我们在利用MSHFGrid读取表格数据后，有时候希望能够在末尾增加三行，读取最大值最小值平均值数据，下面介绍如何实现着一个功能。

一 准备工作

   假设SQL Server中有这样一张表格

Wincc画面上有一个MSHFGrid控件，名字叫做MSHFGrid，有一个按钮，按钮VBS脚本如下：

Sub OnClick(ByVal Item)   
Dim conn
Dim ssql
Dim ors
Dim ocom
Dim scon
Dim MSHFGrid
Dim ADODC
Dim PCName
Dim i,j,recordcount
Dim max,min,avg,sum
PCName=HMIRuntime.Tags("@LocalMachineName").Read
scon="Provider = SQLOLEDB.1;Integrated Security=SSPI;Persist SecurityInfo=False;Initial Catalog =MyDB;Data Source = " &PCName & "\WINCC"
ssql="select * from charttable"
Set conn=CreateObject("ADODB.Connection")
conn.ConnectionString=scon
conn.Cursorlocation=3
conn.open
Set ors=CreateObject("ADODB.RecordSet")
Set ocom=CreateObject("ADODB.Command")
ocom.commandtype=1
Set ocom.ActiveConnection=conn
ocom.CommandText=ssql
Set ors=ocom.Execute
Set MSHFGrid=ScreenItems("MSHFGrid")
Set MSHFGrid.DataSource=ors
MSHFGrid.Refresh
MSHFGrid.colwidth(1)=2500
Set ors=Nothing
conn.close
Set conn=Nothing
'下面的代码增加最大值最小值平均值计算
recordcount=MSHFGrid.Rows
MSHFGrid.Rows=MSHFGrid.Rows + 3
MSHFGrid.TextMatrix(recordcount,1)="最小值"
MSHFGrid.TextMatrix(recordcount + 1,1)="最大值"
MSHFGrid.TextMatrix(recordcount + 2,1)="平均值"
For j=2 To MSHFGrid.cols - 1
   max=CDbl(MSHFGrid.TextMatrix(1,j))
   min=CDbl(MSHFGrid.TextMatrix(1,j))
   sum=0.0
   MSHFGrid.colwidth(j)=1900
   For i=1 To recordcount - 1
      sum= sum + CDbl(MSHFGrid.TextMatrix(i,j))
      If max <= CDbl(MSHFGrid.TextMatrix(i,j)) Then
         max = CDbl(MSHFGrid.TextMatrix(i,j))
      End If
      If min >= CDbl(MSHFGrid.TextMatrix(i,j)) Then
         min = CDbl(MSHFGrid.TextMatrix(i,j))
      End If
   Next
   MSHFGrid.TextMatrix(recordcount,j) = min
   MSHFGrid.TextMatrix(recordcount + 1,j) = max
   avg=sum/(recordcount-1)
   MSHFGrid.TextMatrix(recordcount + 2,j) = avg
Next  
End Sub

保存后运行，就能够看到需要的效果了。需要注意的是平均值计算可能遇到除不尽的情况，小数位数较多，可以考虑转换成整数显示使用CInt()函数。