Handles clause requires a WithEvents variable defined in the containing type or one of its base type - vb.net

Question

So I'm very new to coding and especially Visual Basic, and after fidgeting around for a bit with open source code I only seem to have one recurring problem in my current Form1.vb file; Handles clause requires a WithEvents variable defined in the containing type or one of its base type. This is what is looks like:
Public Class Form1
Dim Firstnum As Decimal
Dim Secondnum As Decimal
Dim Operations As Integer
Dim Operator_selector As Boolean = False
Private lblHold As Object
Public Property TextBox1 As Object
WithEvents Btn1_click As Button
Private Sub Btn1_Click(sender As Object, e As EventArgs) Handles btn1.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "1"
Else
TextBox1.Text = "1"
End If
End Sub
Private Sub Btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "2"
Else
TextBox1.Text = "2"
End If
End Sub
Private Sub Btn3_Click(sender As Object, e As EventArgs) Handles btn3.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "3"
Else
TextBox1.Text = "3"
End If
End Sub
Private Sub Btn4_Click(sender As Object, e As EventArgs) Handles btn4.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "4"
Else
TextBox1.Text = "4"
End If
End Sub
Private Sub Btn5_Click(sender As Object, e As EventArgs) Handles btn5.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "5"
Else
TextBox1.Text = "5"
End If
End Sub
Private Sub Btn6_Click(sender As Object, e As EventArgs) Handles btn6.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "6"
Else
TextBox1.Text = "6"
End If
End Sub
Private Sub Btn7_Click(sender As Object, e As EventArgs) Handles btn7.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "7"
Else
TextBox1.Text = "7"
End If
End Sub
Private Sub Btn8_Click(sender As Object, e As EventArgs) Handles btn8.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "8"
Else
TextBox1.Text = "8"
End If
End Sub
Private Sub Btn9_Click(sender As Object, e As EventArgs) Handles btn9.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "9"
Else
TextBox1.Text = "9"
End If
End Sub
Private Sub Btn0_Click(sender As Object, e As EventArgs) Handles btn0.Click
If TextBox1.Text <> "0" Then
TextBox1.Text += "0"
End If
End Sub
Private Sub BtnPoint_Click(sender As Object, e As EventArgs) Handles btnPoint.Click
If Not (TextBox1.Text.Contains(".")) Then
TextBox1.Text += "."
End If
End Sub
Private Sub BtnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
TextBox1.Text = "0"
End Sub
Private Sub BtnPlus_Click(sender As Object, e As EventArgs) Handles btnPlus.Click
Firstnum = TextBox1.Text
TextBox1.Text = "0"
Operator_selector = True
Operations = 1 'For addition
lblHold.Text = Firstnum.ToString + "+"
End Sub
Private Sub BtnMinus_Click(sender As Object, e As EventArgs) Handles btnMinus.Click
Firstnum = TextBox1.Text
TextBox1.Text = "0"
Operator_selector = True
Operations = 2 'For subtraction
lblHold.Text = Firstnum.ToString + "-"
End Sub
Private Sub BtnMult_Click(sender As Object, e As EventArgs) Handles btnMult.Click
Firstnum = TextBox1.Text
TextBox1.Text = "0"
Operator_selector = True
Operations = 3 'For multiplication
lblHold.Text = Firstnum.ToString + "*"
End Sub
Private Sub BtnDiv_Click(sender As Object, e As EventArgs) Handles btnDiv.Click
Firstnum = TextBox1.Text
TextBox1.Text = "0"
Operator_selector = True
Operations = 4 'For division
lblHold.Text = Firstnum.ToString + "+"
End Sub
Private Sub BtnEqual_Click(sender As Object, e As EventArgs) Handles btnEqual.Click
If Operator_selector = True Then
Secondnum = TextBox1.Text
If Operations = 1 Then
TextBox1.Text = Firstnum + Secondnum
ElseIf Operations = 2 Then
TextBox1.Text = Firstnum - Secondnum
ElseIf Operations = 3 Then
TextBox1.Text = Firstnum * Secondnum
Else
If Secondnum = 0 Then
TextBox1.Text = "Error!"
Else
TextBox1.Text = Firstnum / Secondnum
End If
Operator_selector = False
End If
lblHold.Text = ""
End If
End Sub
End Class
Now I'm wondering what I have to do to get it right and make this error disappear. I tried using something around the lines of "WithEvents Btn1_click As Button" but it doesn't do anything. It also says "Btn1_click is already declared as 'Private WithEvents Btn1_click As Button' in this class." I'm truly a noob, so please don't throw hardcore coding terms at me but just the simple stuff :P
Many thanks in advance!

Answer 1

The Handles clause you see on those methods indicates that that method will be executed when the specified event of the object currently assigned to the specified variable is raised. For example:
Private Sub Btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click
means that the Btn2_Click method will be executed when the object assigned to the btn2 variable raises its Click event. The error message flags this line:
Private Sub Btn1_Click(sender As Object, e As EventArgs) Handles btn1.Click
and it's telling you that you have no btn1 variable declared WithEvents.
When you add a control to your form in the designer, it automatically adds a variable with the specified name and declares it WithEvents. You can see that variable if you open the designer code file, which you can access via the Solution Explorer if you click the Show All Files button first. You can declare your own variables WithEvents but this:
WithEvents Btn1_click As Button
is not using the correct name for a start and it is also useless because it doesn;t have anything assigned to it. You'd need to create a Button object, assign it to the variable and add it to the form, which you haven't done.
The solution would be to simply add a Button to the form with that name.