Understanding the Select Case Structure

Macros in Excel are written in a language called Visual Basic for Applications (VBA). Like any other programming language, VBA include certain programming structures which are used to control how the program executes. One of these structures is the Select Case structure. This structure has the following syntax:

Select Case expression
Case expression
    program statements
Case expression
    program statements
Case Else
    program statements
End Select

When a macro is executing, and this structure is encountered, Excel uses the expression to test each subsequent Case statement to see if the code under the Case statement should be executed. For instance, consider the following code:

Select Case DayOfWeek
Case 1
    DayName = "Monday"
Case 2
    DayName = "Tuesday"
Case 3
    DayName = "Wednesday"
Case 4
    DayName = "Thursday"
Case 5
    DayName = "Friday"
Case 6
    DayName = "Saturday"
Case 7
    DayName = "Sunday"
Case Else
    DayName = "Unknown day"
End Select

This code assumes you enter it with DayOfWeek already set to a numeric value. Let's say (for example's sake) the value is 4. In this structure, the only code that would be executed is the code under the Case 4 statement—in other words, the macro would set DayName to "Thursday." If DayOfWeek were set to some other value not accounted for by the Case statements (outside of the 1 to 7 range), then the code under Case Else would execute, and the macro would set DayName to "Unknown day."