Visual Basic Compile Errors

I am getting lstBox is not declared and lbl1 is not declared but I named them in the form as that. Can anyone tell me how to fix this problem.

Private Sub Command1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Command1.Click

End Sub
Private Sub Command1_Click()

'input variables from user
Dim A%, B%, C%, X%, Y%
Dim num1 As Integer



A = Val(T1.Text)
B = Val(T2.Text)
C = Val(T3.Text)

If (num1 <= 0 Or num1 > 30) Then 'tests textbox 1
T1.Text = "0"
End If


If (num1 <= 0 Or num1 > 30) Then 'test textbox 2
T2.Text = "0"

End If

If (num1 <= 0 Or num1 > 30) Then 'test textbox 3
T3.Text = "0"
End If

If lstBox.ListIndex = 0 Then ' finds the sum
lbl1.Caption = A + B + C

ElseIf lstBox.ListIndex = 1 Then 'finds the product
lbl1.Caption = A * B * C

ElseIf lstBox.ListIndex = 2 Then 'finds the average
lbl1.Caption = A + B + C / 3

ElseIf lstBox.ListIndex = 3 Then ' finds smallest number

If A > B And A > C Then
X = A

ElseIf B > C Then
X = B

Else
X = C

End If
lbl1.Caption = X

ElseIf lstBox.ListIndex = 4 Then ' finds largest number

If A < B And A < C Then
Y = A

ElseIf B < C Then
Y = B
Else
Y = C
End If
lbl1.Caption = Y

End If
End Sub
End Class