VB'NET Logical Operators and Control structure

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VB.NET (Logical Operators and Control structure)

• By
• Srisawangwong,P. Asst. Prof.

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Condition expression
Comparison operators
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If statement

• If logical_expression then
• statement
• Else
• statement
• End if

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Nested If If logical_expression
then statement Elseif logical_expression
then statement else statement End if
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Compound comparison

• Logical operation
• A And B true ????????????????????
• A Or B true ????????????????????????????????????
• Not A true ????? A ????????
• A Xor B true ????????????????????????????

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Select ..Case

• Select case variable_or_expression
• Case value_1
• statement
• Case value_2
• statement
• .
• Case else
• statement
• End Select
• value_x ???????? 3 ??????
• ??????????????????/??????
• ???? Is relation ???? Case Is lt 20, Case Is 8
• ???? range value ????? ?????? to ???? Case 1 to 5

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Loop

• For Next
• For Each ltvargt In ltarray or collection namegt
• Statement
• Exit For
• Next ltvargt
• While ltconditiongt
• Statement
• Exit while
• End While
• Do
• Statement.
• Exit Do
• Loop Until ltconditiongt
• Do whileltconditiongt
• Statement..
• Exit Do
• Loop

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For loop

• Format
• For variable start_value to end_value
• statement
• Next variable
• For I1 to 10
• print I
• Next I

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Do while loop

• Do while (condition)
• body of loop
• Loop
• Do while (I lt 10)
• I I 1
• Loop

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DO Until loop

• Do
• body of loop
• Loop Until (condition)
• Do
• I I 1
• Loop Until ( I gt 10)

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Exit loop

• Normal exit
• Command exit with Exit Do and Exit For

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???????????? 4

• ?????????????????????????????????? array ???? 10
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