输入框输入的字符，如何准确统计其个数

t1主要是输入一个有效身份证号，怎么实现判断其内容不为空 且位数是18位时，顺利显示出bb的数字位1，并递增

Dim t1 As WinForm.TextBox = e.Form.Controls("TextBox1")
Dim t2 As WinForm.TextBox = e.Form.Controls("TextBox2")
Dim tj As WinForm.Label = e.Form.Controls("个数统计")
If t1.text.Contains(",") Then
    t2.text=t1.text.ToUpper()
Else
    t2.text=t1.text.ToUpper().replace(vbcrlf, ",")
End If
Dim Multi As String = t2.text
Dim Values() As String
Values = Multi.split(",")
Dim bb As Integer=0
For Index As Integer = 0 To Values.Length - 1
    Output.Show(Values(Index))
   
    If Values(Index)<> "" And Values(Index).Length=18 Then
        bb= bb + 1
    End If
   
Next

tj.text="当前一共录入[" & bb & "]个身份证号码."    运行时永远位0

或

tj.text="当前一共录入[" & Values.Length & "]个身份证号码."    运行时会直接统计个数 但是不验证是否为空或是否18字符