ChooseFont
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。
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