ASP.NET MVC 在 HTTP 标头后无法重定向

Question

I am getting this warning in IIS can it be related to requesting cookies from the browser or how I am using Response.Redirect ? From some research I see suggestion that I need to add Response.Buffer = true; Is that correct?

Code

    public ActionResult GetTemplateById(string TemplateId)
    {    
        string loginUrl = ConfigurationManager.AppSettings["loginUrlCottTemplateId"];
        Request.Cookies.Add(new HttpCookie("ev", "sJlp+HNulad4GaX2RCjjlQ=="));
        if (Request.Cookies["customerguid"] != null)
        {
            HttpCookie cookie = Request.Cookies["customerguid"];
            string cookieValue = cookie.Value;
            cookieValue = cookieValue.Replace("%2D", "-");
        }
        else
        {
            Response.Redirect(loginUrl + TemplateId);

        }

        if (!AuthenticationRep.IsUserValid(Request))
        {
            return Redirect(storeProductLink);

        }
        var memoryStream = new System.IO.MemoryStream(fm.FileData);
        return new FileStreamResult(memoryStream, "application/pdf");
    }

IIS exception

Exception message: Cannot redirect after HTTP headers have been sent.

Thread information:
Thread ID: 213
Thread account name: IIS APPPOOL.NET v4.5
Is impersonating: False

Stack trace:

at System.Web.HttpResponse.Redirect(String url, Boolean endResponse, Boolean permanent)

Answer 1

In your ASP.NET MVC application you are redirecting using Response.Redirect(someurl) .
When used in an ASP.NET Web Forms application, any code after Response.Redirect(someurl) is never executed. However when you use the same in ASP.NET MVC the code execution will continue even after sending the redirect response. To know why, go through this .

Your code is trying to redirect two times in the same ActionResult, through -

Response.Redirect(loginUrl + TemplateId); 

and

return Redirect(storeProductLink);    

and I believe that is throwing this error.

Please change Response.Redirect(loginUrl + TemplateId) to return Redirect(loginUrl + TemplateId) and check if this fixes your problem.