EF MVC的LINQ - 错误传递模型到MVC的WebGrid

Question

当我试图通过LINQ查询的结果为MVC.Webgrid我收到错误（简体）：

The model item passed into the dictionary is of 
type'System.Data.Entity.Infrastructure.DbQuery but 
this dictionary requires a model item of type 
'System.Collections.Generic.IEnumerable`1[MyModel.Models.MyMetric]' 

这是的ActionResult失败：

public ActionResult Test() 
    { 
     var metrics = db.Metrics 
      .GroupBy(c => c.Year) 
      .Select(g => new 
      { 
       Year = g.Key, 
       Q1 = g.Where(c => c.Quarter == 1).Sum(c => c.Value), 
       Q2 = g.Where(c => c.Quarter == 2).Sum(c => c.Value), 
       Q3 = g.Where(c => c.Quarter == 3).Sum(c => c.Value), 
       Q4 = g.Where(c => c.Quarter == 4).Sum(c => c.Value) 
      });       
     return View(metrics); 
    } 

我假设，因为我创造，我需要建立某种形式的新模型对原始数据的支点，但我不确定该怎么做，在这种情况下。 （只是让我的脚湿透EF和MVC）

任何想法？

TIA Ĵ

Answer 1

你传递一个匿名类型的图，而你应该通过一个IEnumerable<MyMetric>。因此，假设MyMetric看起来是这样的：

public class MyMetric 
{ 
    public int Year { get; set; } 
    public int Q1 { get; set; } 
    public int Q2 { get; set; } 
    public int Q3 { get; set; } 
    public int Q4 { get; set; } 
} 

你只需从你的LINQ查询返回一个IEnumerable<MyMetric>：

public ActionResult Test() 
{ 
    var metrics = db.Metrics 
     .GroupBy(c => c.Year) 
     .Select(g => new MyMetric 
     { 
      Year = g.Key, 
      Q1 = g.Where(c => c.Quarter == 1).Sum(c => c.Value), 
      Q2 = g.Where(c => c.Quarter == 2).Sum(c => c.Value), 
      Q3 = g.Where(c => c.Quarter == 3).Sum(c => c.Value), 
      Q4 = g.Where(c => c.Quarter == 4).Sum(c => c.Value) 
     });       
    return View(metrics); 
}