簡單的從泛型列表

Question

選擇我有一個列表：

List<Product> allProducts = new List<Product>();

產品可以有相同的顯示名稱，但不同的URL：秒。我想要做的是獲得每個產品的所有網址。

foreach (Product p in allProducts.Distinct().ToList()) 
    { 
     string displayname = p.GetDisplayName(); 
     string url = p.GetPublishedUrls()[0]; 
    } 

但我在這裏卡住了。任何幫助表示讚賞！

Answer 1

使用的GroupBy：

foreach (var productGroup in allProducts.GroupBy(p => p.GetDisplayName()) { 
    # productGroup.Key is the display name 
    # and productGroup enumerates all the products for the display name 
} 

Answer 2

你想這樣的：

List<string> allUrls = allProducts.SelectMany(p => p.GetPublishedUrls()).ToList(); 

Answer 3

給一個的SelectMany去 - 這應返回一個IEnumerable，如果我正確讀取您的代碼段。

IEnumerable<string> publishedUrls = allProducts.SelectMany(p => p.GetPublishedUrls()); 

Answer 4

不太清楚我明白你的問題，但如果找你試圖創造它的每個項目都有產品展示名和URL列表，這裏的代碼：

var res = from p in products.AsQueryable（） select new {ProductName = p.Name，ProductUrls = p.Urls};

Answer 5

代碼：

class Product 
{ 
    public string DisplayName; 
    public string URL; 
} 


List<Product> allProducts = new List<Product>(); 

allProducts.Add(new Product { DisplayName = "A", URL = "A1" }); 
allProducts.Add(new Product { DisplayName = "A", URL = "A2" }); 
allProducts.Add(new Product { DisplayName = "A", URL = "A3" }); 

allProducts.Add(new Product { DisplayName = "B", URL = "B1" }); 
allProducts.Add(new Product { DisplayName = "B", URL = "B3" }); 

var pGroups = from p in allProducts 
       group p by p.DisplayName into g 
       select new { DisplayName = g.Key, URLList = g }; 

foreach (var p in pGroups) 
{ 
     Console.WriteLine("Product Name: " + p.DisplayName); 
     foreach (var u in p.URLList) 
     { 
      Console.WriteLine(" URL: " + u.URL); 
     } 
} 

輸出：

Product Name: A 
    URL: A1 
    URL: A2 
    URL: A3 
Product Name: B 
    URL: B1 
    URL: B3