Unique Object

Question

I am trying to come up with a way to only add a part number if it does not exist. Can you give the best way to do this below using the
part number object?

colorfile.PartNumbers.Add(new Color_PartNumber() { colorNumber = colorPartNumber.partNumber });

Vulpes · Answer

No not AFAICS. I can't see any alternative to looking through the PartNumbers collection to see whether there's already a Color_PartNumber object whose colorNumber property is equal to the proposed new value. In fact it would be more efficient to do this using 'normal' code rather than LINQ as you can break immediately when an existing duplicate is found rather than carrying on and looking for more.

Vulpes · Answer

Rather than use normal code you could use Any rather than Count which probably breaks (internally) when it finds an element which satisfies the predicate: bool alreadyExists = colorfile.PartNumbers.Any(pn => pn.colorNumber == colorPartNumber.partNumber); if (!alreadyExists) { colorfile.PartNumbers.Add(new Color_PartNumber() { colorNumber = colorPartNumber.partNumber }); }

Vulpes · Answer

Try: int count = colorfile.PartNumbers.Count(pn => pn.colorNumber == colorPartNumber.partNumber); if (count == 0) { colorfile.PartNumbers.Add(new Color_PartNumber() { colorNumber = colorPartNumber.partNumber }); }

David Smith · Answer

Is there another way to do this without using the int count below vuples. int count = colorfile.PartNumbers.Count(pn => pn.colorNumber == colorPartNumber.partNumber); if (count == 0) { colorfile.PartNumbers.Add(new Color_PartNumber() { colorNumber = colorPartNumber.partNumber }); }

David Smith · Answer

Is there another way to do it without the int. Also can you check out my last thread before this I am trying to rewrite that entire method. I am trying to come up with a way of not using the array elements. I want to do the incrementing. I try to stay away from incrementing. thats c++ mentality. Check out my last thread call Save XML data to File