应该是WideSTring的问题,这样试试
function OpenFile(Str:WideString):WideString;
begin
Result:=LeftStr(Str,10);
end;
procedure TForm1.Button1Click(Sender: TObject);
var
FileStr:WideString;
begin
if OpenDialog1.Execute then
FileStr:=OpenFile(OpenDialog1.FileName);
ShowMessage(FileStr);
end;
function OpenFile(Str:String):String;
begin
Result:=LeftStr(Str,10);
end;
procedure TForm1.Button1Click(Sender: TObject);
var
FileStr:String;
begin
if OpenDialog1.Execute then
FileStr:=OpenFile(OpenDialog1.FileName);
ShowMessage(FileStr);
end;