| 发表于：2007-11-17 18:02:39 楼主 |
查询数据库，长时间等待时的动态提示，我自己做了一个，但有个问题：当执行一段存储过程时，若抛出错误（raiserror)，那么在程序中得到的message并不正确。程序代码如下：
----------------------------------------过程代码---------------------------
create procedure sp_testproc --mssql2000
as
begin
raiserror（'其它用户正在进行数据处理，请稍后！',16,1);
end
---------------------------------提示窗口的pas，没有任何代码-------------------
unit umsgbox;
interface
uses
windows, messages, sysutils, variants, classes, graphics, controls, forms,
dialogs, extctrls, comctrls, gifimage, stdctrls;
type
tmsgbox = class（tform)
panel1: tpanel;
image1: timage;
label1: tlabel;
private
{ private declarations }
public
{ public declarations }
end;
var
msgbox: tmsgbox;
implementation
{$r *.dfm}
end.
---------------------------------------执行sql的线程pas-----------------------------
unit umessageboxthread;
interface
uses
classes, sysutils, windows;
type
tmessageboxthread = class（tthread)
private
{ private declarations }
protected
procedure ＥＸＥＣute; override;
public
proc:pointer;
errmsg:string;
end;
implementation
{ important: methods and properties of objects in visual components can only be
used in a method called using synchronize, for example,
synchronize（updatecaption);
and updatecaption could look like,
procedure updateform.updatecaption;
begin
form1.caption := 'updated in a thread';
end; }
{ updateform }
procedure tmessageboxthread.ＥＸＥＣute;
var
p:procedure;
begin
{ place thread code here }
if proc <> nil then begin
p:=proc;
try
p;
except
on e:exception do errmsg:=e.message;
end;
end;
suspend;
end;
end.
-----------------------------------------主程序------------------------------------
//用线程后台执行sql的过程
procedure showmessagebox（text:string;proc:pointer);
var
msgthd:tmessageboxthread;
msgbox:tmsgbox;
errmsg:string;
begin
application.mainform.enabled:=false;
msgbox:=tmsgbox.create（application);
msgbox.label1.caption:=text;
msgbox.show;
msgthd:=tmessageboxthread.create（true);
msgthd.proc:=proc;
msgthd.resume;
while not msgthd.suspended do begin
application.processmessages;
sleep（10);
end;
errmsg:=msgthd.errmsg;
msgthd.terminate;
msgthd.destroy;
msgbox.close;
msgbox.destroy;
application.mainform.enabled:=true;
application.bringtofront;
if errmsg <> emptystr then
raise exception.create（errmsg); //// < < <-----------------线程内捕获的异常消息不正确
end;
procedure u;
begin
form1.sqlstoredproc1.ＥＸＥＣproc;
end;
procedure tform1.button1click（sender: tobject);
begin
showmessagebox（'正在审核[msd0012132]...',@u);
end;
procedure tform1.button2click（sender: tobject);
begin
try
u;
except
on e:exception do showmessage（e.message); //// < < <-----------------显示正常
end;
end;
为什么线程捕获的消息和主进程中捕获的不一样，如果要在查询数据时，显示一个动态的gif或avi，还有其他方法吗？ |
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