Dim idx As Integer =1
Dim t As Table = Tables("表A")
For i As Integer =t.TopPosition To t.BottomPosition Step 3
Tables("表A").rows(i)("第一列") = idx
If i+1 <= t.BottomPosition Then Tables("表A").rows(i+1)("第一列") = idx
If i+2 <= t.BottomPosition Then Tables("表A").rows(i+2)("第一列") = idx
idx+= 1
Next