Passing method using delegate

I was doing some code refactoring today and this is one of the things that fits nicely to remove those repetitive codes.

I have lines of code below as an example where I process some data based on certain key.

private void ProcessData() {     string theKey;     Key key = new Key("A", "B");                theKey = key.KeyA;     Console.WriteLine("Processing data with key : {0}", theKey);     theKey = key.KeyB;     Console.WriteLine("Processing data with key : {0}", theKey);     theKey = key.KeyA + key.KeyB;     Console.WriteLine("Processing data with key : {0}", theKey); }

This looks simple enough, but imagine what would happen if i replace “the processing data with key…” line with 20 real codes, they suddenly become 60 lines which are repetitive, doing the same thing using the key ;)

 

So this is what I came out with, create a delegate which receives Key object then create 3 new methods which have the same signature as the delegate and will have the logic to construct the key.

private delegate string AssignKeyDelegate(Key key); private string AssignKeyA(Key key) {     return key.KeyA; } private string AssignKeyB(Key key) {     return key.KeyB; } private string AssignKeyAB(Key key) {     return key.KeyA + key.KeyB; }

 

By using this, I can process the data and construct the key based on the appropriate method which is specified in the parameter using the delegate.

private void Run() {     ProcessData(new AssignKeyDelegate(AssignKeyA));     ProcessData(new AssignKeyDelegate(AssignKeyB));     ProcessData(new AssignKeyDelegate(AssignKeyAB)); } private void ProcessData(AssignKeyDelegate del) {     Key key = new Key("A", "B");                string theKey = del(key);     Console.WriteLine("Processing data with key : {0}", theKey); }

 

I provided the sample code above as a basic example only, there are many solutions that may come out with this kind of code :) The purpose is only to describe another feature that we can do with delegate.

Hope this helps :)