This article covers the use of the if then else statement in VB.NET.
The VB.NET if then else statement executes a block of code,
if a specified condition holds returns
True. If the condition returns
False however the statement will end, or you can choose to have another block of code executed using the
VB.NET operators are used heavily in if then else statements to create the expressions that will return either True or False, especially comparison and logical operators.
Only the If and End If keywords here are actually required. The ElseIf and Else keywords are optional and can be skipped if not required.
If (condition) Then #Statement to be executed ElseIf (condition) Then # Optional #Statement to be executed Else: # Optional #Statement to be executed End If
A short example demonstrating it’s use, in it’s simplest form without any optional statements. Remember to close the If statement using the
End If line.
Dim a as Integer = 5 Dim b as Integer = 2 If (a > b) Console.WriteLine("a greater than b") End If
"a greater than b"
The else statement triggers if the condition(s) in the
if statement were/was false. (This includes any
elif statements that may be present). In simpler words, it’s a block that runs if all else has failed.
Dim b as Integer = 2 If (a > b) Console.WriteLine("a greater than b") Else: Console.WriteLine("b is greater than a") End If
We haven’t specified a value for
a here under the assumption that the user will be inputting a value.
Else If Statement
As mentioned before we may have multiple conditions in the if else statements. Using
Else If statements we can define multiple conditions, thus multiple routes that the program flow might take.
Keep in mind however that whatever happens, only one route can be taken. Only one out of the many code blocks will be executed. This applies to all the code blocks in a Python if else statements, including
else code blocks.
Examples for the
Else If statement will be shown further into this article.
The following examples utilizes all the possible keywords and statements in the VB.NET if then else statement.
Module Module1 Sub Main() Dim x As Integer = 5 If (x > 0) Then Console.WriteLine("A is positive") ElseIf (x < 0) Then Console.WriteLine("B is positive") Else Console.WriteLine("A is zero") End If End Sub End Module
The above if else then statement has two main conditions. One that triggers if the number
x is less than 0, and the second triggers if x is greater than zero. However, there is also an
else that triggers it neither of the above conditions returned
True. In this case, if
x was equal to zero.
Using Multiple Conditions and operators
Here we’ll discuss the use of multiple conditions in if else statements. Since we need to use operators to chain together two or more conditions, we’ll be discussing the use of logical and comparision operators here too.
The following code from the user two inputs and proceeds to use them in the if else statement below. Both conditions are chained together using the
AND logical operators, which returns
True only if both conditions are return
Module Module1 Sub Main() Dim Input1 As String = Console.ReadLine() Dim Input2 As String = Console.ReadLine() If (Input1 > 0) And (Input2 > 0) Then Console.WriteLine("A is positive") Else Console.WriteLine("Both Numbers are not positive") End If Console.Read() End Sub End Module
You can also use other operators besides AND, such as OR and XOR.
This marks the end of the VB.NET if else statement article. Any suggestions or contributions for CodersLegacy are more than welcome. Any questions can be asked below in the comment section.