此源代码是《asp.net揭密(第二版)》附带的光盘中的,应该是没有问题,但我用起来却真的不能用,请大家帮帮忙,看看问题处在哪里了呢?
源代码:ControlContext.vbImports System
Imports System.Web
Imports System.Web.UINamespace myControlsPublic Class ControlContext
Inherits ControlOverrides Protected Sub Render( objTextWriter As HtmlTextWriter )
Dim strHostAddress As String
Dim strUserAgent As String strHostAddress = Context.Request.UserHostAddress
strUserAgent = Context.Request.UserAgent
objTextWriter.WriteLine( "<li> HostAddress: " & strHostAddress )
objTextWriter.WriteLine( "<li> UserAgent: " & strUserAgent )
End SubEnd ClassEnd Namespace注:
1.此代码为“开发自定义控件一章”的“访问当前上下文”部分
2.当编译完此控件并拖到页面想要应用时,提示“an unhandled exception has occurred object reference not set to an instance of an object”
3.此书以asp.net1.1为平台讲解的,而我的环境是xpsp2+asp.net2.0+vs2005
源代码:ControlContext.vbImports System
Imports System.Web
Imports System.Web.UINamespace myControlsPublic Class ControlContext
Inherits ControlOverrides Protected Sub Render( objTextWriter As HtmlTextWriter )
Dim strHostAddress As String
Dim strUserAgent As String strHostAddress = Context.Request.UserHostAddress
strUserAgent = Context.Request.UserAgent
objTextWriter.WriteLine( "<li> HostAddress: " & strHostAddress )
objTextWriter.WriteLine( "<li> UserAgent: " & strUserAgent )
End SubEnd ClassEnd Namespace注:
1.此代码为“开发自定义控件一章”的“访问当前上下文”部分
2.当编译完此控件并拖到页面想要应用时,提示“an unhandled exception has occurred object reference not set to an instance of an object”
3.此书以asp.net1.1为平台讲解的,而我的环境是xpsp2+asp.net2.0+vs2005
strUserAgent = Context.Request.UserAgent
这两句改成strHostAddress = HttpContext.Current.Request.UserHostAddress
strUserAgent = HttpContext.Current.Request.UserAgent再试试
这个代码是我从光盘上复制过来的,肯定没问题
问题就出在这里
strHostAddress = Context.Request.UserHostAddress
strUserAgent = Context.Request.UserAgent
但我不知道怎么解决
.......
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end if