关于VB的操作

Option Explicit

Private Sub Command1_Click()
        If IsNumeric(Text1.Text) = False Then
            MsgBox "请输入数字!"
            Exit Sub
        End If
        
        Dim i As Long
        Dim tNum As Double
        tNum = 1
        For i = 1 To CLng(Text1.Text)
            tNum = tNum * getN(i)
        Next