从EXCEL中提取数据后按序依次填写网页出现的有关问题

从EXCEL中提取数据后按序依次填写网页出现的问题
我下从EXCEL中提取数据后按序依次填写网页,出现了一些小问题,来请教下:
[code=VB][/code]Dim ex As Object
Dim wb As Object
Dim sh As Object
Private i As Integer
Private Sub Form_Load()
Set ex = CreateObject("Excel.Application")
Set wb = ex.Workbooks.Open("c:\1.xls")
Set sh = wb.Sheets(1)
WebBrowser1.Navigate "http://A.com"
i = 1
End Sub

Private Sub WebBrowser1_DocumentComplete(ByVal pDisp As Object, URL As Variant)
If WebBrowser1.LocationURL = "http://A.com" Then
If i < 21 Then
WebBrowser1.Document.Forms(0).Username.Value = sh.cells(i, 1) '类似句子不写了
esle: Set ex = Nothing
  Set wb = Nothing
  Set sh = Nothing
Unload Me
End If
End If
If WebBrowser1.LocationURL = "http://B.com" Then
WebBrowser1.GoBack
End If
End Sub[code=VB][/code]
二个问题,一是i>20后form不见了,但EXCEL进程却在增加!WHY??不能用Unload Me??
二是我本意是想其运行到sh.cells(i,1)=""时就结束程序,但若写直接在IF后写就会提示错误,变量未定义,若先用某个定义为sh.cells(i,1)他也会报错,大家说我应该怎么办?
注:引用了EXCEL和HTML object library的

------解决方案--------------------
将excel数据一次加到数组里,然后随便你用