Add an OWIN startup class. In Visual Studio 2017 right-click the project and select Add Class. - In the Add New Item dialog box, enter OWIN in the search field, and change the name to Startup. cs, and then select Add.
NET application. As the name suggests, it is executed first when the application starts. The startup class can be configured using UseStartup<T>() method at the time of configuring the host in the Main() method of Program class as shown below. The name "Startup" is by ASP.NET Core convention.
OWIN allows web apps to be decoupled from web servers. It defines a standard way for middleware to be used in a pipeline to handle requests and associated responses. ASP.NET Core applications and middleware can interoperate with OWIN-based applications, servers, and middleware.
Create One Class With Name Startup this will help you..
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR();
}
}
In our project, we didn't need the OWIN functionality, so we removed all the owin references from the initial ASP.NET MVC template project. The problem occured after removing the OWIN startup class.
The problem was the extra owin dll's in my bin folder. When I deleted them, the problem was resolved. You should delete them by deleting the bin folder. Clean Solution does not delete these dlls.
Somehow, IIS still executes the OWIN dll's when they are in the bin folder.
On Visual Studio 2013 RC2, there is a template for this. Just add it to App_Start folder.
The template produces such a class:
using System;
using System.Threading.Tasks;
using Microsoft.Owin;
using Owin;
[assembly: OwinStartup(typeof(WebApiOsp.App_Start.Startup))]
namespace WebApiOsp.App_Start
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
// For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=316888
}
}
}
If you don't want to use the OWIN startup, this is what you should add to your web.config file:
Under AppSettings add the following line:
<add key="owin:AutomaticAppStartup" value="false" />
This is how it should look like in your web.config:
<appSettings>
<add key="owin:AutomaticAppStartup" value="false" />
</appSettings>
Have a look for the Startup.cs
file, you might be missing one of these. This file is the entry point for OWIN, so it sounds like this is missing. Take a look at OWIN Startup class
here to understand whats going on.
As your error specifies, you can disable this in the web.config by doing the following...
To disable OWIN startup discovery, add the appSetting owin:AutomaticAppStartup with a value of "false" in your web.config
First you have to create your startup file and after you must specify the locale of this file in web.config, inside appSettings tag with this line:
<add key="owin:AppStartup" value="[NameSpace].Startup"/>
It solved my problem.
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