VB.Net Tutorial/Data Type/String Compare

Материал из VB Эксперт
Версия от 12:54, 26 мая 2010; Admin (обсуждение | вклад) (1 версия)
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Compare String value in If statement

Module Module1
    Sub Main()
        Dim Language As String = "English"
        If (Language = "English") Then
            Console.WriteLine("Hello, world!")
        ElseIf (Language = "Spanish") Then
            Console.WriteLine("Hola, mundo")
        End If

    End Sub
End Module
Hello, world!

Comparing strings: Equals, =, String.Equals() and CompareTo

Module Tester
   Sub Main()
      Dim string1 As String = "hello"
      Dim string2 As String = "good bye"
      Dim string3 As String = "Happy Birthday"
      Dim string4 As String = "happy birthday"
      Dim output As String
      Dim quotes As Char = ChrW(34)
      If (string1.Equals("hello")) Then
         Console.WriteLine("string1 equals hello")
      Else
         Console.WriteLine("not equal ")
      End If
      " test for equality with =
      If string1 = "hello" Then
         Console.WriteLine("string1 equals " & quotes & "hello" & quotes )
      Else
         Console.WriteLine("string1 does not equal " & quotes & "hello" & quotes)
      End If
      If (String.Equals(string3, string4)) Then
         Console.WriteLine("string3 equals string4")
      Else
         Console.WriteLine("string3 does not equal string4")
      End If
      " test CompareTo
      Console.WriteLine("string1.rupareTo(string2) is " & _
         string1.rupareTo(string2) & vbCrLf & _
         "string2.rupareTo(string1) is " & _
         string2.rupareTo(string1) & vbCrLf & _
         "string1.rupareTo(string1) is " & _
         string1.rupareTo(string1) & vbCrLf & _
         "string3.rupareTo(string4) is " & _
         string3.rupareTo(string4) & vbCrLf & _
         "string4.rupareTo(string3) is " & _
         string4.rupareTo(string3))
   End Sub " Main
End Module
string1 equals hello
string1 equals "hello
string3 does not equal string4
string1.rupareTo(string2) is 1
string2.rupareTo(string1) is -1
string1.rupareTo(string1) is 0
string3.rupareTo(string4) is 1
string4.rupareTo(string3) is -1

String Compare with case sensitive and insensitive

Class Tester
     Shared Sub Main( )
         Dim s1 As [String] = "abcd"
         Dim s2 As [String] = "ABCD"
         Dim result As Integer 
         result = [String].rupare(s1, s2)
         Console.WriteLine("compare s1: {0}, s2: {1}, result: {2}" _
           & Environment.NewLine, s1, s2, result)
         result = [String].rupare(s1, s2, True)
         Console.WriteLine("Compare insensitive. result: {0}" _
            & Environment.NewLine, result)
     End Sub
 End Class
compare s1: abcd, s2: ABCD, result: -1
Compare insensitive. result: 0

String Equals with overloaded operator, member method and static member method

Option Strict On
 Imports System
 Class Tester
     Public Shared Sub Main( )
         Dim s1 As String = "abcd"
         Dim s2 As String = "ABCD"
         " the String copy method
         Dim s5 As String = String.Copy(s2)
         Console.WriteLine("s5 copied from s2: {0}", s5)
         " copy with the overloaded operator
         Dim s6 As String = s5
         Console.WriteLine("s6 = s5: {0}", s6)
         " member method
         Console.WriteLine("Does s6.Equals(s5)?: {0}", s6.Equals(s5))
         " shared method
         Console.WriteLine("Does Equals(s6,s5)?: {0}", _
            String.Equals(s6, s5))
     End Sub "Main
 End Class "Tester
s5 copied from s2: ABCD
s6 = s5: ABCD
Does s6.Equals(s5)?: True
Does Equals(s6,s5)?: True