如何判断一个窗体已经被创建了???

Question

if Assigned(Form1) then
  // 已创建

Answer 1

if assigned(frm) then
  showMessage('已创建');

Answer 2

if fangtaicx = nil then
  begin
    tfangtaicx.Create(self);
    fangtaicx.show;
    fangtaicx.Left:=66;
    fangtaicx.Top:=10;
  end;
当然，fangtaicx为全局变量

Answer 3

if Assigned(Form1) then
  Form1.setfocus;

Answer 4

if fangtaicx=nil then
   fangtaicx:=Tfangtaicx.create(nil);
fangtaicx.show;
fangtaicx.release;
fangtaicx:=nil;

Answer 5

if fangtaicx = nil then
  begin
    tfangtaicx.Create(self);
    fangtaicx.show;
    fangtaicx.Left:=66;
    fangtaicx.Top:=10;
  end
else fangtaicx.show;

Answer 6

//聲明
var
  SYS_WORK_SFORM : TForm;  //用以判斷窗體是否運行
//運用
  if SYS_WORK_SFORM = nil then
    begin
      SYS_WORK_SFORM := TfrmSysWork.Create(Application);
      SYS_WORK_SFORM.Show;
    end;