Select Case structure in vb.net

Thursday, 22 December 2011 23:58

Select Case control structure is slightly different from the If....ElseIf control structure . The difference is that the Select Case control structure basically only make decision on one expression or dimension (for example the examination grade) while the If ...ElseIf statement control structure may evaluate only one expression, each If....ElseIf statement may also compute entirely different dimensions. Select Case is preferred when there exist many different conditions because using If...Then..ElseIf statements might become too messy.

The format of the Select Case control structure is show below:



Select Case expression

   Case value1

        Block of one or more VB statements

   Case value2

        Block of one or more VB Statements

   Case value3

            .

   Case Else

        Block of one or more VB Statements

End Select

Example 1



Select Case grade



      Case  "A"

           result.Caption="High  Distinction"



      Case "A-"

          result.Caption="Distinction"



      Case "B"

            result.Caption="Credit"



      Case "C"

            result.Caption="Pass"



      Case Else

            result.Caption="Fail"



  End Select

Example 2



    Select Case mark

     Case Is >= 85

         comment.Caption = "Excellence"

    Case Is >= 70

        comment.Caption = "Good"

    Case Is >= 60

       comment.Caption = "Above Average"

    Case Is >= 50

    comment.Caption = "Average"

    Case Else

    comment.Caption = "Need to work harder"

End Select

Example 3



Select Case mark

 Case 0 to 49

     comment.Caption = "Need to work harder"

Case 50 to 59

    comment.Caption = "Average"

Case 60 to 69

   comment.Caption = "Above Average"

Case 70 to 84

comment.Caption = "Good"

Case Else

comment.Caption = "Excellence"

End Select