判断窗体、控件是否存在(50分)

Y

yubo

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• 2000-06-04

• #1

我在编一个程序需要动态创建窗体<br>如何判断它是否存在?

 

H

hpretty

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• 2000-06-04

• #2

try control[x].objectname

 

P

philips

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• 2000-06-04

• #3

 

L

liguang

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• 2000-06-04

• #4

procedure TForm1.FormCreate(Sender: TObject);<br>begin<br>&nbsp;Form2:=nil;<br>end;<br><br>procedure TForm1.Button1Click(Sender: TObject);<br>begin<br>&nbsp;if Form2=nil then<br>&nbsp; &nbsp;Form2:=TForm2.Create(Self);<br>&nbsp;Form2.Show;<br>end;<br><br>procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);<br>begin<br>&nbsp;Form2:=nil;<br>&nbsp;Action:=caFree;<br>end;<br><br>以上代码是在线写的，分都给我吧。

 

Z

zhangdamin

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• 2000-06-04

• #5

if assigned(控件名) then<br>...

 

K

Kang

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• 2000-06-04

• #6

你如果要反复创建，则在超出其作用域前Free它，并赋为nil

 

K

Kent

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• 2000-06-04

• #7

<br>procedure TForm1.Button1Click(Sender: TObject);<br>begin<br>&nbsp;if not assigned(form2) then<br>&nbsp; &nbsp;Form2:=TForm2.Create(Self);<br>&nbsp;Form2.Show;<br>end;<br><br>在onclose中action:=cafree;<br>在onDestroy中form2:=nil;<br><br>

 

M

menxin

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• 2000-06-04

• #8

给你个标准的：<br>var a:TComponent;<br>begin<br>&nbsp; a:=Application.FindComponent('form2');<br>&nbsp; if a&lt;&gt;nil then<br>&nbsp; &nbsp; ShowMessage(a.Name+' has been found!');<br>end;

 

S

SuperMMX

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• 2000-06-04

• #9

liguang 的做法比较好。

 

Y

yubo

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GUEST, unregistred user!

• 2000-06-05

• #10

多人接受答案了。