Format Uang

type tFormatUang=Record
        Text:String;
        SelStart:Integer;
        end;

function FormatUang(input:string):tFormatUang;
var
  sRupiah: string;
  min,i,c:word; dec:boolean;
begin
        sRupiah:='';
        c:=1;
        dec:=false;

        if length(input)>0 then
        begin
        if input[1]='-' then min:=2 else min:=1;

        for i:=length(input) downto min do
        if input[i]='.' then dec:=true;

        for i:=length(input) downto min do
        begin
                if input[i] in ['0'..'9','.','-'] then
                begin
                        if input[i]='.' then
                        begin
                                dec:=false;
                                c:=0;
                        end;
                        if c=4 then
                        begin
                                if dec=false then sRupiah:=input[i]+','+sRupiah;
                                c:=1;
                        end else sRupiah:=input[i]+sRupiah;
                        if dec=false then inc(c);
                end;
        end;

        if input[1]='-' then sRupiah:='-'+sRupiah;

        end;
        FormatUang.Text := sRupiah;
        FormatUang.SelStart := length(sRupiah);
end;

Contoh :

procedure TForm1.Edit1Change(Sender: TObject);
begin
        Edit1.Text:=FormatUang(Edit1.Text).Text;
        Edit1.SelStart:=FormatUang(Edit1.Text).SelStart;
end;