如何在LINQ語句中添加if語句

Question

有人可以幫我添加下面代碼段中評論的if語句嗎？

Dictionary<string,int> toReturn; 
List<string> lookup = GetIt(); 

foreach (string test in lookup) 
{ 
    var testDictionary = ToGroupDictionary(test); 
    testDictionary.Keys.ToList().ForEach(k => 
     //if(true){add toReturn list} 
    ); 
} 

Answer 1

只需要添加花括號：

testDictionary.Keys.ToList().ForEach(k => 
{ 
    //if(true){add toReturn list} 
}); 

Answer 2

或者添加Where條款

testDictionary 
    .Keys 
    .Where(k => conditional(k)) 
    .ForEach(k => { /* something else */ });