Question

在C＃中使用visual studio 2010 .NET framework 4.0。

每次尝试使用response.redirect("url")进行重定向时，都会出现以下错误：

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=App_Web_uck3gvsb
  StackTrace:
       at _Default.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\p1\Default.aspx.cs:line 15
       at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
       at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
       at System.Web.UI.Control.OnLoad(EventArgs e)
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  InnerException:

以下是代码：即使是简单的没有任何东西，我也会得到同样的错误！

using System;
using System.Collections.Generic;

using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    public  HttpResponse response;
    protected void Page_Load(object sender, EventArgs e)
    {

        response.Redirect("http://www.google.com");
    }
}

Answer 1

您应该使用：

Response.Redirect("www.bing.com");

不

response.Redirect("...")

Answer 2

您需要使用Page.Response属性：

Page.Response.Redirect(...);

或只是

Response.Redirect(...);

声明HttpResponse对象时，它未初始化，因此null。这就是例外的原因。

Answer 3

注释掉您的public HttpResponse response;您声明了一个未初始化的unnecessary变量。

public partial class _Default : System.Web.UI.Page
{
    //public  HttpResponse response;
    protected void Page_Load(object sender, EventArgs e)
    {
        //this is enough
        Response.Redirect("http://www.google.com");
    }
}

Response.Redirect（“url”）对象引用未设置为对象的实例

3 个答案: