Changing element value in List<T>.ForEach ForEach method

Question

I have the following code:

newsplit.ToList().ForEach(x => x = "WW"); 

I would expect that all elements in the list are now "WW" but they are still the original value. How come? What do I have to do different?

Answer 1

Assuming that newsplit is an IEnumerable<string>, you want:

newsplit = newsplit.Select(x => "WW"); 

The code that you currently have is equivalent to the following:

foreach(string x in newsplit.ToList()) {     AssignmentAction(x); }  ...  public static void AssignmentAction(string x) {     x = "WW"; } 

This method won't modify x because of the pass-by-value semantics of C# and the immutability of strings.