Visual Studio 2005 generates some code for us when we create our projects.  Code generated by this tool can be found in a separate file with .Designer.vb extension.  The code we make are saved in a file with .vb extension only.  This is possible with the use of partial class.

Let’s take an example, say Form1.vb.  Code generated by Visual Studio 2005 is in Form1.Designer.vb.  Inside this file you will see your Form1 class being declared as a partial class and being inherited from System.Windows.Forms.Form.  One of it’s method is InitializeComponent() which is where all initializations and custom settings of properties of the form and the controls that you put on the form are generated.  So if you’ve set the Text property of your Form1 to something else, say My Form on the form’s Properties window, you will see this property being set inside the InitializeComponent() method.  Also if you added a button control on the form, you will also see initialization code for this button as well:

Me.Button1 = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(116, 150)
Me.Button1.Name = "Button1"
Me.Button1.Size = New System.Drawing.Size(75, 23)
Me.Button1.TabIndex = 0
Me.Button1.Text = "Button1"
Me.Button1.UseVisualStyleBackColor = True
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(292, 273)
Me.Controls.Add(Me.Button1)
Me.Name = "Form1"
Me.Text = "My Form"
Me.ResumeLayout(False)

Note that Button1 is declared outside the InitializeComponent() method but inside the Form1 class as:

Friend WithEvents Button1 As System.Windows.Forms.Button

It’s cool that we can view the generated code and this will actually help us understand more what’s involved in let’s say, creating a form and adding a button control on the form.