[VS2008-][.Net 3.5-]A Real Beginners Guide to makeing a Simple Calculator

[spyk3]

This simple tutorial was just made to help some friends with a problem they were having in understanding basic principles of vb coding. Due to a lack of explanation, this basic calculator (presented in Ch.3 of their beginner book) was really giving them trouble. So I created one from scratch for them, that is a little bit more complicated, but only to show off many of the basics of coding in VB.
Keep in mind, this is a "Real Beginner's Guide", so any critiquing should only relate to such.

First, start a simple Vb project
On your main form (i renamed mine frmMain) place the follwing: (all can be drag and dropped from toolbox)

• Textbox named txtInput
• Label named lblResult
• RichTextbox named rtxShowWork
• 1 Button named btnClear
• 4 Buttons for Add, Subtract, Multiply, and Divide (name each as such with "btn" at beginning of the name)

After you have some fun playing with the controls and setting them to look like however you want, right click 'frmMain' in the Solution Explorer
Then select 'View Code' (NOT .designer code!)
Select all automatically created text (press Ctrl+A) and then press your 'Del' key to delete it all
Finally, start coding by following the code below, you don't need to include the comments, of course, which is every line that begins with a single quote.
However, in order for the program to work without errors, you will need every single line of actual code.
If you are a real beginner, please don't skip a step and get to know some of the easiest uses of Basic coding.

''' <summary>
''' EZ Calc Tutorial
''' JD McKinstry
''' First, it should be noted, as you become a 
''' more experienced coder, you will find this tutorial
''' to contain very simple, non-standard practices. The 
''' purpose of this is not to teach you to be company ready, 
''' it is simply to teach some very basic examples of the 
''' Basic Coding Language. Should you find this tutorial 
''' beneath your skillset, then I advise you check out MicroSoft's
''' Developer Studio online and look up the Intermidiate Tutorials.
''' </summary>
Public Class frmMain
 
    ' This is simply the establishment of a Region
    ' Regions are useful in dividing up sections of code into similar catagories
    ' This is not extremely important for now, but helps to break down the compacted view,
    ' making it easier to see all the items in your code.
#Region "   Vars/Properties     "
 
    ''' <summary>
    ''' First things first, to do simple XML Comments like this one,
    ''' Simply place cursor 1 line above the method, property, or variable
    ''' you wish to document/comment on. Then simply type 3 single quotes;
    ''' such as the ones you see at the beggining of each line here.
    ''' In Visual Studio, this will automatically create a simple XML
    ''' Document/Comment layout!
    ''' This is useful later, when looking at your Object Library, as each
    ''' section in these comments is shown in an easy to read manner.
    ''' </summary>
    ''' <remarks>Notice, it doesn't add all featues, such as the 'example' feature seen below!</remarks>
    ''' <example>ezXML_Documentation = "This is a String"</example>
    Private ezXML_Documentation As String
 
    ''' <summary>
    ''' Establish Enumerable for the 4 basic calculations.
    ''' This will later be used to determine which function 
    ''' to use as your program "calculates"
    ''' </summary>
    Enum calc
        Add
        Subtract
        Multiply
        Divide
    End Enum
 
    ''' <summary>
    ''' This is a pre-.Net 4.0 standard for establishing a 
    ''' "root variable" for later established properties.
    ''' This gives the Properties a variable to use for 
    ''' interaction.
    ''' </summary>
    Private _result As Double
    Private _calcValue As calc
 
    ''' <summary>
    ''' These are both public properties which will be
    ''' used when 'doing the work' behind this calc program.
    ''' This first property is simply used to maintain the value
    ''' of our final result for each calcullation.
    ''' </summary>
    Public Property result() As Double
        Get
            Return _result
        End Get
        Set(ByVal value As Double)
            _result = value
        End Set
    End Property
    ''' <summary>
    ''' This second property will be used to store the present
    ''' value for the function being preformed. Remember our enum?
    ''' As you notice this property is an establishment of that enum,
    ''' meaning it can hold one value selected from that enum.
    ''' </summary>
    ''' <value></value>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Property calcValue() As calc
        Get
            Return _calcValue
        End Get
        Set(ByVal value As calc)
            _calcValue = value
        End Set
    End Property
 
#End Region