怎样判断一个窗体已经建立(20分)

嫩

嫩手

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• 2002-11-14

• #1

我的意思是：在主窗体上放一个按钮，点击则显示一个窗体，如果该窗体已经显示出来，
则把已经显示的窗体放到最前面，如果没有显示，则显示出来，应该不难吧

 

K

kingdeezj

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• 2002-11-14

• #2

if not Assigned(form1) then
form1:= Tform1.Create(Application)
else
form1.Show;

 

Y

ysai

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• 2002-11-14

• #3

procedure OpenForm(FormClass: TFormClass;
var AForm;
AOwner:TComponent=nil);
//根据窗口类名建立窗口,如果窗口存在则只激活它
var
i: integer;
Child:TForm;
begin
for i := 0 to Screen.FormCount -1 do
if Screen.Forms.ClassType=FormClass then
begin
Child:=Screen.Forms;
if Child.WindowState=wsMinimized then
Child.WindowState:=wsNormal;
Child.BringToFront;
Child.Setfocus;
TForm(AForm):=Child;
exit;
end;
Child:=TForm(FormClass.NewInstance);
TForm(AForm):=Child;
if not assigned(aowner) then
aowner:=application;
Child.Create(AOwner);
end;

 

L

lcl_003

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GUEST, unregistred user!

• 2002-11-14

• #4

if application.findcomponet('form1')<>nil then
begin
form1:=Tform1.create(application);
form1.show;
end
else
form1.show;

 

J

jsxjd

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GUEST, unregistred user!

• 2002-11-14

• #5

初始化为 nil

 

D

dragonlee007

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GUEST, unregistred user!

• 2002-11-15

• #6

form1.handle := nil ?

 

Y

yjred

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-11-18

• #7

直接form1.show;即可

 

C

Crazyz

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-11-18

• #8

1.Assigned(form1)为false
2. Form1<>nil

 

嫩

嫩手

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-11-22

• #9

不行呀，还有别的办法吗？

 

W

wlmmlw

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GUEST, unregistred user!

• 2002-11-22

• #10

哪不行？
给出代码或是错误提示！！！！！

 

Z

zw84611

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GUEST, unregistred user!

• 2002-11-22

• #11

你要在Form2的OnDestroy加一句Form2 := nil；
然后就可以
if Assigned(Form2) then
或if Form2<>nil then
Form2.Show else
Form2 := TForm2.Create(Application);

 

B

BADBOYNET

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• 2002-11-25

• #12

ysai怎么跟我写的一样.

 

饿

饿狼传说

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• 2002-11-25

• #13

var
Hwnd :Thandle;
begin
Hwnd := findwindow('form2','project1');
if Hwnd <> 0 then
begin
setforegroundwindow(Hwnd);
end
else
form2.show;
end;

 

Z

zqflying

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GUEST, unregistred user!

• 2002-11-25

• #14

定义一全局过程或函数（即在type之外，如在var form1: Tform1的下一行）：
procedure MyForm(Aowner:Tcomponent);
然后在implementation下面实现之：
procedure MyForm(Aowner:Tcomponent);
begin
if not assigned(from1) then
（假设窗体名字为form1）
from1:= Tfrom1.Create(aowner);
from1.show;
end;
为节省内存，最好在FormClose中释放该窗体：
Action := caFree;
from1 := nil;
调用该窗体时使用MyForm(self);。

 

W

who am i?

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-11-27

• #15

试试这个!
if not assigned(form1) then
begin
form1:=application.createform(tform1,form1);
end;
form1.show;

 

B

bike

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• 2002-11-27

• #16

老兄,有findcomponet函數的都行的,自已試試吧!
那個OPENFORM怎麼連名字都跟我一樣呢?

 

W

wlmmlw

Unregistered / Unconfirmed

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• 2002-11-27

• #17

还没有结贴啊，兄弟！

 

Y

YFeral

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• 2002-11-27

• #18

参考http://www.delphibbs.com/delphibbs/dispq.asp?lid=1433671它吧，我想你的问题
同这个一样。

 

J

jesse.zhou

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-11-27

• #19

if not form1.showing then
form1.show;

 

C

cdpclj

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• 2002-11-27

• #20

同 lcl_003