ช่วยดู code ที่ผม ทำน่อยว่ามันผิด ตรงไหน asp.net

งง มาก ครับ

พอดีฝึกทำ หาข้อมูลจากในgoogle มาเสริม เติมแต่ง
กด run ได้ แต่ + - * / พอกด = อ้าวไม่ได้

ขอบคุณมา ณ โอกาศนี้ด้วยครับ

Public Class _Default
Inherits System.Web.UI.Page
Dim Operand1 As Double
Dim Operand2 As Double
Dim [Operator] As String

Private Sub cal0_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cal0.Click

IDLABLE.Text += "0"

End Sub
Protected Sub cal1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal1.Click

IDLABLE.Text += "1"

End Sub

Protected Sub cal2_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal2.Click

IDLABLE.Text += "2"

End Sub


Private Sub caldec_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles caldec.Click

IDLABLE.Text += "."
Dim i As Integer, CountDot As Integer

For i = 1 To Len(Trim$(IDLABLE.Text))
If Mid$(Trim$(IDLABLE.Text), i, 1) = "." Then CountDot = CountDot + 1
Next
If CountDot = 2 Then IDLABLE.Text = Mid$(Trim$(IDLABLE.Text), 1, Len(Trim$(IDLABLE.Text)) - 1)

End Sub


Protected Sub cal3_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal3.Click

IDLABLE.Text += "3"
End Sub

Protected Sub cal4_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal4.Click

IDLABLE.Text += "4"
End Sub

Protected Sub cal5_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal5.Click

IDLABLE.Text += "5"
End Sub

Protected Sub cal6_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal6.Click

IDLABLE.Text += "6"
End Sub

Protected Sub cal7_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal7.Click

IDLABLE.Text += "7"
End Sub

Protected Sub cal8_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal8.Click

IDLABLE.Text += "8"
End Sub

Protected Sub cal9_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cal9.Click

IDLABLE.Text += "9"
End Sub


Protected Sub calc_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calc.Click
IDLABLE.Text = ""
Operand1 = 0
Operand2 = 0

End Sub


Protected Sub calRst_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calRst.Click


Select Case [Operator]

Case "+"
IDLABLE.Text = Operand1 + Operand2


Case "-"
IDLABLE.Text = Operand1 - Operand2



Case "*"
IDLABLE.Text = Operand1 * Operand2


Case "/"
If Operand2 = 0 Then Exit Sub
IDLABLE.Text = Operand1 / Operand2

End Select

Operand2 = Val(IDLABLE.Text)

End Sub

Protected Sub calplus_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calplus.Click
IDLABLE.Text = ""
Operand1 = Operand2
Operand2 = 0
[Operator] = "+"
End Sub

Protected Sub calminus_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calminus.Click
Operand1 = Operand2
IDLABLE.Text = ""
[Operator] = "-"
End Sub

Protected Sub calmul_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calmul.Click
Operand1 = Operand2
IDLABLE.Text = ""
[Operator] = "*"
End Sub

Protected Sub caldiv_Click(ByVal sender As Object, ByVal e As EventArgs) Handles caldiv.Click
Operand1 = Operand2
IDLABLE.Text = ""
[Operator] = "/"
End Sub

Protected Sub calNegative_Click(ByVal sender As Object, ByVal e As EventArgs) Handles calNegative.Click
Operand2 = -Operand2
IDLABLE.Text = Operand2
End Sub

End Class