Title: Find the number of files or the oldest file matching a file spec
Question: How do I count the number of files matching c:\temp\*.dat?
What is the oldest file matching c:\windows\*rep.*?
Answer:
{This unit contains a form with:
a Button
an EditBox
If you type into the edit box a string
such as c:\windows\*.dll, then
click on the button - a message box
will appear that shows text like this:
The oldest file matching c:\windows\*.dll
is c:\windows\somefile.dll
}
unit oldestfileu;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics,
Controls, Forms, Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
function FileCount(FileSpec: string): longint;
function GetOldestFile(FileSpec: string): string;
implementation
{$R *.DFM}
{This function can be used to return the name
of the oldest file which matches the FileSpec}
function GetOldestFile(FileSpec: string): string;
var
SR: TSearchRec;
DosError: integer;
Oldest: string;
OldestDTime: TDateTime;
begin
{if there is more than one file that matches FileSpec
then find the one with the oldest date}
if FileCount(FileSpec)1 then
begin
DosError := FindFirst(FileSpec, faAnyFile-faDirectory, SR);
if DosError=0 then
begin
Oldest := ExtractFilePath(FileSpec)+SR.Name;
OldestDTime := FileDateToDateTime(SR.Time);
while FindNext(SR)=0 do
begin
if FileDateToDateTime(SR.Time) begin
Oldest := ExtractFilePath(FileSpec)+SR.Name;
OldestDTime := FileDateToDateTime(SR.Time);
end;
end;
Result := Oldest;
end;
end
else {if there is only one file then return its name}
begin
DosError := FindFirst(FileSpec, faAnyFile, SR);
if DosError=0 then
begin
Result := ExtractFilePath(FileSpec)+SR.Name;
end
else {if there are no matching files then return blank}
Result := '';
end;
end;
{This function can be used to return the number
of files in a directory which match the FileSpec}
function FileCount(FileSpec: string): longint;
var
SR: TSearchRec;
DosError: integer;
c: longint;
begin
c := 0;
DosError := FindFirst(FileSpec, faAnyFile, SR);
if DosError=0 then
begin
if (SR.Name'.') and (SR.Name'..') then inc(c);
while FindNext(SR)=0 do
begin
if (SR.Name'.') and (SR.Name'..') then inc(c);
end;
end
else
c := 0;
FileCount := c;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
ShowMessage('The oldest file matching '+Edit1.Text
+' is: '+GetOldestFile(Edit1.Text));
end;
end.