RichEdit control Basics

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RichEdit control Basics

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· Changing the cursor position of RichEdit
· Enable trichedit to support big5 internal codes

Theory

 

A RichEdit control can be thought of as a souped-up edit control. Use Multiple font and font sizes, multi-level Undo/Redo, text search, embedded OLE objects, and drag-and-drop support for editing. The RichEdit control has many functions, so it is stored in a separate DLL file. This means that if you want to use the RichEdit control, you cannot just call the initcommoncontrols function just like using other common controls. You must first use loadlibrary to load the RichEdit DLL file.

There is a problem here, that is, the RichEdit control has a total of three versions, versions 1, 2 and 3. The following table shows the corresponding DLL file names for each version.

DLL name	RichEdit version	RichEdit Class Name
Riched32.dll	1.0	RichEdit
Richedw.dll	2.0	RICHEDIT20A
Richedw.dll	3.0	RICHEDIT20A

You will notice that versions 2 and 3 use the same DLL file name, and they also use the same class name! This will cause problems when you want to explicitly use the RichEdit 3.0 feature. So far, I have found a formal Method To differentiate versions 2.0 and. However, there is a solution that works well and I will show it to you later.

.data   RichEditDLL db "RichEd20.dll",0
.....
.data?
hRichEditDLL dd ?
.code
invoke LoadLibrary,addr RichEditDLL
mov hRichEditDLL,eax
......
invoke FreeLibrary,hRichEditDLL

When the RichEdit DLL file is loaded, it registers the RichEdit window class. Therefore, the class names of the DLL. RichEdit control must be loaded before you create the RichEdit control. Now you may have a question: how can I know which version of the RichEdit control I want to use? If you do not need any special features, the latest version may be the most appropriate. The following table lists the features provided by each RichEdit version.

Function	Release 1.0	Release 2.0	Release 3.0
Select items	X	X	X
Unicode editing		X	X
Character section format	X	X	X
Text Search	Forward search	Forward/Backward Search	Forward/Backward Search
Embedded Ole	X	X	X
Drag and Drop Edit	X	X	X
Undo/Redo	Single Stage	Multilevel	Multilevel
Automatic URL Recognition		X	X
Acceleration key support		X	X
Non-window operations		X	X
Branch character	CRLF	Cr	Cr (Yes Simulation Version 1.0)
Zoom			X
Paragraph numbering			X
Simple Table			X
Normal and heading styles			X
Underline coloring			X
Hidden text			X
Font binding			X

The above table is not comprehensive: I just listed the important functions.

Create a rchedit Control

After the DLL file is loaded, you can call createjavaswex to create the RichEdit control. when creating the control, you can use the edit control style and normal window style, except the es_lowercase, es_uppercase, and es_oemconvert style.

.constRichEditID equ 300.dataRichEditDLL db "RichEd20.dll",0
RichEditClass db "RichEdit20A",0....data?
hRichEditDLL dd ?hwndRichEdit dd ?.code.....invoke LoadLibrary,addr RichEditDLLmov hRichEditDLL,eax
invoke CreateWindowEx,0,addr RichEditClass
,WS_VISIBLE or ES_MULTILINE or WS_CHILD or WS_VSCROLL or WS_HSCROLL, /CW_USEDEFAULT,CW_USEDEFAULT
,CW_USEDEFAULT,CW_USEDEFAULT,hWnd,RichEditID,hInstance,0mov hwndRichEdit,eax

Set the default text and background color

Set text and Background The color may be a problem, but this problem has been fixed in the RichEdit control. To set the RichEdit background color, you need to send the em_setbkgndcolor message to the RichEdit control. The message has the following syntax.

Wparam = color option. If it is 0, it indicates that Windows uses the color value in lparam as the background color. If this parameter is not 0, Windows uses System Background color. Because we want to send this message to change the background color, we must set wparam to 0.
Lparam = Specify the colorref structure of the color to be set. It is valid only when wparam is 0.

For example, if I want to set the background to blue, I need to write the following code:

invoke SendMessage,hwndRichEdit,EM_SETBKGNDCOLOR,0,0FF0000h

To set the text color, the RichEdit control provides another message, which is em_setcharformat. Work The message control controls the format of a selected text or all body. The syntax of this message is as follows:

Wparam = format options:

Scf_all	This operation affects all text in the control.
Scf_selection	This operation only affects the selected text.
Scf_word or scf_selection	This operation only affects the selected word. If the selected word is empty, only the insert point (cursor) is set to the position of the specified word. The scf_word mark must be used with scf_selection.

Lparam = a pointer to the charformat or charformat2 structure, indicating the body format to be used. charformat2 is only available in RichEdit 2.0 and later. this does not mean that charformat2 must be used after RichEdit 2.0. if you do not need to use the new feature in charformat2, you can still use charformat.

CHARFORMATA STRUCT cbSize DWORD ? dwMask DWORD ? dwEffects DWORD    ? yHeight DWORD ? yOffset DWORD ? crTextColor COLORREF ? bCharSet BYTE ? bPitchAndFamily    BYTE ? szFaceName BYTE LF_FACESIZE dup(?) _wPad2 WORD ? CHARFORMATA ENDS 

Field name	Descript_ion
Cbsize	The RichEdit control uses this field to determine whether the structure version is charformat or charformat2.
Dwmask	BITs are used to specify the following members. Cfm_bold The cfe_bold value in the dweffects idiom is valid. Cfm_charset Bcharset members are valid. Cfm_color The value of cfe_autocolor in crtextcolor and dweffects is valid. Cfm_face <Font face = "Ms sans Ser