The variable ‘MyException’ is declared but never used

1. You can remove it like this:

   try
   {
       doSomething()
   }
   catch (AmbiguousMatchException)
   {
       doSomethingElse()
   }
   

2. Use warning disable like this:

   try
   {
       doSomething()
   }
   #pragma warning disable 0168
   catch (AmbiguousMatchException exception)
   #pragma warning restore 0168
   {
       doSomethingElse()
   }
   

Other familiar warning disable

#pragma warning disable 0168 // variable declared but not used.
#pragma warning disable 0219 // variable assigned but not used.
#pragma warning disable 0414 // private field assigned but not used.