C# 使用LINQ为每个属性连接2个对象

我创建了两个模型来存储sql查询的结果。现在我想和他们一起参加每周的<代码>（第一周=记录id，第二周=记录id） 为了得到一个新的对象，我将拥有第一个模型中的所有数据，以及“类别”模型中的映射数据

我为它创建了一个新模型，但我不确定如何编写linq查询

第一款：

public class CustomData
{
    public string full_name { get; set; }
    public string location { get; set; }
    public int week1 { get; set; }
    public int week2 { get; set; }
    public int week3 { get; set; }
}

第二种模式：

public class Category
{
    public int Record_ID { get; set; }
    public int Color{ get; set; }
    public string Name { get; set; }
}

最终结果的新模型：

public class WeekView
{
    public string full_name { get; set; }
    public string location { get; set; }
    public Category week1 { get; set; }
    public Category week2 { get; set; }
    public Category week3 { get; set; }
}

这应该起作用：

        List<CustomData> list = new List<CustomData>();
        list.Add(new CustomData() { full_name = "test", location = "test", week1 = 0, week2 = 1, week3 = 2 });
        list.Add(new CustomData() { full_name = "test2", location = "test2", week1 = 0, week2 = 12, week3 = 22 });
        List<Category> categories = new List<Category>();
        categories.Add(new Category { Color = 0, Name = "testName", Record_ID = 0 });
        categories.Add(new Category { Color = 1, Name = "testName1", Record_ID = 1 });
        categories.Add(new Category { Color = 2, Name = "testName2", Record_ID = 2 });
        categories.Add(new Category { Color = 3, Name = "testName3", Record_ID = 12 });
        categories.Add(new Category { Color = 4, Name = "testName4", Record_ID = 22 });
        List<WeekView> results = new List<WeekView>();
        results.AddRange(list.Select(x=> 
              new WeekView() { full_name = x.full_name, 
                               location = x.location, 
                               week1 = categories.FirstOrDefault(c => c.Record_ID == x.week1), 
                               week2 = categories.FirstOrDefault(c => c.Record_ID == x.week2), 
                               week3 = categories.FirstOrDefault(c => c.Record_ID == x.week3)
                              }));

List List=新列表（）；
添加（新的CustomData（）{full_name=“test”，location=“test”，week1=0，week2=1，week3=2}）；
添加（新的CustomData（）{full_name=“test2”，location=“test2”，week1=0，week2=12，week3=22}）；
列表类别=新列表（）；
添加（新类别{Color=0，Name=“testName”，Record_ID=0}）；
添加（新类别{Color=1，Name=“testName1”，Record_ID=1}）；
添加（新类别{Color=2，Name=“testName2”，Record_ID=2}）；
添加（新类别{Color=3，Name=“testName3”，Record_ID=12}）；
添加（新类别{Color=4，Name=“testName4”，Record_ID=22}）；
列表结果=新列表（）；
results.AddRange（list.Select）（x=>
新建WeekView（）{full_name=x.full_name，
位置=x.位置，
week1=categories.FirstOrDefault（c=>c.Record_ID==x.week1），
week2=categories.FirstOrDefault（c=>c.Record\u ID==x.week2），
week3=categories.FirstOrDefault（c=>c.Record\u ID==x.week3）
}));

尝试以下操作：

var result = (from cd in CustomDatas
              join ca1 in Categories on cd.week1 equals ca.Record_ID into ca1r
              from ca1 in ca1r.DefaultIfEmpty()
              join ca2 in Categories on cd.week2 equals ca.Record_ID into ca2r
              from ca2 in ca2r.DefaultIfEmpty()
              join ca3 in Categories on cd.week3 equals ca.Record_ID into ca3r
              from ca3 in ca3r.DefaultIfEmpty()
              select new {
                    full_name = cd.full_name,
                    location = cd.location,
                    week1 = ca1,
                    week2 = ca2,
                    week3 = ca3
              }

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示例数据请在类别中加入ca1-类别是一种类型，在给定上下文中无效。类别在哪里是一种类型？类型为类别。在本例中，我假设有一个列表（或任何其他可枚举对象）和一组Category对象。您也可以执行

categories.FirstOrDefault（c=>c.Record\u ID==x.week1）

它将是相同的，但更简洁。