ASP.NET Razor - VB Logic Conditions

Programming logic: Execute code based on conditions.

If Conditions

VB allows you to execute code based on conditions.

Useif statementto test conditions. Based on the result, the if statement returns true or false:

  • The if statement starts a code block
  • The condition is written between if and then
  • If the condition is true, the code between if ... then and end if is executed.

Example

@Code
Dim price=50
End Code
<html>
<body>
@If price>30 Then
@<p>The price is too high.</p>
End If
</body>
</html>

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Else Conditions

An if statement can containan else condition。

The else condition defines the code that is executed when the condition is false.

Example

@Code
Dim price=20
End Code
<html>
<body>
@if price>30 then
@<p>The price is too high.</p>
Else
@<p>The price is OK.</p>
End If
</body>
</htmlV>

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Note:In the example above, if the first condition is true, the code in the if block will be executed. The else condition covers "all other cases" except the if condition.

ElseIf Conditions

For multiple condition checks, you can useelseif condition：

Example

@Code
Dim price=25
End Code
<html>
<body>
@If price>=30 Then
@<p>The price is high.</p>
ElseIf price>20 And price<30
@<p>The price is OK.</p>
Else
@<p>The price is low.</p>
End If
</body>
</html>

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In the example above, if the first condition is true, the code in the if block will be executed.

If the first condition is not true and the second condition is true, the code in the elseif block will be executed.

There is no limit to the number of elseif conditions.

If neither the if nor the elseif conditions are true, the final else block (without a condition) covers "all other cases".

Select Conditions

A select blockcan be used to test individual conditions:

Example

@Code
Dim weekday=DateTime.Now.DayOfWeek
Dim day=weekday.ToString()
Dim message=""
End Code
<html>
<body>
@Select Case day
Case "Monday"
message="This is the first weekday."
Case "Thursday"
message="Only one day before weekend."
Case "Friday"
message="Tomorrow is weekend!"
Case Else
message="Today is " & day
End Select
<p>@message</p>
</body>
</html>

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"Select Case" is immediately followed by the test value (day). Each individual test condition has a case value and any number of code lines. If the test value matches the case value, the corresponding code lines are executed.

The select block has a default case (Case Else), which covers "all other cases" when none of the specified cases match.


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