求助：这段多线程代码为什么不稳定？
先描述一下情况：
程序用一按钮启动定时器（触发间隔5秒），定时器内循环创建8个线程，传递多个参数。线程函数就是在内存里面创建一个位图，然后写字。程序运行几分钟，或十几分钟后就会崩溃，无法定位出错点。
线程内的代码都是局部变量，也没有操作窗口上面的控件，我就不明白为什么不稳定？
初学delphi不久，折腾了一个星期无果，来此求助。不胜感激。
全部代码就这么点：
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Timer1: TTimer;
Image1: TImage;
Button2: TButton;
Image2: TImage;
Button3: TButton;
procedure Button1Click(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
PParData = ^TParData;
TParData = record
cardNum:Integer;
stationName:string;
trunkNo:string;
relatedFormID:string;
materialName:string;
taskState:string;
materialNum:Integer;
sl1:integer;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
Timer1.Enabled:=True;//启动定时器
end;
function LEDThread(AParData: PParData):Boolean; stdcall;
var
txtRect: Trect;
fontObj: Longint;
hBrush: Longint;
memDC: Longint;
hDisplayDC: Longint;
newBitmap: Longint;
oldpBitmap: Longint;
myFont: Longint;
oneItem:string;
begin
hDisplayDC := GetDC(0);
memDC := CreateCompatibleDC(hDisplayDC);
newBitmap := CreateCompatibleBitmap(hDisplayDC, 320, 96);
oldpBitmap := SelectObject(memDC, newBitmap);
SetBkMode(memDC, TRANSPARENT);
hBrush := CreateSolidBrush(0);
FillRect(memDC, txtRect, hBrush);
DeleteObject(hBrush);
SetTextColor(memDC, 255);
myFont := CreateFont(14, 7, 0, 0, 0, 0, 0, 0, GB2312_CHARSET,
OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, PROOF_QUALITY, FF_ROMAN, '宋体');
fontObj := SelectObject(memDC, myFont);
DeleteObject(fontObj);
with txtRect do // 出口
begin
Left := 130;
Top := 16 * 0;
Right := 320;
Bottom := 16 * 1;
end;
oneItem:=AParData.stationName;
//尝试用TextOut和DrawText两个函数，效果都差不多
TextOut(memDC,txtRect.Left, txtRect.Top ,PChar(oneItem),Length(oneItem));
//DrawText(memDC, PChar(AParData.stationName), -1, txtRect,DT_SINGLELINE Or DT_CENTER Or DT_VCENTER);
//如果函数代码到此结束，观察，测试，程序是稳定的。一旦DrawText或TextOut在函数内使用大于一次，就会很不稳定
with txtRect do
begin
Left := 8;
Top := 16 * 1;
Right := 320;
Bottom := 16 * 2;
end;
oneItem:='车牌号: ' + AParData.trunkNo;
TextOut(memDC,txtRect.Left, txtRect.Top ,PChar(oneItem),Length(oneItem));
//DrawText(memDC, PChar('车牌号: ' + AParData.trunkNo), -1, txtRect,DT_SINGLELINE Or DT_LEFT Or DT_VCENTER);
with txtRect do
begin
Left := 8;
Top := 16 * 2;
Right := 320;
Bottom := 16 * 3;
end;
oneItem:='品牌: ' +AParData.materialName;
TextOut(memDC,txtRect.Left, txtRect.Top ,PChar(oneItem),Length(oneItem));
//DrawText(memDC, PChar('品牌: ' + AParData.materialName), -1, txtRect,DT_SINGLELINE Or DT_LEFT Or DT_VCENTER);
with txtRect do
begin
Left := 8;
Top := 16 * 3;
Right := 320;
Bottom := 16 * 4;
end;
oneItem:='计划出库: ' + inttostr(AParData.materialNum)+ ' 件，' + ' 已出库:' + inttostr(AParData.sl1) + ' 件';
TextOut(memDC,txtRect.Left, txtRect.Top ,PChar(oneItem),Length(oneItem));
//DrawText(memDC, PChar('计划出库: ' + inttostr(AParData.materialNum)+ ' 件，' + ' 已出库:' + inttostr(oneParData.sl1) + ' 件'), -1, txtRect,DT_SINGLELINE Or DT_LEFT Or DT_VCENTER);
with txtRect do
begin
Left := 8;
Top := 16 * 4;
Right := 320;
Bottom := 16 * 5;
end;
oneItem:='单据: ' + AParData.relatedFormID;
TextOut(memDC,txtRect.Left, txtRect.Top ,PChar(oneItem),Length(oneItem));
//DrawText(memDC, PChar('单据: ' + AParData.relatedFormID), -1, txtRect,DT_SINGLELINE Or DT_LEFT Or DT_VCENTER);
DeleteDC(memDC);
ReleaseDC(0, hDisplayDC);
DeleteObject(newBitmap);
DeleteObject(oldpBitmap);
Sleep(1000); //暂停，方便从任务管理器观察线程
Result:=True;
end;
procedure TForm1.Timer1Timer(Sender: TObject);
var i:Integer;
hThread: THandle;
ThreadID: DWord;
vParData: PParData;
begin
Timer1.Enabled:=false;
for i := 0 to 7 do //创建8个线程
begin
ThreadID:=0;
New(vParData);
vParData.cardNum:=1;
vParData.stationName:='a';
vParData.trunkNo:='b';
vParData.relatedFormID:='c';
vParData.materialName:='d';
vParData.taskState:='e';
vParData.materialNum:=2;
vParData.sl1:=3;
hThread := CreateThread(nil, 0, @LEDThread, vParData, 0, ThreadID);
end;
Timer1.Enabled:=True;
end;
end.
[解决办法]
procedure TForm1.Button1Click(Sender: TObject);
begin
IsMultiThread := TRUE; //这里加也行
Timer1.Enabled:=True;//启动定时器
end;
[解决办法]
CreateThread创建线程后，必须把delphi的系统全局变量IsMultiThread设为TRUE，线程结束后它系统会自动把IsMultiThread设回FALSE。但是，最好的方法就是用抛弃CreateThread，而用BeginThread来创建线程，BeginThread内存会把IsMultiThread:=True。
你的代码做下面修改
function LEDThread(AParData: PParData): Boolean; // stdcall; 去掉
begin
.....
DeleteObject(oldpBitmap);
Dispose(AParData); // 这里释放内存
Sleep(100); //这个sleep不能太大，或者去掉这个sleep
Result := True;
end;
改好后，你再继续测试个把小时看看
[解决办法]
sololie 好热心哦
