为什么创建完TXT文件打开出错？该如何处理

为什么创建完TXT文件打开出错？

Delphi(Pascal) code

 
 procedure TForm1.Button1Click(Sender: TObject); 
 var txt :TextFile; 
 begin 
   filecreate('D:\bb.txt'); 
   AssignFile(txt, 'D:\bb.txt'); 
     Append(txt); 
     Writeln(txt,'ErrorTime:'); 
     CloseFile(txt); 
 

Delphi(Pascal) code

procedure TForm1.Button1Click(Sender: TObject);var  txt :TextFile;  i: Integer;begin  i:= filecreate('D:\bb.txt');  FileClose(i);  AssignFile(txt, 'D:\bb.txt');  Append(txt);  Writeln(txt,'ErrorTime:');  CloseFile(txt);end;
[解决办法]
是多线程访问这个文件的吗?不先判断一下这个文件存不存在呀?
[解决办法]
Delphi(Pascal) code
procedure TForm1.Button1Click(Sender: TObject);var  txt :TextFile;begin   AssignFile(txt,'D:\bb.txt');   if FileExists('D:\bb.txt') then     Append(txt)   else     ReWrite(txt);   Writeln(txt,'ErrorTime:');   CloseFile(txt);end;
[解决办法]
  try
   if FileExists('D:\bb.txt') = False then
   begin
     i :=FileCreate('D:\bb.txt');
     FileClose(i);
   end;
   AssignFile(txt,'D:\bb.txt');
   Append(txt);
   Writeln(txt,'ErrorTime:');
   finally
      CloseFile(txt);
     end;


[解决办法]
帮助里这么写
Do not use AssignFile on a file variable that is already open
[解决办法]
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帮助里这么写
Do not use AssignFile on a file variable that is already open