Help me to know the execution time

I want to know the execution time of an iteration in my program I try to use

using system.diagnostics.stop watch
sw.start ()

sw.stop ()

but it displays an error

What error? Is it saying something like NOT_IMPLEMENTED for example ? That alone should give you the answer.

Just use the system time and calculate the difference between two events. Use the ticks to get highest accuracy.

the error
VS is can not know a library

using system.diagnostics.stop watch

knowing that I have the library System

The .NET Micro Framework is only a subset of the Full .NET Framework, so some classes are not supported. Fortunately, there are several entries in Codeshare that can do what you want.

https://www.ghielectronics.com/community/codeshare/search?q=stopwatch

:clap: thank you

You can also try using Object Browser to look at the references to see what they expose.