Uses Winsock;

var
  ColumnToSort: Integer;
  LastSorted: Integer;
  SortDir: Integer;

procedure TForm1.ListView1ColumnClick(Sender: TObject; Column: TListColumn);
begin
  ColumnToSort := Column.Index;
  if ColumnToSort = LastSorted then
    SortDir := 1 - SortDir
  else
    SortDir := 0;
  LastSorted := ColumnToSort;
  (Sender as TCustomListView).AlphaSort;
end;

procedure TForm1.ListView1Compare(Sender: TObject; Item1,
  Item2: TListItem; Data: Integer; var Compare: Integer);
var
  TempStr, TextToSort1, TextToSort2: String;
begin
//Texte zuweisen
  if ColumnToSort = 0 then
  begin
    TextToSort1 := Item1.Caption;
    TextToSort2 := Item2.Caption;
  end //if ColumnToSort = 0 then
  else
  begin
    TextToSort1 := Item1.SubItems[ColumnToSort - 1];
    TextToSort2 := Item2.SubItems[ColumnToSort - 1];
  end; //if ColumnToSort <> 0 then

//Je nach Sortierrichtung evtl. Texte vertauschen
  if SortDir <> 0 then
  begin
    TempStr := TextToSort1;
    TextToSort1 := TextToSort2;
    TextToSort2 := TempStr;
  end; //if SortDir <> 0 then

//Texte je nach Tag der Spalte unterschiedlich vergleichen
  case (Sender as TListView).Columns[ColumnToSort].Tag of
//Integer-Werte
    1: Compare := StrToInt(TextToSort1)-StrToInt(TextToSort2);
//Float-Werte
    2: begin
      Compare := 0;
      if StrToFloat(TextToSort1) > StrToFloat(TextToSort2) then
        Compare := Trunc(StrToFloat(TextToSort1)-StrToFloat(TextToSort2))+1;
      if StrToFloat(TextToSort1) < StrToFloat(TextToSort2) then
        Compare := Trunc(StrToFloat(TextToSort1)-StrToFloat(TextToSort2))-1;
    end; //2
//DateTime-Werte
    3: begin
      Compare := 0;
      if StrToDateTime(TextToSort1) > StrToDateTime(TextToSort2) then
        Compare := Trunc(StrToDateTime(TextToSort1)-StrToDateTime(TextToSort2))+1;
      if StrToDateTime(TextToSort1) < StrToDateTime(TextToSort2) then
        Compare := Trunc(StrToDateTime(TextToSort1)-StrToDateTime(TextToSort2))-1;
    end; //3
//IPs
    4: begin
      Compare := 0;
      if ntohl(inet_addr(PAnsiChar(TextToSort1))) > ntohl(inet_addr(PAnsiChar(TextToSort2))) then
        Compare := Trunc(ntohl(inet_addr(PAnsiChar(TextToSort1)))-ntohl(inet_addr(PAnsiChar(TextToSort2))))+1;
      if ntohl(inet_addr(PAnsiChar(TextToSort1))) < ntohl(inet_addr(PAnsiChar(TextToSort2))) then
        Compare := Trunc(ntohl(inet_addr(PAnsiChar(TextToSort1)))-ntohl(inet_addr(PAnsiChar(TextToSort2))))-1;
    end; // 4
//Alles andere sind Strings
    else
      Compare := CompareText(TextToSort1,TextToSort2);
  end; //case (Sender as TListView).Columns[ColumnToSort].Tag of
end; //procedure TForm1.ListView1Compare