当我第一次使用excel的时候,就为excel的图表功能所倾倒,实在强大,并且那些图也挺漂亮了。后来我尝试着在vb里面调用excel所支持的vba功能,发现功能的确强大,就是十分繁琐。后来就考虑用vb在excel外面包一层,写成对象,去掉我们不需要的特性。这样掉用起来就方便多了,所谓一劳永逸 :p。
在这里,我将像大家介绍一个用vb编写的饼图组件,你只需要给它几个简单的参数,就可以生成一副gif格式的图片给你。调用例子如下:
dim obj
set obj = createobject("chinaaspchart.pie")
obj.addvalue "男",150
obj.addvalue "女",45
obj.addvalue "不知道",15
obj.chartname = "性别比例图"
obj.filename = "d:/123.gif"
obj.savechart
除了在vb里面可以调用,这段代码同样也可以在asp里面调用。
下面请follow me 编写我们的组件。
1.new project,请选择activex dll,在project explorer面板上选择project1,然后在属性面板上修改其name为chinaaspchart。同样把里面的class modules修改为pie
2.保存该project,将project存为chinaaspchart.vbp,将class1.cls存为pie.cls。
3.菜单project,选择菜单项references,然后请把microsoft active server pages ojbect library、microsoft excel 9.0 object library、com+ services type library选上。
注意:在nt4/win98上没有com+ service type library这个东东,应该选microsoft transaction server type library
4.编辑pie.cls,代码如下:
'-------------------------------------------------------------------------------
dim xl
dim m_chartname
dim m_chartdata()
dim m_charttype
dim m_filename
public errmsg
public founderr
dim icount
type m_value
label as string
value as double
end type
dim tvalue as m_value
public property let charttype(charttype)
m_charttype = charttype
end property
public property get charttype()
charttype = m_charttype
end property
public property let chartname(chartname)
m_chartname = chartname
end property
public property get chartname()
chartname = m_chartname
end property
public property let filename(fname)
m_filename = fname
end property
public property get filename()
filename = m_filename
end property
public sub addvalue(label,value)
icount = icount + 1
redim preserve m_chartdata(icount)
tvalue.label = label
tvalue.value = value
m_chartdata(icount) = tvalue
end sub
public sub savechart()
on error resume next
dim isheet
dim i
set xl = new excel.application
xl.application.workbooks.add
xl.workbooks(1).worksheets("sheet1").activate
if err.number <> 0 then
founderr = true
errmsg = err.description
err.clear
else
xl.workbooks(1).worksheets("sheet1").cells("2,1").value = m_chartname
for i = 1 to icount
xl.worksheets("sheet1").cells(1,i + 1).value = m_chartdata(i).label
xl.worksheets("sheet1").cells(2,i + 1).value = m_chartdata(i).value
next
xl.charts.add
xl.activechart.charttype = m_charttype
xl.activechart.setsourcedata xl.sheets("sheet1").range("a1:" & chr((icount mod 26) + asc("a")) & "2"),1
xl.activechart.location 2,"sheet1"
with xl.activechart
.hastitle = true
.charttitle.characters.text = m_chartname
end with
xl.activechart.applydatalabels 2,false,_
true,false
with xl.selection.border
.weight = 2
.linestyle = 0
end with
xl.activechart.plotarea.select
with xl.selection.border
.weight = xlhairline
.linestyle = xlnone
end with
xl.selection.interior.colorindex = xlnone
xl.activewindow.visible = false
xl.displayalerts = false
xl.activechart.export m_filename,filtername:="gif"
xl.workbooks.close
if err.number <> 0 then
founderr = true
errmsg = errmsg
err.clear
end if
end if
set xl = nothing
end sub
private sub class_initialize()
icount = 0
founderr = false
errmsg = ""
m_charttype = -4102 'xl3dpie
'54 '柱状图
end sub
'-------------------------------------------------------------------------------
5. 如果实现柱状图?
实际上前面的代码已经实现了柱状图的功能,只是缺省是饼图功能。调用代码改成如下:
dim obj
set obj = createobject("chinaaspchart.pie")
obj.addvalue "男",150
obj.addvalue "女",45
obj.addvalue "不知道",15
obj.chartname = "性别比例图"
obj.filename = "d:/123.gif"
obj.charttype=54
obj.savechart
6. 在asp里面调用该组件画图并显示它需要注意的地方。
(1)图片必须生成在web目录下。
(2)asp程序运行在多用户环境下,必须加锁处理
可以通过application实现。其逻辑如下:
if application("标志")=0 then
显示图片
else
application.lock
生成图片
显示图片
application("标志")=0
application.unlock
end if
当然何时需要生成图片置标志位,就需要您自己根据程序的要求来确定了。
总结:
com里面调用office组件是一个十分有用的技巧,它的优点是开发相对简单,使用方便,适合企业级低访问量,高业务要求的应用,缺点是占用系统资源高。
程序在windows 2000 server + office 2000 + vb6.0 上测试通过。
原帖地址:
http://topic.csdn.net/u/20100404/21/fb870a7c-9f3d-405d-adc7-b7c8b7f56600.html