Question

delphi 以下代码查询按钮第1次点击报file not found错误，点击第2次以后就正常查询出来了，搞不懂为什么

var
Form1: TForm1;
mmo1:string;

implementation
{$R *.dfm}
procedure TForm1.Button2Click(Sender: TObject);
var
SN:string;
begin
begin
if Memo1.Lines.count>1000 then
ShowMessage('警告:查询数不能超过1000')
else
clientdataset1.Close;
mmo1:=copy(memo1.Text,1,Length(Memo1.Text)-3);
clientdataset1.CommandText:='select * from t1 where serial_number in ('+mmo1+');
clientdataset1.Open;
label3.Caption:=inttostr(clientdataset1.RecordCount);
end;
end;
procedure TForm1.btn1Click(Sender: TObject);
var
fl:textfile;
sn1:string;
i:integer;
begin
Memo1.Clear;
dlgOpen1.FileName:='';
if dlgopen1.Execute then
begin
assignfile(fl,dlgopen1.FileName);
end;
reset(fl);
while not Eof(fl) do
begin
readln(fl,sn1);
memo1.Lines.Add(QuotedStr(sn1)+',');
end;
closefile(fl);
end;

Answer 1

跟踪一下看看那条语句出的错。

Answer 2

if dlgopen1.Execute then改成下面的试试看
if (dlgopen1.Execute) and (dlgopen1.FileName <> '') then