Why does assignment operator return the assigned value in C#? [duplicate]

Question

The assignment operator in C# returns the assigned value. It's not clear where/how this feature can be helpful. Using it in a weird syntax like this can save you a line of code, but won't do any good to readbility:

   private String value;
   public void SetAndPrintValue(String value)
      PrintValue(this.value = value);
   }
   private static void PrintValue(String value) {
      /* blah */
   }

What is its purpose then?

Answer 1

Chained assignment is a staple of many languages going back to C (and probably earlier). C# supports it because it's a common feature of such languages and has some limited use—like the goto statement.

Occasionally you might see code like this:

int a, b, c;
for(a = b = c = 100; a <= b; c--)
{
    // some weird for-loop here
}

Or this:

var node = leaf;
while(null != node = node.parent) 
    node.DoStuff();

This might make some code a little more compact, or allow you to do some clever tricks, but it certainly doesn't make it more readable. I'd recommend against it in most cases.