C# 如何避免“无法在页面回调中调用 Response.Redirect”
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How to avoid "Response.Redirect cannot be called in a Page callback"
提问by Allen Rice
I'm cleaning up some legacy framework code and a huge amount of it is simply coding by exception. No values are checked to see if they are null, and as a result, copious amounts of exceptions are thrown and caught.
我正在清理一些遗留框架代码，其中大量代码只是按异常编码。不检查任何值以查看它们是否为空，因此会抛出和捕获大量异常。
I've got most of them cleaned up, however, There are a few error / login / security related framework methods that are doing Response.Redirect and now that we are using ajax, we are getting ALOT of "Response.Redirect cannot be called in a Page callback."And I'd like to avoid this if at all possible.
我已经清理了其中的大部分，但是，有一些错误/登录/安全相关的框架方法正在执行 Response.Redirect，现在我们正在使用 ajax，我们得到了很多“Response.Redirect 不能被调用”在页面回调中。” 如果可能的话，我想避免这种情况。
Is there a way to programatically avoid this exception? I'm looking for something like
有没有办法以编程方式避免此异常？我正在寻找类似的东西
if (Request.CanRedirect)
Request.Redirect("url");
Note, this is also happening with Server.Transfer, so I'd like to be able to check if I am able to do Request.Redirect OR Server.Transfer.
请注意，Server.Transfer 也会发生这种情况，因此我希望能够检查我是否能够执行 Request.Redirect OR Server.Transfer。
Currently, its simply doing this
目前，它只是这样做
try
{
Server.Transfer("~/Error.aspx"); // sometimes response.redirect
}
catch (Exception abc)
{
// handle error here, the error is typically:
// Response.Redirect cannot be called in a Page callback
}
采纳答案by Brandon
You can try
你可以试试
if (!Page.IsCallback)
Request.Redirect("url");
or if you dont have a Page handy...
或者如果您手边没有页面...
try
{
if (HttpContext.Current == null)
return;
if (HttpContext.Current.CurrentHandler == null)
return;
if (!(HttpContext.Current.CurrentHandler is System.Web.UI.Page))
return;
if (((System.Web.UI.Page)HttpContext.Current.CurrentHandler).IsCallback)
return;
Server.Transfer("~/Error.aspx");
}
catch (Exception abc)
{
// handle it
}
回答by Dan Monego
You should load up your ScriptManager or ScriptManagerProxy, and then check the IsInAsyncPostBack flag. That would look something like this:
您应该加载 ScriptManager 或 ScriptManagerProxy，然后检查 IsInAsyncPostBack 标志。这看起来像这样：
ScriptManager sm = this.Page.Form.FindControl("myScriptManager") as ScriptManager;
if(!sm.IsInAsyncPostBack)
{
...
}
By doing this, you can mix async postbacks (which should fail to redirect) with normal postbacks, which I'm assuming you still want to redirect.
通过这样做，您可以将异步回发（应该无法重定向）与正常回发混合，我假设您仍然想要重定向。
回答by Fredrik Eder
I believe you can simply replace Server.Transfer()with Response.RedirectLocation()which works during callback.
我相信您可以简单地替换Server.Transfer()为Response.RedirectLocation()在回调期间有效的。
try
{
Response.RedirectLocation("~/Error.aspx"); // sometimes response.redirect
}
catch (Exception abc)
{
// handle error here, the error is typically:
// Response.Redirect cannot be called in a Page callback
}
回答by WheretheresaWill
As mentioned above, but expanded to include the .NET 4.x versionand assigning to the Response.RedirectLocationproperty when there is no Pageavailable.
如上所述，但扩展为包括.NET 4.x 版本并Response.RedirectLocation在没有Page可用时分配给属性。
try
{
HttpContext.Current.Response.Redirect("~/Error.aspx");
}
catch (ApplicationException)
{
HttpContext.Current.Response.RedirectLocation =
System.Web.VirtualPathUtility.ToAbsolute("~/Error.aspx");
}
