How do I rewrite a lambda expression in C# 2.0?

Question

MatchEvaluator evaluator = (match) =>
 {
 var splitPos = match.Value.IndexOf("=\"");
 var newValue = match.Value.Substring(0, splitPos + 2) +
 "RetrieveBuildFile.aspx?file=" +
 prefix +
 match.Value.Substring(splitPos + 2);
 return newValue;
 };

What does this code mean , I need to port this code which is in VS 2008 to VS 2005, the same is not available in VS 2005

Answer 1

c# 2.0 supports the delegate keyword, so it could be rewritten into this:

MatchEvaluator evaluator = delegate(Match match) {
 int splitPos = match.Value.IndexOf("=\"");
 string newValue = match.Value.Substring(0, splitPos + 2) +
 "RetrieveBuildFile.aspx?file=" +
 prefix +
 match.Value.Substring(splitPos + 2);
 return newValue;
};

And this is exactly the same as this:

static string OnEvaluator(Match match) {
 int splitPos = match.Value.IndexOf("=\"");
 string newValue = match.Value.Substring(0, splitPos + 2) + 
 "RetrieveBuildFile.aspx?file=" + 
 prefix + 
 match.Value.Substring(splitPos + 2);
 return newValue;
}

called with:

MatchEvaluator evaluator = OnEvaluator;

And what it is?

MSDN: Represents the method that is called each time a regular expression match is found during a Replace method operation.

http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.matchevaluator.aspx

• Justin: var is also VS2008 only - when building this in VS2005 you will need to replace var with the actual type, e.g. int in the first case and string in the second (I think).