C＃加入3列出了使用LINQ

我想加入3列出了具有以下格式：C＃加入3列出了使用LINQ

List1: 
    CountryID | CountryData  | regionUID 
    =================================== 
     12 | Has good gras | 4567 
     12 | nice weather | 6789 
     16 | stormy weather | 1234 

List2: 
    CountryID | CountryName 
    ======================= 
     12 | green hill 
     16 | stormy mountain 

List3: 
    regionUID | regionName 
    ======================= 
     4567 | above 1000feet 
     6789 | on the ground 
     1234 | on the hill

輸出應該是這樣的：

CountryName  | CountryData  | regionName 
============================================== 
green hill  | Has good gras | above 1000feet 
green hill  | nice weather  | on the ground 
stormy mountain | stormy weather | on the hill

，其中區域是獨一無二的，國家能適合多線

來源

2013-05-21 user2367984

如果您只是對LINQ Join的語法感興趣，請參閱http://stackoverflow.com/questions/37324/what-is-the-syntax-for-an-inner-join-in -linq-to-sql –

只需在Google中鍵入'將鏈接列表與Linq c＃'鍵入，就可以返回無數的好答案，因爲沒有研究工作。 –

你想是這樣的：

var list1 = new []{ 
    new { CountryID = 12, CountryData = "Has good gras", regionUID = 4567 }, 
    new { CountryID = 12, CountryData = "nice weather", regionUID = 6789 }, 
    new { CountryID = 16, CountryData = "stormy weather", regionUID = 1234 }}; 

var list2 = new []{ 
    new { CountryID = 12, CountryName = "green hill"}, 
    new { CountryID = 16, CountryName = "stormy mountain"} 
}; 

var list3 = new []{ 
    new {regionUID = 4567, regionName = "above 1000feet"}, 
    new {regionUID = 6789, regionName = "on the ground"}, 
    new {regionUID = 1234, regionName = "on the hill"} 
}; 

var result = from m1 in list1 
    join m2 in list2 on m1.CountryID equals m2.CountryID 
    select new { m2.CountryName, m1.CountryData, m1.regionUID } into intermediate 
    join m3 in list3 on intermediate.regionUID equals m3.regionUID 
    select new { intermediate.CountryName, intermediate.CountryData, m3.regionName};

來源

2013-05-21 20:44:20 musicologyman

C＃加入3列出了使用LINQ

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