我該如何將這個foreach循環轉換爲linq？

Question

我對Linq很新。我想將這些代碼行轉換爲linq lambda表達式，如果有道理，我該如何實現？

foreach (var Type in Essay.Text) 
{ 
    string text = 
      $"{"here is result"}\n{method(Type)}"; 
    if (text.Length <= 20 && !string.IsNullOrEmpty(method(Type))) 
    { 
      Essay.Total += text; 
    } 
} 

Answer 1

隨着Resharper幫助：

Essay.Total = string.Concat(
      Essay.Text.Select(Type => new {Type, text = $"{"here is result"}\n{method(Type)}"}) 
       .Where(@t => @t.text.Length <= 20 && !string.IsNullOrEmpty(method(@t.Type))) 
       .Select(@t => @t.text) 
      ); 

Answer 2

事情是這樣的：

foreach (var type in from type in Essay.Text 
     let text = $"{"here is result"}\n{method(Type)}" 
     where text.Length <= 20 && !string.IsNullOrEmpty(method(Type)) select type) 
{ 
    Essay.Total += type; 
} 

Answer 3

幾個要點：

• 沒有理由調用方法兩次，j烏斯季緩存它通過使用讓
• 您還可以構建最終的字符串

這應該爲你做這項工作前檢查文本的長度：

var texts = from type in essay.Text 
      let methodResult = method(type) 
      where !string.IsNullOrEmpty(methodResult) 
      let text = $"here is result\n{methodResult}" 
      where text.Length <= 20 
      select text; 

essay.Total += string.Concat(texts);