How to display errors with ASP.NET Core

Update for beta8:
In beta8 Microsoft changed the name to UseDeveloperExceptionPage. So if you want to use the ErrorPage, call:

app.UseDeveloperExceptionPage();

Here is the link to the related Github issue.
The ErrorPageOptions are the same as in beta6/7.

---

You can use

app.UseErrorPage(ErrorPageOptions.ShowAll)

until beta5 of Asp.Net Mvc.

---

As of beta6, ErrorPageOptions.ShowAll has been removed. You can now use the version without parameters

app.UseErrorPage();

or create an ErrorPageOptions object and specify how many lines around the error you want to display by setting SourceCodeLineCount.

app.UseErrorPage(new ErrorPageOptions() {SourceCodeLineCount = 100});

---

Additional Information

They removed multiple properties of ErrorPageOptions in this commit.

Before:

public class ErrorPageOptions
{
    private bool _defaultVisibility;

    private bool? _showExceptionDetails;
    private bool? _showSourceCode;
    private bool? _showQuery;
    private bool? _showCookies;
    private bool? _showHeaders;
    private bool? _showEnvironment;
    ...
}

After:

public class ErrorPageOptions
{
    public int SourceCodeLineCount { get; set; }
    public IFileProvider FileProvider { get; set; }
    ...
}

So now you can only set how many lines of source code are printed.

Add the error page middleware as shown here:

app.UseDeveloperExceptionPage();