VB.Net嵌套If语句

在VB.Net中嵌套If-Then-Else语句总是合法的，这意味着可以在一个If ElseIf语句中使用另一个If或ElseIf语句。

语句

嵌套的If语句的语法如下所示：

If( boolean_expression 1)Then
   'Executes when the boolean expression 1 is true 
   If(boolean_expression 2)Then
         'Executes when the boolean expression 2 is true 
   End If
End If

示例

Module decisions
   Sub Main()
   'local variable definition '
      Dim a As Integer = 100
      Dim b As Integer = 200
      ' check the boolean condition '
      If (a = 100) Then
          ' if condition is true then check the following '
          If (b = 200) Then
              ' if condition is true then print the following '
              Console.WriteLine("Value of a is 100 and b is 200")
          End If
      End If
      Console.WriteLine("Exact value of a is : {0}", a)
      Console.WriteLine("Exact value of b is : {0}", b)
      Console.ReadLine()
   End Sub
End Module

执行上面示例代码，得到以下结果 -

Value of a is 100 and b is 200
Exact value of a is : 100
Exact value of b is : 200