文章为本站乐博网( Lob.cn )成员hkkk和颠倒黑白原创,可以自由转载和传播,转载请保留本站的作者和信息来源,谢谢!如果大家对.Net编程开发或者关于“VB.Net获取顶级域名的方法”的话题感兴趣,就一起来www.SmallBasic.cn（乐博网旗下技术社区） 或者加入.Net超级QQ群 40797788  一起讨论，把他做得更完善吧！

感谢群成员hkkk让代码书写更规范，用他的话说是让代码更 ".net”  ^_^  

hkkk的代码书写得规范，而且设计力求严密有逻辑，多次自己调试发现不足并修正，这种编程严谨的态度值得我们学习。 

效果：

以下就是群成员hkkk提供的代码：

  Public Function FilterDomainName(ByVal Str_DomainName As String) As String
    Dim x As Integer = 0
    Dim Str_Extensions As String = ""
    Dim Arr_Ext As String()

Str_DomainName = Str_DomainName.ToLower

    Str_Extensions = "com.cn|net.cn|org.cn|gov.cn|com.hk|com|net|org|cn|hk|cc|info|biz|me|us" ' 越多级的域名请写越前面,1级域名写在最后面
    Arr_Ext = Str_Extensions.Split("|")

    For x = 0 To Arr_Ext.Length - 1
      If InStr(Str_DomainName, "." & Arr_Ext(x)) = Str_DomainName.Length - ("." & Arr_Ext(x)).Length + 1 AndAlso _
         InStr(Str_DomainName, "." & Arr_Ext(x)) <> 0 Then
        Dim Str_MyExt As String = ""
        Dim Arr_MyName As String() ''更多.net源代码和教程，来自乐博网lob.cn

        Dim chrMyExt As Char()

        Str_MyExt = Arr_Ext(x)
        Str_MyExt = "." & Str_MyExt
        chrMyExt = Str_MyExt
        Arr_MyName = Split(Str_DomainName.TrimEnd(chrMyExt), ".")
        FilterDomainName = Arr_MyName(Arr_MyName.Length - 1) & Str_MyExt

        Return FilterDomainName
      End If
    Next

    Return ""
  End Function

======================================

附上早前不够".net"的代码：（对比可以发现hkkk改良了很多）

此代码为hkkk书写风格下改进的版本：

   Function FilterDomainName(ByVal Str_DomainName As String)

        Dim x As Integer
        Dim Str_Extensions As String
        Dim Arr_Ext As Array
        Str_Extensions = "com.cn|net.cn|org.cn|gov.cn|com.hk|com|net|org|cn|hk|cc|info|biz|me|us" '  越多级的域名请写越前面,1级域名写在最后面

        Arr_Ext = Str_Extensions.Split("|")
        For x = 0 To UBound(Arr_Ext) 
            If Arr_Ext(x) = Microsoft.VisualBasic.Right(Str_DomainName.ToLower, Arr_Ext(x).Length) Then
                Dim Str_MyExt As String
                Dim Arr_MyName As Array '更多.net源代码和教程，来自乐博网lob.cn
                Str_MyExt = Arr_Ext(x)
                Arr_MyName = Split(Microsoft.VisualBasic.Left(Str_DomainName, Str_DomainName.Length - Str_MyExt.Length - 1), ".")
                FilterDomainName = Arr_MyName(Arr_MyName.Length - 1) & "." & Str_MyExt
                Exit Function
            End If
        Next
        FilterDomainName = "" '如果为空则代表输入的参数Str_DomainName并不是一个域名，确切说应该是这个域名不带我们规定的后缀名

    End Function   

群成员 Rodger 的方法如下，乐博网还没时间测试，但也先贴出来让大家参考：

abc.sina.com.cn获取sina.com.cn
asf.2342.163.com获取 163.com
 Dim a As String ="abc.sina.com.cn".ToUpper
        Dim b As String = Nothing
        a.IndexOf(".COM")
        a.IndexOf(".COM.CN")
        If a.LastIndexOf(".COM") >= 0 Then
            b = a.Substring(a.LastIndexOf(".COM"))
            a = a.Substring(0, a.LastIndexOf(".COM"))
            a = a.Substring(a.LastIndexOf(".") + 1) + b
            MsgBox(a)
        ElseIf a.LastIndexOf("COM.CN") >= 0 Then
            b = a.Substring(a.LastIndexOf(".COM.CN"))
            a = a.Substring(0, a.LastIndexOf(".COM.CN"))
            a = a.Substring(a.LastIndexOf(".") + 1) + b
            MsgBox(a)
        End If