用户注销时报Edatabaseerror错(50分)

B

babyrun

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GUEST, unregistred user!

• 2008-06-12

• #1

用户注销时报Edatabaseerror错，经单步跟踪调试，发现程序运行时不断刷新dbgrid的背景显示，当注销用户时此处便会报“Edatabaseerror错”，大家帮忙看看如何解决？

procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
begin

if Query1.FieldByName('Red').AsString = 'A' then //注销用户时，运行到这里就报错
DbGrid1.Canvas.Brush.color:=clRed;
......
DBGrid1.DefaultDrawColumnCell(Rect,DataCol,Column,State);

end;

 

H

hanpengshan_00

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• 2008-06-12

• #2

错误原因：Query1要么处于非活动状态，要么被释放了

 

老

老人家

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• 2008-06-12

• #3

if Query1.Active then
begin
if Query1.FieldByName('Red').AsString = 'A' then
DbGrid1.Canvas.Brush.color:=clRed;
......
DBGrid1.DefaultDrawColumnCell(Rect,DataCol,Column,State);
end;
你试一下吧

 

B

babyrun

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GUEST, unregistred user!

• 2008-06-16

• #4

试过了，还是不好用[!]

 

4

41426277

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GUEST, unregistred user!

• 2008-06-16

• #5

if not 窗体.showing then exit;
if not Query1.Active then exit;

if Query1.FieldByName('Red').AsString = 'A' then
DbGrid1.Canvas.Brush.color:=clRed;
......
DBGrid1.DefaultDrawColumnCell(Rect,DataCol,Column,State);

 

B

babyrun

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• 2008-06-17

• #6

不行啊！还是不好用。富翁们难道都没有遇到过类似问题？

 

Q

qq112729650

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• 2008-06-17

• #7

Query1是否存在
检查一下是否为nil

 

Z

zqw0117

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GUEST, unregistred user!

• 2008-06-18

• #8

在窗体的OnClose（或者是OnDestroy）里面写这样一句：
DBGrid1.OnDrawColumnCell := nil;
就OK了

 

B

babyrun

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2008-07-07

• #9

问题依旧，难道真的没有解决的办法？