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基于VB的通用折行打印程序


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孔祥军 苏悦娟


 


一. 概述


几乎所有数据库应用软件,都需要打印单证和报表。常见的方法是利用VB的Crystal Reports(水晶报表)方式,通过TextBox等数据绑定控件,调用Print方法直接输出。虽然Crystal Report这一个功能强大、样式丰富且无编程方式的报表编制程序能适应大部分单证、报表打印的需要,但是Crystal Reports引擎是一个动态链接库,需许多文件支持和调用更多系统资源,大大增加系统负担。


另一种解决办法是通过Printer对象的Print方法,直接打印字符串。这虽然减少了系统资源的开销,但它不能直接用于打印复杂的单证和报表。本文通过两个实例,阐述一个通用折行打印程序的编程和在单证及报表的应用。


二. 编程实现及实例


为便于阐述的方便,我们先建立一个Access数据库Standards.mdb,其内SN表由以下几个字段组成:


标准号(文本,17)


标准名称(文本,255)


英文名称(文本,255)


实施日期(日期,8)


修定日期(日期,8)


发布日期(日期,8)


代替标准(文本,50)


通用折行打印程序编制操作如下:


1.在VB5.0编程环境中,新建一个工程Project1;


2. 在Project1中添加Moduel,在Moduel模块中定义一个记录最大折行数的公用变量Rowlab和Function函数(以下程序都经过实际运行测试,可以原样复制使用);


Public rowlab As Integer

'定义一个公用变量

Function prnt11(X As Integer, Y As

Integer,Font As Single, Txt As String, Val As Integer)

Dim str As String, str1 As String,

str2 As String ,i As Integer

Printer.CurrentX = X

Printer.CurrentY = Y

Printer.FontBold = False

Printer.FontSize = font

str = txt

str2 = str

i = 0

rowlab = 0

If Len(Trim(str)) = 0 Then

rowlab = 1 '待打印字符串为空的标志

Else

Do While Len(str) > 0

Printer.CurrentX = X

Printer.CurrentY = Y + rowlab * 240

rowlab = rowlab + 1

If Len(str) >= val Then

str1 = Mid(str, 1, val)

Printer.Print str1

i = i + 1

str = Mid(str2, i * val + 1)

Else

Printer.Print str

Exit Do

End If

Loop

End If

End Function



3. 在Project1中新建一个窗体Form1,窗体上添加一个Data控件Data1,一个MSFlexGrid控件MSFGrid1,7个TextBox和两个命令按钮CmdPrnt1、CmdPrnt2。设置Data控件的属性:


.. DatabaseName="Standards.mdb"

..RecordSourse="SN"

MSFGrid1属性:

.DataSource="Data1"

Text1属性:

.DataSource="Data1"

.DataField="标准号"

Text2~Text7类同。



CmdPrnt1、CmdPrnt2分别为打印单条记录和多条记录的按钮。


实例1:文字串定位折行打印在口岸联检部门中应用非常广泛。下述例子是用CmdPrnt1的Click事件代码实现了对文字串定位折行打印:


Private Sub CmdPrnt1_Click()

Dim str As String, str1 As String ,txt As String

Dim strx As Integer, stry As Integer,i As Integer

strx = 200

stry = 0

txt = Space(20) + "中国出入境检验检疫标准目录检索STEMS 2000"

Printer.FontName = "黑体"

dd = prnt11(strx, stry, 10, txt, 50)

stry = stry + rowlab * 240

Printer.Line (0, stry)-(9000, stry)

Printer.FontName = "宋体"

txt = "标准号:" + Space(2) + Trim(Text1) + Space(3) +

"发布日期:" + Trim(Text4) + Space(3) + "实施日期:"

+ Trim(Text6) + Space(3) + "修定日期:" + Trim(Text5) '+ Chr(13)

stry = stry + 240

dd = prnt11(strx, stry, 10, txt, 70)

stry = stry + rowlab * 240

txt = "代替标准:"

dd = prnt11(strx, stry, 10, txt, 10)

dd = prnt11(strx + 1000, stry, 10, Trim(Text7), 60)

stry = stry + rowlab * 240

txt = "标准名称:"

dd = prnt11(strx, stry, 10, txt, 10)

dd = prnt11(strx + 1000, stry, 10, Trim(Text4), 38)

stry = stry + rowlab * 240

txt = "英文名称:"

dd = prnt11(strx, stry, 10, txt, 10)

dd = prnt11(strx + 1000, stry, 10, Text5, 72)

Printer.EndDoc

End Sub



注: Prnt11函数原形:prnt11(X As Integer, Y As Integer, Font As Single, Txt As String, Val As Integer),其各参数含义如下:


X、Y为待打印字符串左上角起始座标;


Font为字体大小;


Txt为待打印字符串;


Val为字符串打印折行长度。


实例2:直接打印表格式窗体显示的多记录多字段,往往因某些字段的字节太多而造成纸张宽度不足。以下CmdPrnt2的Click事件中的代码,实现了对上述MSFGrid1表格记录的打印:


Private Sub CmdPrnt2_Click()

Dim fnt As Single

Dim pp As Integer

Dim stry As Integer, strx As Integer

Dim stry1 As Integer,

strx1 As Integer, linw As Integer

Dim page1 As Integer, p As Integer,

gridrow As Integer, ii As Integer

p = 0

ii = 1 'ii记录MSFGRID1表格同一记录内字段最大打印行

pp = 0 '开始页码

ss$ = "中国出入境检验检疫标准目录检索STEMS 2000" ' 表头

Static a(4) As Integer

kan = 0

a(2) = 1680

a(3) = 2800

a(4) = 5300

page1 = 46 '定义每页行数

strx = 200

strx1 = 200

stry = 1400

stry1 = 1400

linw = 240 '定义行宽

fnt = 10 '定义字体大小

For i = 2 To 4

kan = kan + a(i)

Next

gridrow = Datdatact1.Recordset.RecordCount

If gridrow = 0 Then

MsgBox "无满足条件记录打印!"

Exit Sub

End If

Printer.FontName = "黑体"

dd = prnt11(3300, 700, fnt, ss$, 26) '打印标题

dd = prnt11(500, stry - 250, fnt, "标准号", 26)

dd = prnt11(2690, stry - 250, fnt, "标准名称", 26)

dd = prnt11(6690, stry - 250, fnt, "英文名称", 26)

Printer.Line (strx - 20, stry - 30)-(10460, stry - 30)

Printer.FontName = "宋体"

For j = 1 To gridrow '打印gridrow条记录

MSFGrid1.Row = j

strx = strx1

For i = 2 To 4 '假设只打印2-3 列

MSFGrid1.Col = i

dd = prnt11(strx, stry, fnt,

MSFGrid1.Text, IIf(i = 3, 13, 55))

If ii < rowlab Then

'ii记录同一记录内字段最大打印行

ii = rowlab

End If

strx = strx + a(i)

Next

p = p + ii

rowlab = ii

ii = 1 '重新初始化

If p > page1 Then

p = 0

strx = strx1

For n = 2 To 4

strx = strx + a(n)

Next

pp = pp + 1

stry = stry + rowlab * linw

foot$ = "第" + CStr(pp) + "页"

dd = prnt11(strx / 2, stry + 3 * linw, 10, foot$, 26)

stry = stry1

Printer.NewPage

Printer.FontName = "黑体"

dd = prnt11(3300, 700, fnt, ss$, 26)

dd = prnt11(500, stry - 250, fnt, "标准号", 26)

dd = prnt11(2690, stry - 250, fnt, "标准名称", 26)

dd = prnt11(6690, stry - 250, fnt, "英文名称", 26)

Printer.Line (-20, stry - 30)-(10460, stry - 30)

'打印起始线

Printer.FontName = "宋体"

strx = strx1

Else

stry = stry + rowlab * linw

End If

Next

If p < page1 Then

For p = 0 To page1 + 1

strx = strx1

Next

End If

strx = strx1

For n = 2 To 4

strx = strx + a(n)

Next

pp = pp + 1

foot$ = "第" + CStr(pp) + "页"

dd = prnt11(strx / 2, stry + 3 * linw, 10, foot$, 26)

Printer.EndDoc

End Sub



以上程序在简体中文Windows98、VB5.0环境中调试通过。