Reduce amount of string comparisons for handling packets

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Select Case Statement

      



Executes one of several groups ofstatements, depending on the value of anexpression.



Syntax



Select Case testexpression

[Case expressionlist-n

[statements-n]] ...

[Case Else

[elsestatements]]



End Select



The Select Case statement syntax has these parts:



Part Description 

testexpression Required. Anynumeric expression orstring expression. 

expressionlist-n Required if a Case appears. Delimited list of one or more of the following forms: expression, expression To expression, Is comparisonoperator expression. The Tokeyword specifies a range of values. If you use the To keyword, the smaller value must appear before To. Use the Is keyword withcomparison operators (except Is and Like) to specify a range of values. If not supplied, the Is keyword is automatically inserted. 

statements-n Optional. One or more statements executed if testexpression matches any part of expressionlist-n. 

elsestatements Optional. One or more statements executed if testexpression doesn't match any of the Case clause. 





Remarks



If testexpression matches any Case expressionlist expression, the statements following that Case clause are executed up to the next Case clause, or, for the last clause, up to End Select. Control then passes to the statement following End Select. If testexpression matches an expressionlist expression in more than one Case clause, only the statements following the first match are executed.



The Case Else clause is used to indicate the elsestatements to be executed if no match is found between the testexpression and an expressionlist in any of the other Case selections. Although not required, it is a good idea to have a Case Else statement in your Select Case block to handle unforeseen testexpression values. If no Case expressionlist matches testexpression and there is no Case Else statement, execution continues at the statement following End Select.



You can use multiple expressions or ranges in each Case clause. For example, the following line is valid:



Case 1 To 4, 7 To 9, 11, 13, Is > MaxNumber



Note   The Is comparison operator is not the same as the Is keyword used in the Select Case statement.



You also can specify ranges and multiple expressions for character strings. In the following example, Case matches strings that are exactly equal to everything, strings that fall between nuts and soup in alphabetic order, and the current value of TestItem:



Case "everything", "nuts" To "soup", TestItem



Select Case statements can be nested. Each nested Select Case statement must have a matching End Select statement.