.CreateCommand(sql))
        {
            // call the delegate to add the parameters to the SQL command
            addParams(cmd);

            return cmd.ExecuteReader(sql);
        }
    }
}