我有以下類作為列表;class list_TA{ public DateTime SAMPLE_TIME { get; set; } public string WAIT_CLASS { get; set; } public double COUNT { get; set; } public list_TA(DateTime SAMPLE_TIME, string WAIT_CLASS,double COUNT) { this.SAMPLE_TIME = SAMPLE_TIME; this.WAIT_CLASS = WAIT_CLASS; this.COUNT = COUNT; }}//SECOND PART var test = listASH .Select(g => new { SAMPLE_TIME = statiClass.By15Seconds(Convert.ToDateTime(g.SAMPLE_TIME)), WAIT_CLASS = g.WAIT_CLASS, COUNT = 0, }).GroupBy(x => new { x.SAMPLE_TIME, x.WAIT_CLASS }) .Select(y => new { SAMPLE_TIME = y.Key.SAMPLE_TIME, WAIT_CLASS = y.Key.WAIT_CLASS, COUNT = Math.Round(y.Count() / 15.0, 2), });我想要的是將linq結果加載到list_TA中。但是下面的代碼不起作用，它給出了以下錯誤; List<list_TA> lst = (List<list_TA>)test.ToList(); 錯誤;Cannot convert type 'System.Collections.Generic.List<<anonymous type: System.DateTime SAMPLE_TIME, string WAIT_CLASS, double COUNT>>' to 'System.Collections.Generic.List<vodaMon.list_TA>'正在轉換為列表（）;不起作用。
3 回答
Helenr
TA貢獻1780條經驗 獲得超4個贊
也使用代替任意值類型：當您實例化list_TA時，它需要DateTime SAMPLE_TIME，字符串WAIT_CLASS，雙倍計數作為參數傳遞。為了解決這個問題，請引入無參數構造函數。new list_TA
public class list_TA
{
public DateTime SAMPLE_TIME { get; set; }
public string WAIT_CLASS { get; set; }
public double COUNT { get; set; }
public list_TA()
{
}
public list_TA(DateTime SAMPLE_TIME, string WAIT_CLASS, double COUNT)
{
this.SAMPLE_TIME = SAMPLE_TIME;
this.WAIT_CLASS = WAIT_CLASS;
this.COUNT = COUNT;
}
}
慕仙森
TA貢獻1827條經驗 獲得超8個贊
您可以在 LINQ 中選擇list_TA，如下所示：
var test = listASH
.Select(g => new
{
SAMPLE_TIME = statiClass.By15Seconds(Convert.ToDateTime(g.SAMPLE_TIME)),
WAIT_CLASS = g.WAIT_CLASS,
COUNT = 0,
}).GroupBy(x => new { x.SAMPLE_TIME, x.WAIT_CLASS })
.Select(y => new list_TA
{
SAMPLE_TIME = y.Key.SAMPLE_TIME,
WAIT_CLASS = y.Key.WAIT_CLASS,
COUNT = Math.Round(y.Count() / 15.0, 2),
}).ToList();
慕斯709654
TA貢獻1840條經驗 獲得超5個贊
匿名類不能隱式轉換為任何其他類型。
您需要使用而不是new list_TAnew
將默認構造函數添加到類中，并使用以下代碼list_TA
.Select(y => new list_TA
{
SAMPLE_TIME = y.Key.SAMPLE_TIME,
WAIT_CLASS = y.Key.WAIT_CLASS,
COUNT = Math.Round(y.Count() / 15.0, 2),
});
或
.Select(y => new list_TA (
y.Key.SAMPLE_TIME,
y.Key.WAIT_CLASS,
Math.Round(y.Count() / 15.0, 2)
));
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