Please help me to rectify the mistake

Question

Hellooo,
I have created a colour code resistor calculator. The program consists of 4 combobox, 2 Textbox and 1 button. I have input the coding for the calculate button to count the resistance, but the Textbox which shows the resistance only displays 0 as the answer.
Another thing would be the tolerance which i have also input the coding in the second textbox doesn't show any value. I do not know if it is my coding problem or my pc problem.
I'm using Visual Basic Express 2010. 
Can anyone solve this problem ASAP since i am in a rush of completing a project.
Thank you!
Below is my coding:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub btn_calculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_calculate.Click
Dim band1 As Integer
Dim band2 As Integer
Dim band3 As Integer
Dim band4 As Integer
If ComboBox1.SelectedText = "Black" Then
band1 = 0
ElseIf ComboBox1.SelectedText = "Brown" Then
band1 = 1
ElseIf ComboBox1.SelectedText = "Red" Then
band1 = 2
ElseIf ComboBox1.SelectedText = "Orange" Then
band1 = 3
ElseIf ComboBox1.SelectedText = "Yellow" Then
band1 = 4
ElseIf ComboBox1.SelectedText = "Green" Then
band1 = 5
ElseIf ComboBox1.SelectedText = "Blue" Then
band1 = 6
ElseIf ComboBox1.SelectedText = "Violet" Then
band1 = 7
ElseIf ComboBox1.SelectedText = "Gray" Then
band1 = 8
ElseIf ComboBox1.SelectedText = "White" Then
band1 = 9
End If
If ComboBox2.SelectedText = "Black" Then
band2 = 0
ElseIf ComboBox2.SelectedText = "Brown" Then
band2 = 1
ElseIf ComboBox2.SelectedText = "Red" Then
band2 = 2
ElseIf ComboBox2.SelectedText = "Orange" Then
band2 = 3
ElseIf ComboBox2.SelectedText = "Yellow" Then
band2 = 4
ElseIf ComboBox2.SelectedText = "Green" Then
band2 = 5
ElseIf ComboBox2.SelectedText = "Blue" Then
band2 = 6
ElseIf ComboBox2.SelectedText = "Violet" Then
band2 = 7
ElseIf ComboBox2.SelectedText = "Gray" Then
band2 = 8
ElseIf ComboBox2.SelectedText = "White" Then
band2 = 9
End If
If ComboBox3.SelectedText = "Black" Then
band3 = 1
ElseIf ComboBox2.SelectedText = "Brown" Then
band3 = 10
ElseIf ComboBox2.SelectedText = "Red" Then
band3 = 100
ElseIf ComboBox2.SelectedText = "Orange" Then
band3 = 1000
ElseIf ComboBox2.SelectedText = "Yellow" Then
band3 = 10000
ElseIf ComboBox2.SelectedText = "Green" Then
band3 = 100000
ElseIf ComboBox2.SelectedText = "Blue" Then
band3 = 1000000
ElseIf ComboBox2.SelectedText = "Violet" Then
band3 = 10000000
ElseIf ComboBox2.SelectedText = "Gray" Then
band3 = 100000000
ElseIf ComboBox2.SelectedText = "White" Then
band3 = 1000000000
End If
Dim frontnum As Integer
If ComboBox4.SelectedText = "Gold" Then
band4 = "+/- 5 %"
txt_tolerance.Text = band4
ElseIf ComboBox4.SelectedText = "Silver" Then
band4 = "+/- 15% %"
txt_tolerance.Text = band4
ElseIf ComboBox4.SelectedText = "No band" Then
band4 = "+/- 20 %"
txt_tolerance.Text = band4
End If
frontnum = band1 & band2
txt_resistance.Text = frontnum * band3
End Sub
End Class

Answer 1

I don't know why, but this seems like a great place to use an enum... Maybe you can somehow reduce code?
Public Enum Band1 As Byte
Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Violet = 7
Gray = 8
White = 9
End Enum
Public Enum Band2 As Byte
Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Violet = 7
Gray = 8
White = 9
End Enum
Public Enum Band3 As Integer
Black = 1
Brown = 10
Red = 100
Orange = 1000
Yellow = 10000
Green = 100000
Blue = 1000000
Violet = 10000000
Gray = 100000000
White = 1000000000
End Enum
Public Enum Band4 As Byte
Gold = 5
Silver = 15
NoBand = 20
End Enum
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