C# 抽象方法

Question

我有一组方法，接受日期和 bool 值。然后，这些方法使用一些 SQL，然后将其传递给另一个方法并返回一个列表。除了 SQL 和返回的列表之外，每个方法都几乎相同。现在我知道有更好的方法来执行这些方法，但我不确定如何执行。

由于方法几乎相同，有人对我如何抽象它或使用更好的设计有任何想法吗？

这是代码:

private List<ENT_Message> GetMessageData(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_Message> ret = new List<ENT_Message>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_message";
    }
    else
    {
        sql = " Select * from tbl_message where created_Date between @start_Date and @end_date";
    }

    return Converter.SerializeToMessageList(this.GetData(startDate, endDate, IsSelectAll, sql));                   
}

private List<ENT_SensorData> GetSensorData(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_SensorData> ret = new List<ENT_SensorData>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_sensor_data";
    }
    else
    {
        sql = "select * from tbl_sensor_data where Timestamp between @start_date and @end_Date";
    }

    return Converter.SerializeToSensorDataList(this.GetData(startDate, endDate, IsSelectAll, sql)); 
}

private List<ENT_SensorDataEvent> GetSensorDataEvents(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_SensorDataEvent> ret = new List<ENT_SensorDataEvent>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_sensor_data_event";
    }
    else
    {
        sql = "select * from tbl_sensor_data_event where start_time between @start_date and @end_Date";
    }

    return Converter.SerializeToSensorEventDataList(this.GetData(startDate, endDate, IsSelectAll, sql)); 
}

private List<ENT_SensorDataState> GetSensorDataState(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_SensorDataState> ret = new List<ENT_SensorDataState>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_sensor_data_state";
    }
    else
    {
        sql = "select * from tbl_sensor_data_state where start_time between @start_date and @end_Date";
    }

    return Converter.SerializeToSensorDateStateList(this.GetData(startDate, endDate, IsSelectAll, sql)); 
}

private List<ENT_WorkOrder> GetWorkOrders(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_WorkOrder> ret = new List<ENT_WorkOrder>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_workorder";
    }
    else
    {
        sql = "select * from tbl_sensor_data_state where completed_date between @start_date and @end_Date";
    }

    return Converter.SerializeToWorkOrderList(this.GetData(startDate, endDate, IsSelectAll, sql));   
}

Answer 1

您可以大大缩短您的函数。例如，代替

private List<ENT_SensorDataState> GetSensorDataState(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    List<ENT_SensorDataState> ret = new List<ENT_SensorDataState>();
    string sql = "";

    if (IsSelectAll)
    {
        sql = "select * from tbl_sensor_data_state";
    }
    else
    {
        sql = "select * from tbl_sensor_data_state where start_time between @start_date and @end_Date";
    }

    return Converter.SerializeToSensorDateStateList(this.GetData(startDate, endDate, IsSelectAll, sql));
}

你可以简单地写

private List<ENT_SensorDataState> GetSensorDataState(DateTime? startDate, DateTime? endDate, bool IsSelectAll)
{
    string sql = "select * from tbl_sensor_data_state"
                 + (IsSelectAll ? "" : "where start_time between @start_date and @end_Date");

    return Converter.SerializeToSensorDateStateList(this.GetData(startDate, endDate, IsSelectAll, sql));
}

这基本上将您的函数简化为真正重要的内容:SQL 和序列化函数的名称。