我有一个linq查询返回未知类型值的列表。我想包括在此方法查询和使用方法返回未知类型列表的方法
public __________ getResult() {
var result = from ps in _context.PurchasingShipments
group ps by ps.date.Value.Year into grp
select new
{
Year = grp.Key,
Cost = grp.Sum(x => x.NoOfPieces * x.PricePerPiece + x.Micelleneous + x.TransportCost + x.SupplierCommission)
};
return result;
}
以上是一个例子，应该是什么的getResult方法的返回类型得到的结果？请帮助
解决方案1：我强烈建议您创建一个包含你的属性模型，并返回一个列表模型。
public class CostYearModel {
public int Year { get; set; }
public int Cost { get; set; }
}
的方法会像下面
public List<CostYearModel> getResult() {
var result = from ps in _context.PurchasingShipments
group ps by ps.date.Value.Year into grp
select new CostYearModel
{
Year = grp.Key,
Cost = grp.Sum(x => x.NoOfPieces * x.PricePerPiece + x.Micelleneous + x.TransportCost + x.SupplierCommission)
};
return result.ToList();
}
解决方案2：如果不能和/或不愿意为此创建模型，不好的解决方案将返回一个对象列表。您可以通过反射访问值。
public List<Object> getResult() {
var result = from ps in _context.PurchasingShipments
group ps by ps.date.Value.Year into grp
select (new
{
Year = grp.Key,
Cost = grp.Sum(x => x.NoOfPieces * x.PricePerPiece + x.Micelleneous + x.TransportCost + x.SupplierCommission)
} as Object);
return result.ToList();
}
访问每个属性的值（在您的案例中的成本和年份）的代码如下所示。
foreach (var costYear in result)
{
var properties = costYear.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (var property in properties)
{
var value = property.GetValue(costYear, null);
}
}
只能返回对象，你应该创建一个类：
public class CostYearModel{
public int Year {get; set;}
public int Cost {get; set;}
}
public List<CostYearModel> getResult() {
var result = from ps in _context.PurchasingShipments
group ps by ps.date.Value.Year into grp
select new CostYearModel
{
Year = grp.Key,
Cost = grp.Sum(x => x.NoOfPieces * x.PricePerPiece + x.Micelleneous + x.TransportCost + x.SupplierCommission)
};
return result.ToList();
}
您可能希望将'CustomClass'更改为'CostYearModel' – Alex 2015-04-04 05:37:39
您正在'select'语句中创建一个匿名类型，因此'result'将是匿名类型的枚举类型。唯一能够返回的方式是'IEnumerable