User-defined variable types

Also note that Jure is doing more in his sample than what is done in your sample. For example, you have the numbers 1..256 whereas Jure is showing you that it is better to use symbolic names. It is not necessary to do that in C# but most experienced programmers do things like that (use symbolic names) because they know from experience that it is often easier in the future. It is possible to do the equivalent of what Delphi does in less C# code so I wanted to make it clear that part of the reason that Jure's sample is so much larger is because Jure is showing you a sample of what should be done. The thing I don't know is the details of what Delphi does so I would be reluctant to provide a specific answer since I cannot be sure it would be equivalent. I don't know Delphi so I don't know what happens if a TNumColors object is set to a value that is outside the limits; Jure's code makes some assumptions about what should be done but if that is inconsistent with what Delphi does then I would try to get clarification of what Delphi does before posting something specific.

You can do this:

int range_size = 256;
int range_start = 1;

int temp = /* your calculation */ - range_start
numColors = temp % range_size + range_start

and you can, for example, pack all this into a property:

private int num_colors;
private int range_size = 256;
private int range_start = 1;
public int NumColors { get { return num_colors; } set { num_colors = (value - range_start) % range_size + range_start; } }

so now, you can simply write:

NumColors *= 1000;

and it would set NumColors (num_colors indirectly) to your selected range (1-256).

But, modulo doesn't work as you want it to with negative numbers in your case. -1000 % 256 will return -1000, so you need to do 257 - |-1000| % 256, which in code is:

        public int NumColors {
            get { return num_colors; }
            set
            {
                value -= range_start;
                if (value < 0)
                    num_colors = range_size - (-value % range_size) + range_start;
                else
                    num_colors = value % range_size + range_start;
            }
        }

and now you can do this:

NumColor -= 1000;