Microsoft Visual Basic 2005 Step by Step (Step by Step (Microsoft))

Declare a variable

Type Dim followed by the variable name, the As keyword, and the variable data type in the program code. To make the variable valid in all of a form's event procedures, place this statement at the top of the code for the form, before any event procedures. For example:

Dim Country As String

Change the value of a variable

Assign a new value with the assignment operator of (=). For example:

Country = "Japan"

Get input with a dialog box

Use the InputBox function, and assign the result to a variable. For example:

UserName = InputBox("What is your name?")

Display output in a dialog box

Use the MsgBox function. (The string to be displayed in the dialog box can be stored in a variable.) For example:

Forecast = "Rain, mainly on the plain." MsgBox(Forecast, , "Spain Weather Report")

Create a constant

Type the Const keyword followed by the constant name, the assignment operator (=), the constant data type, and the fixed value. For example:

Const JackBennysAge As Short = 39

Create a formula

Link together numeric variables or values with one of the seven mathematical operators, and then assign the result to a variable or a property. For example:

Result = 1 ^ 2 * 3 \ 4 'this equals 0

Combine text strings

Use the string concatenation operator (&). For example:

Msg = "Hello" & "," & " world!"

Include a class library from the .NET Framework

Place an Imports statement at the very top of the form's code that identifies the class library. For example:

Imports System.Math

Make a call to a method from an included class library

Use the method name, and include any necessary arguments so that it can be used in a formula or a program statement. For example, to make a call to the Sqrt method in the System.Math class library:

Hypotenuse = Sqrt(x ^ 2 + y ^ 2)

Control the evaluation order in a formula

Use parentheses in the formula. For example:

Result = 1 + 2 ^ 3 \ 4 'this equals 3 Result = (1 + 2) ^ ( 3 \ 4) 'this equals 1