Getting a process's ram usage

I found this on msdn and it is working

System.Diagnostics.Process proc = ...; // assign your process here :-)

int memsize = 0; // memsize in KB
PerformanceCounter PC = new PerformanceCounter();
PC.CategoryName = "Process";
PC.CounterName = "Working Set - Private";
PC.InstanceName = proc.ProcessName;
memsize = Convert.ToInt32(PC.NextValue()) / (int)(1024);
PC.Close();
PC.Dispose();

If you are purely interested in physical memory, you probably want WorkingSet64, which gives "the amount of physical memory allocated for the associated process." Understand that this value constantly fluctuates, and the value this call gives you may not be up to date. You may also be interested in PeakWorkingSet64, which gives "the maximum amount of physical memory used by the associated process."