转换数据表到了IEnumerable＆LT; T＆GT; [英] Convert DataTable to IEnumerable<T>

问题描述

我想一个DataTable转换为一个IEnumerable。其中T是我创建了一个自定义类型。我知道我可以通过创建一个列表做，但我觉得有一个巧妙方式使用IEnumerable的做到这一点。以下是我现在有。

I am trying to convert a DataTable to an IEnumerable. Where T is a custom type I created. I know I can do it by creating a List but I was think there was a slicker way to do it using IEnumerable. Here is what I have now.

    private IEnumerable<TankReading> ConvertToTankReadings(DataTable dataTable)
    {
        var tankReadings = new List<TankReading>();
        foreach (DataRow row in dataTable.Rows)
        {
            var tankReading = new TankReading
                                  {
                                      TankReadingsID = Convert.ToInt32(row["TRReadingsID"]),
                                      TankID = Convert.ToInt32(row["TankID"]),
                                      ReadingDateTime = Convert.ToDateTime(row["ReadingDateTime"]),
                                      ReadingFeet = Convert.ToInt32(row["ReadingFeet"]),
                                      ReadingInches = Convert.ToInt32(row["ReadingInches"]),
                                      MaterialNumber = row["MaterialNumber"].ToString(),
                                      EnteredBy = row["EnteredBy"].ToString(),
                                      ReadingPounds = Convert.ToDecimal(row["ReadingPounds"]),
                                      MaterialID = Convert.ToInt32(row["MaterialID"]),
                                      Submitted = Convert.ToBoolean(row["Submitted"]),
                                  };
            tankReadings.Add(tankReading);
        }
        return tankReadings.AsEnumerable();
    }

关键部分是我创建一个列表，然后使用AsEnumerable（）返回它。

The key part being I am creating a List then returning it using AsEnumerable().

推荐答案

没有错的实现。你可以给收益关键字一拍，你看怎么样吧：

Nothing wrong with that implementation. You might give the yield keyword a shot, see how you like it:

private IEnumerable<TankReading> ConvertToTankReadings(DataTable dataTable)
    {
        foreach (DataRow row in dataTable.Rows)
        {
            yield return new TankReading
                                  {
                                      TankReadingsID = Convert.ToInt32(row["TRReadingsID"]),
                                      TankID = Convert.ToInt32(row["TankID"]),
                                      ReadingDateTime = Convert.ToDateTime(row["ReadingDateTime"]),
                                      ReadingFeet = Convert.ToInt32(row["ReadingFeet"]),
                                      ReadingInches = Convert.ToInt32(row["ReadingInches"]),
                                      MaterialNumber = row["MaterialNumber"].ToString(),
                                      EnteredBy = row["EnteredBy"].ToString(),
                                      ReadingPounds = Convert.ToDecimal(row["ReadingPounds"]),
                                      MaterialID = Convert.ToInt32(row["MaterialID"]),
                                      Submitted = Convert.ToBoolean(row["Submitted"]),
                                  };
        }

    }

另外， AsEnumerable 是没有必要的，因为列表＆LT; T＆GT; 已经是一个的IEnumerable＆LT; T＆GT;

Also the AsEnumerable isn't necessary, as List<T> is already an IEnumerable<T>

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