基本概念

在VB中的应用(1.声明 2.函数的调用)

基本概念

函数功能：该函数创建一个使用户选择逻辑字体属性的对话框，这些属性包括字体名称、字体风格（如粗体、斜体或正常体）、字号、效果（如强调线，下划线或字体颜色）和手写体（或字符集）。

函数原型：BOOL ChooseFont（LPCHOOSEFONT Ipcf）；

参数：

Ipcf：指向一个含有初始化对话框信息的CHOOSEFONT结构。当返回ChooseFont函数时，此结构含有用户对字体选择的信息。

返回值：如果用户点击对话框的OK按钮，返回值为非零值，CHOOSEFONT结构中的成员表明用户的选择。如果用户取消或关闭Font对话框或出现错误信息，返回值为零。若想获得更多错误信息。请调用CommDlgExtendedError函数，其返回值如下：

CDERR_FINDRESFAILURE；CDERR_NOHINSTANCE；CDERR_INITIALIZATION；CDERR_NOHOOK

CDERR_LOCKRESFAILURE；CDERR_NOTEMPLATE；CDERR_LOADRESFAILURE；

CDERR_STRUCTSIZE；CDERR_LOADSTRFAILURE；CDERR_MAXLESSTHANMIN

CDERR_MEMALLOCFAILURE；CDERR_NOFONTS；CDERR_MEMLOCKFAILURE

备注：可以为Font对话框提供一个CFHOOKProc挂钩程序。此挂钩程序能够处理发送给对话框的信息。

通过建立CHOOSEFONT结构中Flags成员的CE ENABLEHOOK标志和指定IPfn Hook成员中挂钩程序的地址可以使挂钩程序有效。

挂钩程序可以把信息WM_CHOOSEFONT_GETLOGLONT，WM_CHOOSEFONT_SETFLAGS和

WM_CHOOSEFONT_SETLOGFONT消息发送给对话框以便得到和创建当前值和对话框的图标。

速查：Windows NT：3.1及以一上版本；Windows：95及以上版本；Windows CE：不支持；头文件：Commdlg.h；库文件：comdlg32.lib；Unicode：在Windows NT环境中实现为Unicode和ANSI两个版本。

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CHOOSEFONT

结构体

可用于上面ChooseFont来弹出对话框选择字体,

你做出的选择如果点击ok会保存在在传递给ChooseFont的指针所指的结构体中,

所以在调用完这个函数后可以通过分析该结构题的成员获得用户选择的字体信息，

来进行相应的客户区刷新等...

在VB中的应用

1.声明

Private Const LF_FACESIZE = 32

Private Const CF_PRINTERFONTS = &H2

Private Const CF_SCREENFONTS = &H1

Private Const CF_BOTH = (CF_SCREENFONTS Or CF_PRINTERFONTS)

Private Const CF_EFFECTS = &H100&

Private Const CF_FORCEFONTEXIST = &H10000

Private Const CF_INITTOLOGFONTSTRUCT = &H40&

Private Const CF_LIMITSIZE = &H2000&

Private Const REGULAR_FONTTYPE = &H400

'charset Constants

Private Const ANSI_CHARSET = 0

Private Const ARABIC_CHARSET = 178

Private Const BALTIC_CHARSET = 186

Private Const CHINESEBIG5_CHARSET = 136

Private Const DEFAULT_CHARSET = 1

Private Const EASTEUROPE_CHARSET = 238

Private Const GB2312_CHARSET = 134

Private Const GREEK_CHARSET = 161

Private Const HANGEUL_CHARSET = 129

Private Const HEBREW_CHARSET = 177

Private Const JOHAB_CHARSET = 130

Private Const MAC_CHARSET = 77

Private Const OEM_CHARSET = 255

Private Const RUSSIAN_CHARSET = 204

Private Const SHIFTJIS_CHARSET = 128

Private Const SYMBOL_CHARSET = 2

Private Const THAI_CHARSET = 222

Private Const TURKISH_CHARSET = 162

Private Type LOGFONT

lfHeight As Long

lfWidth As Long

lfEscapement As Long

lfOrientation As Long

lfWeight As Long

lfItalic As Byte

lfUnderline As Byte

lfStrikeOut As Byte

lfCharSet As Byte

lfOutPrecision As Byte

lfClipPrecision As Byte

lfQuality As Byte

lfPitchAndFamily As Byte

lfFaceName As String * 31

End Type

Private Declare Function CHOOSEFONT Lib "comdlg32.dll" Alias "ChooseFontA" (ByRef pChoosefont As CHOOSEFONT) As Long

Private Type CHOOSEFONT

lStructSize As Long

hwndOwner As Long ' caller's window handle

hDC As Long ' printer DC/IC or NULL

lpLogFont As Long ' ptr. to a LOGFONT struct

iPointSize As Long ' 10 * size in points of selected font

flags As Long ' enum. type flags

rgbColors As Long ' returned text color

lCustData As Long ' data passed to hook fn.

lpfnHook As Long ' ptr. to hook function

lpTemplateName As String ' custom template name

hInstance As Long ' instance handle of.EXE that

' contains cust. dlg. template

lpszStyle As String ' return the style field here

' must be LF_FACESIZE or bigger

nFontType As Integer ' same value reported to the EnumFonts

' call back with the extra FONTTYPE_

' bits added

MISSING_ALIGNMENT As Integer

nSizeMin As Long ' minimum pt size allowed &

nSizeMax As Long ' max pt size allowed if

' CF_LIMITSIZE is used

End Type

2.函数的调用

假设需要改变字体的控件名称是Text1。

Dim cf As CHOOSEFONT, lfont As LOGFONT

Dim fontname As String, ret As Long

cf.flags = CF_BOTH Or CF_EFFECTS Or CF_FORCEFONTEXIST Or CF_INITTOLOGFONTSTRUCT Or CF_LIMITSIZE

cf.lpLogFont = VarPtr(lfont)

cf.lStructSize = LenB(cf)

'cf.lStructSize = Len(cf) ' size of structure

cf.hwndOwner = Form1.hWnd ' window Form1 is opening this dialog box

'cf.hDC = Printer.hDC ' device context of default printer (using VB's mechanism)

cf.rgbColors = RGB(0, 0, 0) ' black

cf.nFontType = REGULAR_FONTTYPE ' regular font type i.e. not bold or anything

cf.nSizeMin = 10 ' minimum point size

cf.nSizeMax = 72 ' maximum point size

ret = CHOOSEFONT(cf) 'brings up the font dialog

If ret <> 0 Then ' success

fontname = StrConv(lfont.lfFaceName, vbUnicode, &H804) 'Retrieve chinese font name in english version os

fontname = Left$(fontname, InStr(1, fontname, vbNullChar) - 1)

'Assign the font properties to text1

With Text1.Font

.Charset = lfont.lfCharSet 'assign charset to font

.Name = fontname

.Size = cf.iPointSize / 10 'assign point size

Text1.Text = .Name & ":" & .Charset & ":" & .Size 'display data in chosen Font

End With

End If