2011年計(jì)算機(jī)等級考試二級VB輔導(dǎo)實(shí)例編程(4)

　　下面的函數(shù)將返回控件能顯示的行數(shù)。

　　Function GetVisibleLines(CTextBox As TextBox) As Long

　　Dim rc As RECT

　　Dim hDC&, lfont&, oldfont&

　　Dim di&, lc&

　　Dim tm As TEXTMETRIC

　　lc = SendMessage(CTextBox.hwnd, EM_GETRECT, 0, rc)

　　lfont = SendMessage(CTextBox.hwnd, WM_GETFONT, 0, 0)

　　hDC = GetDC(CTextBox.hwnd)

　　If lfont <> 0 Then oldfont = SelectObject(hDC, lfont)

　　di = GetTextMetrics(hDC, tm)

　　If lfont <> 0 Then lfont = SelectObject(hDC, oldfont)

　　GetVisibleLines = (rc.bottom - rc.top) / tm.tmHeight

　　di = ReleaseDC(CTextBox.hwnd, hDC)

　　End Function

　　下面的函數(shù)能夠滾動(dòng)控件,不過在滾動(dòng)之前最好判斷控件的文本行數(shù)和能夠顯示的行數(shù),以免滾動(dòng)時(shí)發(fā)生混亂。函數(shù)SendMessageBynum是一個(gè)SendMessage函數(shù)的安全聲明函數(shù),其定義與SendMessage函數(shù)完全相同,只是函數(shù)名不同。

　　Function ScrollTextBox(CTextBox As TextBox, nVal As Long, Optional nVertical As Boolean = True) As Long

　　If nVertical Then

　　ScrollTextBox = SendMessageBynum(CTextBox.hwnd, EM_LINESCROLL, 0, nVal)

　　Else

　　ScrollTextBox = SendMessageBynum(CTextBox.hwnd, EM_LINESCROLL, nVal, 0)

　　End If

　　End Function

　　下面的函數(shù)能夠返回控件指定行的文本。SendMessageBystring與SendMessageBynum類似。

　　Function GetLineText(CTextBox As TextBox, LineIndex As Long) As String

　　Dim lc&, linechar&

　　linechar = SendMessageBynum(CTextBox.hwnd, EM_LINEINDEX, LineIndex, 0)

　　lc = SendMessageBynum(CTextBox.hwnd, EM_LINELENGTH, linechar, 0) + 1

　　GetLineText = String$(lc + 2, 0)

　　Mid$(GetLineText, 1, 1) = Chr(lc And &HFF)

　　Mid$(GetLineText, 2, 1) = Chr(lc \ &H100)

　　lc = SendMessageBystring(CTextBox.hwnd, EM_GETLINE, LineIndex, GetLineText)

　　GetLineText = left(GetLineText, lc)

　　End Function

　　下面的函數(shù)可以設(shè)置控件的左邊距。

　　Public Const EM_SETMARGINS& = &HD3

　　Public Const EC_LEFTMARGIN& = &H1

　　Function SetMargins(CTextBox As TextBox, nVal As Long) As Long

　　SetMargins = SendMessageBynum(CTextBox.hwnd, EM_SETMARGINS, EC_LEFTMARGIN, nVal)

　　End Function

　　2010年9月計(jì)算機(jī)等級考試成績查詢時(shí)間匯總

　　2011計(jì)算機(jī)等級考試二級VB考點(diǎn)及習(xí)題匯總

　　2011年計(jì)算機(jī)等級考試二級VB基礎(chǔ)教程匯總