1. If you want your program to handle exceptions correctly, please refer to the sysutils.pas unit, otherwise even if the program uses TRY. . . Except. . . You cannot capture an exception correctly.
2. A way to define a constant string
ResourceString
AA = 'aaaa';
Raise Exception.createres (@AA);
3. Initialization of string constant array
Const constarray: array [0..2] of string = ('first', 'second', 'third');
4. Structural initialization
TYPE TSTRUCTINIT = Record
A1: Integer;
A2: array [0..2] of integer;
END;
Const m_structinit: tstructinit = (A1: 0; A2: (0, 1, 2));
5. The length of the multi-dimensional array
Var Array2: Array of Array of Integer;
SETLENGTH (Array2, 2, 2);
6. The space opened with Create and New exists in the heap, and cannot be automatically released. It is recommended to use freeandnil release, parameters, and local variables existing in the stack, automatically release.
7. SIZEOF is not suitable for objects, returns to always 4; the fixed type can be returned correctly.
8. Create (NIL) requires manual release, Creat (Self) will be released as the owner's release.
9. Dynamic changes the value of the defined constant
Procedure ChangeConst (const const; var value; size: integer);
Begin
Move ((@ value) ^, (@ constant) ^, size);
END;
10. Cyclic use of DOWNTO when deleting operations, will avoid errors.
11. Chinese characters ASCII code> 128, can use it to judge whether it is Chinese characters
12. DLL write, you need to use the ShareMem unit to reference BorlandMM.DLL memory management.
13. PostMessage only places the message in the message queue and needs to wait in line.
SendMessage Winding the message queue directly to the window process, waiting to return the message processing return value.
14. Mouse move into the transfer message: cm_mouseeenter, cm_mouselave
15. Shutdown message WM_QUERYENDSESSION
16. You can create a floating form using ThintWindow and class method ActivateHint.
17. Tune the file properties dialog
Uses shellapi;
Function ShowFileProperties (filename: string; wnd: hwnd): boolean;
VAR
SFI: TshellexecuteInfo;
Begin
WITH SFI DO
Begin
CBSIZE: = SizeOf (SFI);
LPFILE: = Pansichar (filename);
WND: = WND;
FMASK: = SEE_MASK_NOCLOSEPROCESS or see_mask_invokeidlist or see_mask_flag_no_ui;
LPVERB: = Pansichar ('Properties');
LPIDLIST: = NIL;
LPDIRECTORY: = NIL;
Nshow: = 0;
Hinstapp: = 0;
LPParameters: = NIL;
DwhotKey: = 0;
Hicon: = 0; HKEYCLASS: = 0;
HPROCESS: = 0;
LPClass: = NIL;
END;
Result: = shellexecuteEx (@sfi);
END;
Procedure TFORM1.BUTTON1CLICK (Sender: TOBJECT);
Begin
ShowFileProperties ('C: /AA.TXT', HANDLE);
END;
18. Change the system time
Uses Windows, Dialogs, Forms;
Var myTime: TsystemTime;
Begin
Fillchar (MyTime, SizeOf (MyTime), # 0);
Mytime.wyear: = 2003;
Mytime.wmonth: = 06;
MyTime.wday: = 01;
IF not setsystem (mytime) THEN
ShowMessage ('failure');
END;
19. Copy the folder XCOPY
Procedure Xcopy (SourceDir, DestinationDir: String);
VAR
Search: tsearchrec;
Re: Word;
Begin
SourceDir: = SOURCEDIR '/';
REC: = Findfirst (SourceDir '*. *', Faanyfile, Search;
While REC = 0 DO
Begin
If Search.Name [1] <> '.' Then
Begin
IF (Search.attr and Fadirectory) = Fadirectory Then
Begin
Windows.createdIRectory (Pchar (DestinationDir '/' Search.Name), NIL);
FileSetattr (DestinationDir '/' Search.Name, Filegetattr (SourceDir '/' Search.Name);
X_copy (SourceDir '/' Search.Name, DestinationDir '/' Search.Name);
end
Else
Begin
CopyFile (Pchar (SourceDir '/' Search.Name), Pchar (DestinationDir '/' Search.Name), True;
FileSetattr (DestinationDir '/' Search.Name, Filegetattr (SourceDir '/' Search.Name);
Application.ProcessMESSAGES;
END;
END;
REC: = FINDNEXT (SECH);
END;
FindClose (Search);
END;
20. Draw a transparent bitmap
Procedure DrawTrans (DESTCANVAS: Tcanvas; X, Y: Smallint; SrcBitmap: Tbitmap; Acolor, Backcolor: Tcolor;
Var andbitmap, Orbitmap: Tbitmap
CM: tcopymode;
SRC: TRECT; Begin
Andbitmap: = NIL;
Orbitmap: = nil;
Try
Andbitmap: = tbitmap.create;
Orbitmap: = Tbitmap.create;
SRC: = Bounds (0,0, srcbitmap.width, srcbitmap.height);
With Orbitmap Do Begin
Width: = Srcbitmap.width;
Height: = srcbitmap.Height;
Canvas.brush.color: = CLBLACK;
Canvas.copyMode: = CMSRCCPY;
Canvas.brushcopy (SRC, SrcBitmap, SRC, Acolor);
END;
With andbitmap do begin
Width: = Srcbitmap.width;
Height: = srcbitmap.Height;
Canvas.brush.color: = backcolor;
Canvas.copyMode: = CMSRCINVERT;
Canvas.brushcopy (SRC, SrcBitmap, SRC, Acolor);
END;
With Destcanvas Do Begin
CM: = COPYMODE;
CopyMode: = CMSRCAND;
Draw (X, Y, Andbitmap);
CopyMode: = CMSRCPAINT;
Draw (x, y, orbitmap);
CopyMode: = cm;
END;
Finally
Andbitmap.free;
Orbitmap.free;
END;
END;
Procedure TFORM1.BUTTON4CLICK (Sender: TOBJECT);
Begin
DrawTrans (Image1.canvas, 0, 0, Image2.Picture.bitmap, CLBLACK, CLSilver);
END;
21. Get CPU speed
Function getcpuspeed: extended;
VAR
T, MLO, NHI, NLO: DWORD;
SHR32: COMP;
Begin
SHR32: = 65536;
SHR32: = shr32 * 65536;
T: = gettickcount;
While T = GetTickCount DO;
ASM
DB 0FH, 031H // RDTSC
MOV MHI, EDX
MOV MLO, EAX
END;
While GettickCount <(t 1000) DO;
ASM
DB 0FH, 031H // RDTSC
Mov NHI, EDX
MOV NLO, EAX
END;
Result: = ((NHI * SHR32 NLO) - (MHI * SHR32 MLO) / 1E6;
END;
Procedure TFORM1.BUTTON4CLICK (Sender: TOBJECT);
Begin
Label1.caption: = floattostr (getcpuspeed) 'MHz';
END;
Temporarily just wrote so much, will gradually update the addition
