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Suppose you have 2 values that are declared as generics, and you want to perform equality, or comparison, how would you do this?
Value1, Value2: V;
You'll need to obtain a generics comparer.
Given the declaration: LComparer: IComparer<V>;
// Here's how you obtain a comparer: LComparer := TComparer<V>.Default; // declared in System.Generics.Defaults;
Then, to compare, here's what you do:
case LComparer.Compare(Value1, Value2) of -1: ... Value1 is smaller than Value2 0: ... Value1 is equal to Value2 1: ... Value1 is greater than Value2 end;
In cases of LComparer being assigned the result of TComparer<string>.Default, you can get values less than and greater than 0, so you might want to consider another way to compare, like so:
LCompareResult := LComparer.Compare(Value1, Value2); if LCompareResult < 0 then ... else if LCompareResult = 0 then ... else if LCompareResult > 0 then ...
Thanks to fellow MVP, Stefan G who pointed out that for string comparers, you can get results having negative and positive values, not just -1 and +1.