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。
延伸阅读
文章来源于领测软件测试网 https://www.ltesting.net/
