If Then Else is a decision making statement based on the given condition. It first checks the condition, if the condition is true then it executes the set of statements for the true, if the condition is false the it executes the set of statements for false. It is simplest form to interrupt the flow of program.



If condition Then

Statements

Else

Statement

Using the If?Then?Else statements require the use of comparison operators to build the needed condition statements. The comparison operators compare two or more values and decide if the values are equal to each other or if one is greater than the other; then the operators return a True or False answer.

Select Case Statements

Select Case statements allow you to check for multiple values at once.

Select [Case] test condition

Case expression list

Statements

[Case Else

Statements

End Select

Example

Select Case strMonth

Case "February"

IntDays = 28

Case "April", "June", "September", "November"

IntDays = 30

Case "January", "March", "May", "July", "August", "October", "December"

IntDays = 31

End Select

Loops

You might get some situation where you want to execute some set of statements several numbers of times. To do this we have several kinds of loops in VBA. Loops can be divided in two categories (1) Iteration loops like FOR loop (2) Logical loops like WHILE loop.

Iteration Loops

Iteration loops have a fixed starting and ending point. These loops are used to repeat the execution of set of statements specific number of times.

Dim I as integer

For I = 1 to 5

Msgbox ("Counting? & I)

Next I

Logical Loops

Logical loops have no predetermined number of iterations. Instead, they rely on a logical expression that tests for a particular condition and then repeat the loop until the condition is either met or cleared, depending upon the type of loop. Based on the result of the condition logical loops executes the code.

They can be simplified into two styles: those that test the condition before performing an action and those that test the condition after performing an action.

The Do While?Loop and Do Until?Loop both test the condition before performing the action within the loop. The difference between the two is that Do While loops perform the action when the condition is true and Do Until loops perform the action while the condition is false.

Dim intCounter as Integer

IntCounter = 1

Do While IntCounter <= 10

IntCounter = intCounter + 1

Loop

Dim IntCounter as Integer

IntCounter = 1

Do Until IntCounter = 11

IntCounter = intCounter + 1

Loop

The Do?Loop While and Do?Loop Until loops are similar to each other, just as they are similar to the Do While and Do Until loops mentioned earlier. Both check the conditional expression at the end of the loop, guaranteeing at least one pass through the loop.

GoTo Statement

The GoTo statement forces the procedure to change immediately to another section of the procedure unconditionally. The section of code that is to be branched to needs to be marked with either a line number or a line label, allowing the program to jump either forward or backward within the procedure. The best use GoTo statement is in error handling, you can direct the control of program to the error handler based on the error code generated while the execution of program.

The syntax for the GoTo statement is shown here:

GoTo line

Because GoTo statements can lead to unstructured code, using them is strongly discouraged. If used sparingly, they can be very useful.