Question

我的应用程序中有一个处理生成的异常的过程。事实证明，如果在 untThreadDSR 中生成异常，则异常不会被它应该操作它的过程捕获。如果异常是从任何其他表单生成的，则该过程会正确捕获它。

该过程位于主DataModule中：

...
private
  { Private declarations }
  procedure HandleExceptions(Sender: TObject; E: Exception);
...

procedure DM.HandleExceptions(Sender: TObject; E: Exception);
begin
  if pos('UNIQUE KEY',E.Message) <> 0 then
  begin
    if pos('UNQ_CUSTOMER_NAME',E.Message) <> 0 then
      MsgMsg('Customer already registered.',2)
    else if pos('UNQ_USERS_LOGIN',E.Message) <> 0 then
      MsgMsg('User already registered.',2);
  end else
  if pos('ERROR_DATASYS',E.Message) <> 0 then
    MsgMsg('The Server Date is incorrect. Please contact your network administrator!',2)
  else //Other messages will be sent to Support
    SendReport(E.Message, V_COMPANY, V_LOGIN, V_APP_VERSION, Sender);
end;

untThreadDSR：

unit untThreadDSR;

interface

uses
  Classes, SysUtils, Messages, Windows, Forms;

type
  TThreadDSR = class(TThread)
  procedure DSR_Start;
  private
    { Private declarations }
  protected
    procedure Execute; override;
  end;

implementation

uses untDM;

procedure TThreadDSR.DSR_Start;
begin
  //I put this intentionally just to generate an exception
  StrToInt('');
  //If this is on any other form, the exception is caught by "HandleExceptions", but from here on out!
end;

procedure TThreadDSR.Execute;
begin
  Synchronize(DSR_Start);
end;

end.

TThreadDSR的调用方式如下：

procedure TFrmDSR.btnExecuteClick(Sender: TObject);
var
  Thread: TThreadDSR;
begin
  Thread := TThreadDSR.Create(true);
  Thread.FreeOnTerminate := true;
  Thread.Resume;
end;

Answer 1

异常不跨越线程边界。如果未捕获的异常转义TThread.Synchronize()调用的过程，Synchronize()将捕获异常并在工作线程的上下文中重新引发它。如果Execute()随后未捕获异常，则线程将终止并将异常分配给TThread.FatalException属性。

您可以使用TThread.OnTerminate事件（在主线程的上下文中调用）将FatalException传递给您的HandleExceptions()程序。

如何捕获Thread中生成的异常以便能够操作它

1 个答案: