The "You'll need a new app to open this localhost" popup message that is displayed when debugging an ASP.NET Core 2.0 application in Microsoft Edge is caused by a security feature in Edge called "HTML file association". This feature is designed to protect users from malicious HTML files that can execute harmful code on their machines.
When you start debugging an ASP.NET Core 2.0 application in Visual Studio, it launches the application in a web browser, typically Edge. When Edge receives a response from the application, it inspects the content type of the response to determine how to handle it. If the content type is not recognized by Edge, it assumes that the response is an HTML file and checks the file association for HTML files on the machine.
If the file association for HTML files is not set to Edge, or if there is no default app set for HTML files, Edge displays the "You'll need a new app to open this localhost" message to prompt the user to choose a default app to handle HTML files.
To resolve this issue, you can try the following solutions:
Set Edge as the default app for HTML files. To do this, open the Windows Settings app and go to "Apps" > "Default apps". Then, scroll down to "Web browser" and select "Microsoft Edge" from the list of available browsers.
Modify the content type of the response. If the content type of the response is not recognized by Edge, you can modify the response to include a content type that is recognized by Edge. To do this, you can set the Content-Type header of the response to "text/html" or another recognized content type.
For example, in an ASP.NET Core controller action, you can return a ContentResult with the Content and ContentType properties set:
[HttpGet]
public ContentResult Get()
{
return new ContentResult
{
Content = "<html><body><h1>Hello, World!</h1></body></html>",
ContentType = "text/html"
};
}
By trying these solutions, you should be able to resolve the "You'll need a new app to open this localhost" popup message when debugging an ASP.NET Core 2.0 application in Edge.
To determine if a .NET application is a ".NET Core" application, you can check the runtime version that the application is using. Here are a few ways to do that:
Check the Target Framework in Visual Studio: If you are using Visual Studio, you can check the Target Framework of the project. If it is set to ".NET Core", then it is a .NET Core application.
Check the Runtime Version using PowerShell: You can check the runtime version of a .NET application using PowerShell. Open PowerShell and navigate to the application directory. Then use the following command:
Get-ChildItem .\bin\Debug -Recurse -Include *.dll | %{ (Get-Item $_.FullName).VersionInfo }
This will show you the version information for all the DLLs in the bin\Debug folder. Look for the "Product Version" to determine if the application is using .NET Core.
dir /s /b *.dll | findstr /i product
This will show you the version information for all the DLLs in the application folder. Look for the "Product Version" to determine if the application is using .NET Core.
If the runtime version of the application is 3.x or higher, then it is a .NET Core application. If it is a lower version number or does not include ".NET Core" in the version number, then it is not a .NET Core application.
Migrating Identity users from an MVC5 app to an ASP.NET Core 2.2 app involves a few steps. Here is a high-level overview of the process:
Create a new ASP.NET Core 2.2 app with Identity enabled.
Export the users from the old MVC5 app using a tool like SQL Server Management Studio or a custom script.
Import the users into the new ASP.NET Core 2.2 app using the Identity API.
Here are the detailed steps:
To create a new ASP.NET Core 2.2 app with Identity enabled, follow these steps:
To export the users from the old MVC5 app, you can use a tool like SQL Server Management Studio to export the users table to a CSV file or a custom script to export the users to a JSON file. The format of the exported file should match the format of the Identity user table in the new ASP.NET Core 2.2 app.
To import the users into the new ASP.NET Core 2.2 app, you can use the Identity API to create new users based on the exported data. Here is an example of how to create a new user in ASP.NET Core 2.2:
var user = new ApplicationUser
{
UserName = "username",
Email = "[email protected]",
};
var result = await userManager.CreateAsync(user, "password");
if (result.Succeeded)
{
// User created successfully.
}
else
{
// Handle errors.
}
You will need to create a loop that iterates through the exported users and creates a new user for each one using the Identity API. You may also need to map any additional properties or claims from the old user table to the new user table.
Note that you will need to update any references to the old user IDs in your database to match the new user IDs in the ASP.NET Core 2.2 app.
Also note that you may need to handle password hashing differently between the old MVC5 app and the new ASP.NET Core 2.2 app. Make sure to use the appropriate password hashing algorithm for the new app.