The listbox reads a list from a file.
(ExtractFilePath()+'');
();//added an item
(ExtractFilePath()+'');
Delete item ().
------------------------------------
Determine if a form is open
iffrmPriceInput<>nilthen....
Note: Sometimes a form is closed but not fully released, it is best to add frmPrintInput=nil; to the CLOSE event of the form's closure.
------------------------------------
Method of closing MDI sub-windows
Add the following code to the OnClose event handler of the child window
Action:=caFree;
DelphiFour ways are specified for a Form's closing behavior, which are:
caNone - prohibits Form from being closed.
caHide - Form is not closed, but hidden. The hidden Form can still be accessed by the program.
caFree - Form is closed and its occupied resources are freed.
caMinimize - the Form is minimized instead of being closed, which is the default closing behavior of MDI child windows.
------------------------------------
Operation of the system configuration file *.INI
Header to cite IniFiles
1. Declaring variables
IniFile:TiniFile;
2. Specify the path
IniFile:=(ExtractFilePath()+'');
3, read variables, note that there are types of variables readstring, readinteger .... etc.
titleBMPFile:=('TitleImage','FileName','');//('GroupName','Variable','DefaultValue')
4. Write or modify variables
('title','variable1','value');
5. Release after use
;
------------------------------------
Dynamic reading of images
(titleBMPFile);
------------------------------------
Usage of fastreport custom functions
1, first in the ordinary project form to define a good function
2. In the userfunction of the frreport control, write
ifansicomparetext('My_StrToRMB',Name)=0then
val:=My_StrToRMB((p1));
//MY_STRTORMB is the function name.
// If you define more than one function, just come up with a few more IFs.
You can call this function in the report design view.
------------------------------------
Arrays are defined like thissbh:array[0..9999999,0..1]ofstring;
------------------------------------
Usage of treeview
// Define the project ordinal number and nodes first
n:Integer;
Node:TTreeNode;
Node:=;
if(Node=nil)or(=-1)thenExit;//generally you can set the stateindex of the non-reactive column to -1
n:=;
------------------------------------
Fields[] return fields through the index, you have to choose the type of return!
FieldByName() returns the field by name, you have to choose the type of return!
FieldValues[] returns the values of fields by name, automated type!
------------------------------------
Calling external program methods
With ShellExecute, add SHELLAPI to the USES segment and use it as:
ShellExecute(handle,'open','c:/myapp/','-s','',SW_SHOWNORMAL);
The first parameter is the parent window handle;
The second parameter is the opening method (OPEN, PRINT both);
The third parameter is the full path to the execution file;
The fourth parameter is the execution file parameter;
The fifth parameter is the initial directory where the executable will start running;
The sixth parameter is the execution mode (SW_HIDE, SW_MAXIMIZE, SW_MINIMIZE, SW_HIDE, SW_HIDE, SW_MAXIMIZE, SW_MAXIMIZE, SW_MAXIMIZE, SW_MINIMIZE, SW_MAXIMIZE).
SW_RESTORE,SW_SHOW,SW_SHOWDEFAULT,SW_SHOWMAXIMIZED,SW_SHOWMINIMIZED,
SW_SHOWMINNOACTIVE,SW_SHOWNA,SW_SHOWNOACTIVATE,SW_SHOWNORMAL);
------------------------------------
Determine if a file exists
ifnotfileexists('')then...
------------------------------------
Judgement keys
ifKey=#13then//If the carriage return.
------------------------------------
abort
Close the window close;
Closure of the program:; and
Exit event exit.
------------------------------------
Detect if the software is already running
ifGetLastError=ERROR_ALREADY_EXISTSthen...
------------------------------------
Defining a function is written like this
functionIsReadOnly(b:Boolean;colors:Tcolor):Boolean;
------------------------------------
fastreport direct print
;// Initialization
('1',1,True,frAll);// print
Previews;.
------------------------------------
Look for an open browser and go to a site. ((or call a WINDOWS program)
Enter site ShellExecute(Handle,PChar('OPEN'),PChar(' /downloads/'),nil,nil,SW_SHOWMAXIMIZED);
Send mail ShellExecute(Handle,'open',PChar('mailto:'+++'?subject='), nil, nil, SW_SHOW);
------------------------------------
Open File dialog box
------------------------------------
Calling the help file
:='../../Help/';
------------------------------------
Open window
(self).ShowModal;
------------------------------------
Get the path of the currently executing program
FPath:=ExtractFilePath();
maybe
FileName:=ExtractFilePath(ParamStr(0))+'/MDB/ElectronicAddressBook.mdb';
------------------------------------
current path
getcurrentdir
------------------------------------
Determine that the current mouse is in a certain position (TAG)
caseTComponent(Sender).Tagof
0:begin
...
:=sCustomImage;
end;
1:begin
...
:=sCustomImage;
end;
2:begin
...
:=sCustomImage;
end;
------------------------------------
database connection
1, create an adoconnection control, named conn
2, create an adodataset control, named ds
Then you can connect and execute the SQL query with the following statement (in this case it's an access database with a password).
:='Provider=.4.0;DataSource='+getcurrentdir+'/data/;PersistSecurityInfo=False;jetoledb:databasepassword=80513';
:=true;
:=false;
:= 'select visitdate,visittime,visitclient,visitlocation,talkfromkhbforderby visitdatedesc';
:=true;
------------------------------------
usage
[dsEdit,dsInsert]then
;
------------------------------------
Difference between and
For storage such as insert only execSQL can be used.
------------------------------------
------------------------------------
------------------------------------
------------------------------------
Enter the cursor to move to another input box
ifkey=#13then
cmb_name.SetFocus;
------------------------------------
playback sound
playsound('c:/windows/media/',0,SND_ASYNC);
------------------------------------
Listbox listbox add item
cmb_name.(['Account Number']).
------------------------------------
Listview Usage
:=[0];
:=True;
(False);
(3)//delete the third item
:= 'dddddddd';//add an item
;
:=clGrayText;
<>nilthen。。。。。
//Add items to listview
first define
varitm:TListItem;
after that
;
itm:=;
:=5;
:=;
('aaaaa');
('ffffff');
('ffdfdfdf');
('oooo');
------------------------------------
Methods for statically calling DLLs
parameterized
procedureCreateSms(Text:Pchar);stdcall;External'';
parameterless
procedureCreateSms;stdcall;External'';
------------------------------------
The role of the OK, Cancel dialog box
('Really quit?' ,'hint',mb_okcancel)=idokthen
;//Terminate is to terminate the program.
showmessage('Please check the class you want to modify first');//This is simply showing the alert box
messagebox(,'Price input is not legal!' ,'Prompt',MB_OKorMB_ICONASTERISK).
------------------------------------
Steps for calling a form
The form's cells are referenced first, then the form is created, and finally displayed.
Example 1:
useuxsgl;
(TFmXsgl,FmXsgl);
;
Example 2:
Frm_LendDetail:=TFrm_LendDetail.Create(self);
Try
Frm_LendDetail.ShowModal;
Finally
Frm_LendDetail.Free;
End;
------------------------------------
Database Queries
First create a data source, then add a TADOQUERY
;
;
('select*fromtkcborderbyckcb_kh');
;
aaa=['ckcb_kc'];//take out the value of a field of the current record
;//Next record
;// Close the query
------------------------------------
Determine that the keyboard input character -chr(13) is a carriage return
ifkey=chr(13)then
;
------------------------------------
time format
:=FormatDateTime('yyyymmddhh:nn:ss',Now);
------------------------------------
Adding table data to add
dmd is the data module tbl_zgdb is the table name
withdmd.tbl_zgdbdobegin
Append;
FieldValues['HYZH']:=Edt_HYZH.text;
FieldValues['XM']:=Edt_xm.text;
FieldValues['XB']:=Edt_xb.text;
FieldValues['dw']:=Edt_dw.text;
FieldValues['ZZMM']:=zzmm;
FieldValues['CSNY']:=trim(Edt_csny.text);
FieldValues['GZSJ']:=Edt_gzsj.text;
FieldValues['DBLB']:=dblb;
FieldValues['ZCLB']:=zclb;
FieldValues['XL']:=xl;
FieldValues['BZ']:=Edt_bz.text;
Post;
close;
end;
------------------------------------
Option values for the list box
:=[];
------------------------------------
DelphiKeyboard Key Pseudocode
Usage: ifkey=chr(VK_RETURN)then...
Constant Name Hexadecimal Value Decimal Value Corresponding Keypad
VK_LBUTTON011 Left button of mouse
VK_RBUTTON022 Right button of mouse
VK-CANCEL033Contol-break implementation
VK_MBUTTON044 Middle button of mouse (3-button mouse)
VK_BACK088Backspace key
VK_TAB099Tab key
VK_CLEAR0C12Clear key
VK_RETURN0D13Enter key
VK_SHIFT1016Shift Key
VK_CONTROL1117Ctrl Key
VK_MENU1218Alt key
VK_PAUSE1319Pause key
VK_CAPITAL1420CapsLock key
VK_ESCAPE1B27Ese key
VK_SPACE2032Spacebar key
VK_PRIOR2133PageUp Key
VK_NEXT2234PageDomw Key
VK_END2335End key
VK_HOME2436Home button
VK_LEFT2537LEFTARROW key (←)
VK_UP2638UPARROW key (↑)
VK_RIGHT2739RIGHTARROW key (→)
VK_DOWN2840DOWNARROW key (↓)
VK_Select2941Select key
VK_EXECUTE2B43EXECUTE key
VK_SNAPSHOT2C44PrintScreen key
VK_Insert2D45Ins key
VK_Delete2E46Del key
VK_HELP2F47Help Key
VK_030480 key
VK_131491 key
VK_232502 key
VK_333513 key
VK_434524 key
VK_535535 key
VK_636546 key
VK_737557 key
VK_838568 key
VK_939579 key
VK_A4165A key
VK_B4266B key
VK_C4367C key
VK_D4468D key
VK_E4569E key
VK_F4670F key
VK_G4771G key
VK_H4872H key
VK_I4973I key
VK_J4A74J key
VK_K4B75K key
VK_L4C76L key
VK_M4D77M key
VK_N4E78N key
VK_O4F79O key
VK_P5080P key
VK_Q5181Q key
VK_R5282R key
VK_S5383S key
VK_T5484T key
VK_U5585U key
VK_V5686V key
VK_W5787W key
VK_X5888X key
VK_Y5989Y key
VK_BZ5A90Z key
VK_NUMPAD06096 numeric key 0 key
VK_NUMPAD16197 numeric key 1 key
VK_NUMPAD26298 Numeric Keys 2 Keys
VK_NUMPAD36399 Numeric Keys 3 Keys
VK_NUMPAD464100 Numeric Keys 4 Keys
VK_NUMPAD565101 Numeric Keys 5 Keys
VK_NUMPAD666102 Numeric Keys 6 Keys
VK_NUMPAD767103 numeric key 7 key
VK_NUMPAD868104 Numeric Keys 8 Keys
VK_NUMPAD969105 Numeric Keys 9 Keys
VK_MULTIPLY6A106* key
VK_ADD6B107+key
VK_SEPARATOR6C108Separator key
VK_SUBTRACT6D109-key
VK_DECIMAL6E110.key
VK_DIVIDE6F111 key
VK_F170112F1 key
VK_F271113F2 key
VK_F372114F3 key
VK_F473115F4 key
VK_F574116F5 key
VK_F675117F6 key
VK_F776118F7 key
VK_F877119F8 key
VK_F978120F9 key
VK_F1079121F10 key
VK_F117A122F11 key
VK_F127B123F12 key
VK_NUMLOCK90144NumLock key
VK_SCROLL91145ScrollLock key
==================
DelphiHow do you round real numbers in?
floor and ceil are functions in mathunit, useUsesMath before using them.
trunc and round are functions in systemunit that are available by default.
floor directly to the smaller take, such as floor(-123.55)=-124, floor(123.55)=123
trunc cuts down the integer directly, e.g. trunc(-123.55)=-123,floor(123.55)=123
ceil is taken directly to the larger, e.g. ceil(-123.55)=-123, ceil(123.55)=124
round calculations are rounded, e.g. round(-123.55)=-124, round(123.55)=124
==================================================
How to convert RGB colors toDelphiTcolor?
:=rgbtocolor(255,0,0);
Function.
---------
functionRGBToColor(R,G,B:Byte):TColor;
begin
Result:=BShl16or
GShl8or
R;
end;
===========================
CallbackRoutine Explanation
MyWindowClassInfo=packedrecord
Style:UINT
...
lpFnWndProc:Pointer
...
end;
The application program only needs to specify a function that can handle the message address to MyWindowClassInfo in the lpFnWndProc field, the execution environment will know the message needs to call the function, so the application program can be any function address specified to the field to represent the function that can handle the window message, this function is called by the execution environment, so this kind of function is called by the execution environment, so this function is also known as callback function (CallbackRoutine).
The mechanism of the callback function: the caller in the initialization of an object, some parameters will be passed to the object, at the same time will be a caller can access the address of the function passed to the object, this function is the caller and the callee of a notification agreement between the caller and the callee, when the agreed upon event occurs, the callee will be in accordance with the address of the callback function to invoke the function.
/
ObjectInspector (object inspector)
The Properties page displays information about the properties of the currently selected part of the form.
The Events page lists the events that the current widget can respond to
(Tip: The ObjectInspector is always visible. You can set it to StayOnTop by moving your mouse over the ObjectInspector and right-clicking to launch the ObjectInspector's pop-up menu.)
Adjustment and alignment of components
To accurately represent the dimensions of the widget, you can, on the ObjectInspector, change the properties Left (representing the number of pixel points from the left edge of the widget to the left border of the form), Top (representing the number of pixel points from the top border of the form to the top edge of the widget), Width (the width of the widget itself), and Height (the height of the widget itself).
Align the four buttons. First, select the four buttons as a group: hold down and drag the left mouse button to the lower right, draw a rectangle around the four buttons on the form, and release the left button, a dark gray border will appear around the selected buttons. Select the Edit|Align command.
Or select the 4 buttons, after the gray border appears, right click and select position,followed by align...etc, are different ways of aligning and can be resized to the same size.
Locking components
Select the Edit|LockControls option on the main menu
Setting the form's default buttons
Change the button's Default property from False to True, i.e. make it the form's default button.
OnClick event, which is the response of the application when the button receives a left click
;
The first sentence of the program uses the Execute method to make the ColorDialog run itself.
Label (label) is usually placed next to the object, used to mark these objects, when the user uses "Alt + key letters", it will automatically select the object it points to. The way to do this is to set the FocusControl property of the Label widget, and in the Value field, choose the object name of the object it is associated with.
The Edit, MaskEdit, and Memo widgets are used to receive and display user input text.ReadOnly controls whether the object can perform Windows operations during runtime.When this value is False, the text in the box can not be copied to the clipboard.MaxLength sets the length limit of the input text. With the PasswordChar property you can display the user input text in the same way that you would display a hidden password. When a field is highlighted, a keystroke operation removes this field and replaces it with the current keyboard input. This setting provides convenience in that you do not have to first delete the original text each time; however, it may also result in accidental deletion of text. By setting the AutoSelect property to False, this substitution is eliminated.
Its EditMask property provides it with a format for filtering text. Tapping the Omit button of this property brings up the Filter Edit dialog box
Memo is the memo box which, unlike the above objects, can receive multiple lines of text input. Setting ScrollBars to ssVertical adds a vertical scroll bar to it.The Align property adjusts the alignment of this object in the window, with alNone (no alignment specified), alBottom (bottom alignment), and alClient (full-window display) to choose from; and the Alignment property determines the text in the box alignment display format.Lines attribute access to the text is stored in a TStrings object, press its omit button, you can add text to it through the dialog box, you can also use the program to operate on this attribute in order to modify or increase the purpose of the note text.
ComboBox displays the available disk drives
ListBox (ListBox) Windows opens the file operation to display the file list
(ExtractFilePath()+'');
();//added an item
(ExtractFilePath()+'');
Delete item ().
------------------------------------
Determine if a form is open
iffrmPriceInput<>nilthen....
Note: Sometimes a form is closed but not fully released, it is best to add frmPrintInput=nil; to the CLOSE event of the form's closure.
------------------------------------
Method of closing MDI sub-windows
Add the following code to the OnClose event handler of the child window
Action:=caFree;
DelphiFour ways are specified for a Form's closing behavior, which are:
caNone - prohibits Form from being closed.
caHide - Form is not closed, but hidden. The hidden Form can still be accessed by the program.
caFree - Form is closed and its occupied resources are freed.
caMinimize - the Form is minimized instead of being closed, which is the default closing behavior of MDI child windows.
------------------------------------
Operation of the system configuration file *.INI
Header to cite IniFiles
1. Declaring variables
IniFile:TiniFile;
2. Specify the path
IniFile:=(ExtractFilePath()+'');
3, read variables, note that there are types of variables readstring, readinteger .... etc.
titleBMPFile:=('TitleImage','FileName','');//('GroupName','Variable','DefaultValue')
4. Write or modify variables
('title','variable1','value');
5. Release after use
;
------------------------------------
Dynamic reading of images
(titleBMPFile);
------------------------------------
Usage of fastreport custom functions
1, first in the ordinary project form to define a good function
2. In the userfunction of the frreport control, write
ifansicomparetext('My_StrToRMB',Name)=0then
val:=My_StrToRMB((p1));
//MY_STRTORMB is the function name.
// If you define more than one function, just come up with a few more IFs.
You can call this function in the report design view.
------------------------------------
Arrays are defined like thissbh:array[0..9999999,0..1]ofstring;
------------------------------------
Usage of treeview
// Define the project ordinal number and nodes first
n:Integer;
Node:TTreeNode;
Node:=;
if(Node=nil)or(=-1)thenExit;//generally you can set the stateindex of the non-reactive column to -1
n:=;
------------------------------------
Fields[] return fields through the index, you have to choose the type of return!
FieldByName() returns the field by name, you have to choose the type of return!
FieldValues[] returns the values of fields by name, automated type!
------------------------------------
Calling external program methods
With ShellExecute, add SHELLAPI to the USES segment and use it as:
ShellExecute(handle,'open','c:/myapp/','-s','',SW_SHOWNORMAL);
The first parameter is the parent window handle;
The second parameter is the opening method (OPEN, PRINT both);
The third parameter is the full path to the execution file;
The fourth parameter is the execution file parameter;
The fifth parameter is the initial directory where the executable will start running;
The sixth parameter is the execution mode (SW_HIDE, SW_MAXIMIZE, SW_MINIMIZE, SW_HIDE, SW_HIDE, SW_MAXIMIZE, SW_MAXIMIZE, SW_MAXIMIZE, SW_MINIMIZE, SW_MAXIMIZE).
SW_RESTORE,SW_SHOW,SW_SHOWDEFAULT,SW_SHOWMAXIMIZED,SW_SHOWMINIMIZED,
SW_SHOWMINNOACTIVE,SW_SHOWNA,SW_SHOWNOACTIVATE,SW_SHOWNORMAL);
------------------------------------
Determine if a file exists
ifnotfileexists('')then...
------------------------------------
Judgement keys
ifKey=#13then//If the carriage return.
------------------------------------
abort
Close the window close;
Closure of the program:; and
Exit event exit.
------------------------------------
Detect if the software is already running
ifGetLastError=ERROR_ALREADY_EXISTSthen...
------------------------------------
Defining a function is written like this
functionIsReadOnly(b:Boolean;colors:Tcolor):Boolean;
------------------------------------
fastreport direct print
;// Initialization
('1',1,True,frAll);// print
Previews;.
------------------------------------
Look for an open browser and go to a site. ((or call a WINDOWS program)
Enter site ShellExecute(Handle,PChar('OPEN'),PChar(' /downloads/'),nil,nil,SW_SHOWMAXIMIZED);
Send mail ShellExecute(Handle,'open',PChar('mailto:'+++'?subject='), nil, nil, SW_SHOW);
------------------------------------
Open File dialog box
------------------------------------
Calling the help file
:='../../Help/';
------------------------------------
Open window
(self).ShowModal;
------------------------------------
Get the path of the currently executing program
FPath:=ExtractFilePath();
maybe
FileName:=ExtractFilePath(ParamStr(0))+'/MDB/ElectronicAddressBook.mdb';
------------------------------------
current path
getcurrentdir
------------------------------------
Determine that the current mouse is in a certain position (TAG)
caseTComponent(Sender).Tagof
0:begin
...
:=sCustomImage;
end;
1:begin
...
:=sCustomImage;
end;
2:begin
...
:=sCustomImage;
end;
------------------------------------
database connection
1, create an adoconnection control, named conn
2, create an adodataset control, named ds
Then you can connect and execute the SQL query with the following statement (in this case it's an access database with a password).
:='Provider=.4.0;DataSource='+getcurrentdir+'/data/;PersistSecurityInfo=False;jetoledb:databasepassword=80513';
:=true;
:=false;
:= 'select visitdate,visittime,visitclient,visitlocation,talkfromkhbforderby visitdatedesc';
:=true;
------------------------------------
usage
[dsEdit,dsInsert]then
;
------------------------------------
Difference between and
For storage such as insert only execSQL can be used.
------------------------------------
------------------------------------
------------------------------------
------------------------------------
Enter the cursor to move to another input box
ifkey=#13then
cmb_name.SetFocus;
------------------------------------
playback sound
playsound('c:/windows/media/',0,SND_ASYNC);
------------------------------------
Listbox listbox add item
cmb_name.(['Account Number']).
------------------------------------
Listview Usage
:=[0];
:=True;
(False);
(3)//delete the third item
:= 'dddddddd';//add an item
;
:=clGrayText;
<>nilthen。。。。。
//Add items to listview
first define
varitm:TListItem;
after that
;
itm:=;
:=5;
:=;
('aaaaa');
('ffffff');
('ffdfdfdf');
('oooo');
------------------------------------
Methods for statically calling DLLs
parameterized
procedureCreateSms(Text:Pchar);stdcall;External'';
parameterless
procedureCreateSms;stdcall;External'';
------------------------------------
The role of the OK, Cancel dialog box
('Really quit?' ,'hint',mb_okcancel)=idokthen
;//Terminate is to terminate the program.
showmessage('Please check the class you want to modify first');//This is simply showing the alert box
messagebox(,'Price input is not legal!' ,'Prompt',MB_OKorMB_ICONASTERISK).
------------------------------------
Steps for calling a form
The form's cells are referenced first, then the form is created, and finally displayed.
Example 1:
useuxsgl;
(TFmXsgl,FmXsgl);
;
Example 2:
Frm_LendDetail:=TFrm_LendDetail.Create(self);
Try
Frm_LendDetail.ShowModal;
Finally
Frm_LendDetail.Free;
End;
------------------------------------
Database Queries
First create a data source, then add a TADOQUERY
;
;
('select*fromtkcborderbyckcb_kh');
;
aaa=['ckcb_kc'];//take out the value of a field of the current record
;//Next record
;// Close the query
------------------------------------
Determine that the keyboard input character -chr(13) is a carriage return
ifkey=chr(13)then
;
------------------------------------
time format
:=FormatDateTime('yyyymmddhh:nn:ss',Now);
------------------------------------
Adding table data to add
dmd is the data module tbl_zgdb is the table name
withdmd.tbl_zgdbdobegin
Append;
FieldValues['HYZH']:=Edt_HYZH.text;
FieldValues['XM']:=Edt_xm.text;
FieldValues['XB']:=Edt_xb.text;
FieldValues['dw']:=Edt_dw.text;
FieldValues['ZZMM']:=zzmm;
FieldValues['CSNY']:=trim(Edt_csny.text);
FieldValues['GZSJ']:=Edt_gzsj.text;
FieldValues['DBLB']:=dblb;
FieldValues['ZCLB']:=zclb;
FieldValues['XL']:=xl;
FieldValues['BZ']:=Edt_bz.text;
Post;
close;
end;
------------------------------------
Option values for the list box
:=[];
------------------------------------
DelphiKeyboard Key Pseudocode
Usage: ifkey=chr(VK_RETURN)then...
Constant Name Hexadecimal Value Decimal Value Corresponding Keypad
VK_LBUTTON011 Left button of mouse
VK_RBUTTON022 Right button of mouse
VK-CANCEL033Contol-break implementation
VK_MBUTTON044 Middle button of mouse (3-button mouse)
VK_BACK088Backspace key
VK_TAB099Tab key
VK_CLEAR0C12Clear key
VK_RETURN0D13Enter key
VK_SHIFT1016Shift Key
VK_CONTROL1117Ctrl Key
VK_MENU1218Alt key
VK_PAUSE1319Pause key
VK_CAPITAL1420CapsLock key
VK_ESCAPE1B27Ese key
VK_SPACE2032Spacebar key
VK_PRIOR2133PageUp Key
VK_NEXT2234PageDomw Key
VK_END2335End key
VK_HOME2436Home button
VK_LEFT2537LEFTARROW key (←)
VK_UP2638UPARROW key (↑)
VK_RIGHT2739RIGHTARROW key (→)
VK_DOWN2840DOWNARROW key (↓)
VK_Select2941Select key
VK_EXECUTE2B43EXECUTE key
VK_SNAPSHOT2C44PrintScreen key
VK_Insert2D45Ins key
VK_Delete2E46Del key
VK_HELP2F47Help Key
VK_030480 key
VK_131491 key
VK_232502 key
VK_333513 key
VK_434524 key
VK_535535 key
VK_636546 key
VK_737557 key
VK_838568 key
VK_939579 key
VK_A4165A key
VK_B4266B key
VK_C4367C key
VK_D4468D key
VK_E4569E key
VK_F4670F key
VK_G4771G key
VK_H4872H key
VK_I4973I key
VK_J4A74J key
VK_K4B75K key
VK_L4C76L key
VK_M4D77M key
VK_N4E78N key
VK_O4F79O key
VK_P5080P key
VK_Q5181Q key
VK_R5282R key
VK_S5383S key
VK_T5484T key
VK_U5585U key
VK_V5686V key
VK_W5787W key
VK_X5888X key
VK_Y5989Y key
VK_BZ5A90Z key
VK_NUMPAD06096 numeric key 0 key
VK_NUMPAD16197 numeric key 1 key
VK_NUMPAD26298 Numeric Keys 2 Keys
VK_NUMPAD36399 Numeric Keys 3 Keys
VK_NUMPAD464100 Numeric Keys 4 Keys
VK_NUMPAD565101 Numeric Keys 5 Keys
VK_NUMPAD666102 Numeric Keys 6 Keys
VK_NUMPAD767103 numeric key 7 key
VK_NUMPAD868104 Numeric Keys 8 Keys
VK_NUMPAD969105 Numeric Keys 9 Keys
VK_MULTIPLY6A106* key
VK_ADD6B107+key
VK_SEPARATOR6C108Separator key
VK_SUBTRACT6D109-key
VK_DECIMAL6E110.key
VK_DIVIDE6F111 key
VK_F170112F1 key
VK_F271113F2 key
VK_F372114F3 key
VK_F473115F4 key
VK_F574116F5 key
VK_F675117F6 key
VK_F776118F7 key
VK_F877119F8 key
VK_F978120F9 key
VK_F1079121F10 key
VK_F117A122F11 key
VK_F127B123F12 key
VK_NUMLOCK90144NumLock key
VK_SCROLL91145ScrollLock key
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DelphiHow do you round real numbers in?
floor and ceil are functions in mathunit, useUsesMath before using them.
trunc and round are functions in systemunit that are available by default.
floor directly to the smaller take, such as floor(-123.55)=-124, floor(123.55)=123
trunc cuts down the integer directly, e.g. trunc(-123.55)=-123,floor(123.55)=123
ceil is taken directly to the larger, e.g. ceil(-123.55)=-123, ceil(123.55)=124
round calculations are rounded, e.g. round(-123.55)=-124, round(123.55)=124
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How to convert RGB colors toDelphiTcolor?
:=rgbtocolor(255,0,0);
Function.
---------
functionRGBToColor(R,G,B:Byte):TColor;
begin
Result:=BShl16or
GShl8or
R;
end;
===========================
CallbackRoutine Explanation
MyWindowClassInfo=packedrecord
Style:UINT
...
lpFnWndProc:Pointer
...
end;
The application program only needs to specify a function that can handle the message address to MyWindowClassInfo in the lpFnWndProc field, the execution environment will know the message needs to call the function, so the application program can be any function address specified to the field to represent the function that can handle the window message, this function is called by the execution environment, so this kind of function is called by the execution environment, so this function is also known as callback function (CallbackRoutine).
The mechanism of the callback function: the caller in the initialization of an object, some parameters will be passed to the object, at the same time will be a caller can access the address of the function passed to the object, this function is the caller and the callee of a notification agreement between the caller and the callee, when the agreed upon event occurs, the callee will be in accordance with the address of the callback function to invoke the function.
/
ObjectInspector (object inspector)
The Properties page displays information about the properties of the currently selected part of the form.
The Events page lists the events that the current widget can respond to
(Tip: The ObjectInspector is always visible. You can set it to StayOnTop by moving your mouse over the ObjectInspector and right-clicking to launch the ObjectInspector's pop-up menu.)
Adjustment and alignment of components
To accurately represent the dimensions of the widget, you can, on the ObjectInspector, change the properties Left (representing the number of pixel points from the left edge of the widget to the left border of the form), Top (representing the number of pixel points from the top border of the form to the top edge of the widget), Width (the width of the widget itself), and Height (the height of the widget itself).
Align the four buttons. First, select the four buttons as a group: hold down and drag the left mouse button to the lower right, draw a rectangle around the four buttons on the form, and release the left button, a dark gray border will appear around the selected buttons. Select the Edit|Align command.
Or select the 4 buttons, after the gray border appears, right click and select position,followed by align...etc, are different ways of aligning and can be resized to the same size.
Locking components
Select the Edit|LockControls option on the main menu
Setting the form's default buttons
Change the button's Default property from False to True, i.e. make it the form's default button.
OnClick event, which is the response of the application when the button receives a left click
;
The first sentence of the program uses the Execute method to make the ColorDialog run itself.
Label (label) is usually placed next to the object, used to mark these objects, when the user uses "Alt + key letters", it will automatically select the object it points to. The way to do this is to set the FocusControl property of the Label widget, and in the Value field, choose the object name of the object it is associated with.
The Edit, MaskEdit, and Memo widgets are used to receive and display user input text.ReadOnly controls whether the object can perform Windows operations during runtime.When this value is False, the text in the box can not be copied to the clipboard.MaxLength sets the length limit of the input text. With the PasswordChar property you can display the user input text in the same way that you would display a hidden password. When a field is highlighted, a keystroke operation removes this field and replaces it with the current keyboard input. This setting provides convenience in that you do not have to first delete the original text each time; however, it may also result in accidental deletion of text. By setting the AutoSelect property to False, this substitution is eliminated.
Its EditMask property provides it with a format for filtering text. Tapping the Omit button of this property brings up the Filter Edit dialog box
Memo is the memo box which, unlike the above objects, can receive multiple lines of text input. Setting ScrollBars to ssVertical adds a vertical scroll bar to it.The Align property adjusts the alignment of this object in the window, with alNone (no alignment specified), alBottom (bottom alignment), and alClient (full-window display) to choose from; and the Alignment property determines the text in the box alignment display format.Lines attribute access to the text is stored in a TStrings object, press its omit button, you can add text to it through the dialog box, you can also use the program to operate on this attribute in order to modify or increase the purpose of the note text.
ComboBox displays the available disk drives
ListBox (ListBox) Windows opens the file operation to display the file list