Function isAscii(NomeFile: String): Boolean;

const

Sett=2048;

var

i: Integer;

F: file;

a: Boolean;

TotSize

IncSize

ReadSize: Integer;

c: Array[0..Sett] of byte;

begin

If FileExists(NomeFile) then

begin

{$I-}

AssignFile(F

NomeFile);

Reset(F

1);

TotSize:=FileSize(F);

IncSize:=0;

a:=true;

while (IncSize begin

ReadSize:=Sett;

If IncSize+ReadSize>TotSize then ReadSize:=TotSize-IncSize;

IncSize:=IncSize+ReadSize;

BlockRead(F

c

ReadSize);

For i := 0 to ReadSize-1 do // Iterate

If (c[i]<32) and (not (c[i] in [9

10

13

26])) then a:=False;

end; // while

CloseFile(F);

{$I+}

If IOResult<>0 then Result:=False

else Result:=a;

end;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

if OpenDialog1.Execute then

begin

if isAscii(OpenDialog1.FileName) then

begin

ShowMessage(''ASCII File'');

end;

end;

end;