custom sort method in Delphi to sort list of strings

delphi, delphi-2010, sorting, string

Solution

You can use the same compare function that Explorer uses, namely `StrCmpLogicalW`.

function StrCmpLogicalW(psz1, psz2: PWideChar): Integer; stdcall;
  external 'shlwapi.dll';

function StrCmpLogical(const s1, s2: string): Integer;
begin
  Result := StrCmpLogicalW(PChar(s1), PChar(s2));
end;

If you have your strings in a `TStringList` instance then you can use its `CustomSort` method. This expects a compare function of this form:

TStringListSortCompare = function(List: TStringList; 
  Index1, Index2: Integer): Integer;

So, feed `CustomSort` this function:

function StringListCompareLogical(List: TStringList; 
  Index1, Index2: Integer): Integer;
begin
  Result := StrCmpLogical(List[Index1], List[Index2]);
end;

Problem

I am trying to sort a list of files (they are stored as list of strings) in Delphi whose names look like below ``` a_1.xml a_20.xml a_10.xml a_2.XML ``` when i use quick sort to `sort` the file names, it sorts the file names as below ``` a_1.xml a_10.xml a_2.xml a_20.XML ``` But, I want the file names to be sorted in the below fashion ``` a_1.xml a_2.xml a_10.xml a_20.XML ``` Any help will be greatly appreciated.

Original source