Question

I wish I had the following method

int num;  
int.TryParse("5",out num, 10);

Which will do the same as TryParse, but addtional if the parsing fails,
the out parameter will get the defualt value 10

Can I implement it?

With extension methods I can implement the following:

int num;
num.TryParse("5",out num, 10);

But this look different than the rest of the TryParse methods..

Answer 1

You cannot add static methods to existing classes, but you can add your own static method to your own class, for example:

public static class MyConversions
{
   public static bool TryParse(string value, out int num, int defaultValue)
   {
     ...
   }
}