用VB读取excel中的A列和B列，并相乘求和

以下是用VB读取excel中的A列和B列，并相乘求和的示例代码：

'引用Microsoft Excel Object Library
Sub MultiplyAndSum()
    Dim objExcel As New Excel.Application
    Dim objWorkbook As Excel.Workbook
    Dim objWorksheet As Excel.Worksheet
    Dim lastRow As Long
    Dim i As Long
    Dim sum As Double
    
    '打开Excel文件
    Set objWorkbook = objExcel.Workbooks.Open("C:\example.xlsx")
    Set objWorksheet = objWorkbook.Sheets(1)
    
    '获取A列和B列的最后一行
    lastRow = objWorksheet.Cells(objWorksheet.Rows.Count, "A").End(xlUp).Row
    
    '循环计算A列和B列的乘积并求和
    For i = 1 To lastRow
        sum = sum + objWorksheet.Cells(i, "A").Value * objWorksheet.Cells(i, "B").Value
    Next i
    
    '关闭Excel文件
    objWorkbook.Close SaveChanges:=False
    objExcel.Quit
    
    '输出结果
    MsgBox "A列和B列的乘积之和为：" & sum
End Sub

需要注意的是，该代码需要在引用Microsoft Excel Object Library的情况下才能运行。同时，需要将文件路径修改为实际的文件路径。