Case

If-Then-Else, VBA statement.

Syntax
      Select Case test_expression
         Case condition_1
           result_1
         Case condition_2
           result_2
         ...
         Case condition_n
           result_n
       [ Case Else
           result_else ]
      End Select
Key
   test_expression  An expression returning a string or numeric value. 
                    This value will be compared to the list of conditions.

   condition_n      Conditions are evaluated in the order listed.
                    Once a condition is found to be true, the corresponding code
                    will be executed and no further conditions will be evaluated.

   result_n         The code to be executed when a condition is met.

Comparison operators: Less than <, Less than or equal to <=, Greater than >, Greater than or equal to >=, Not equal <>, Equal =
Range comparison can also be done: 1 To 10 or 500 To 600
or the comparison can be a comma separated list of items: 2,4,6,8,10 or "Jan", "Feb", "Mar"

Example

Dim intVoltage as Integer
Dim strDescription as String

intVoltage = Me.txtVoltage

Select Case intVoltage
   Case 110
      strDescription = "Domestic"
   Case 220,240
      strDescription = "European"
   Case 600
      strDescription = "Industrial"
   Case Else
      strDescription = "Unknown"
End Select

MsgBox strDescription

“You see things; and you say 'Why?' But I dream things that never were; and I say 'why not?'” ~ George Bernard Shaw

Related:

Nz - Detect a NULL value or Zero Length string.
If-Then-Else