How do you implement error handling in .NET Core?

In .NET Core, you can implement error handling in several ways:

1. Using try-catch blocks: This is the most basic way of handling errors in .NET Core. You can use try-catch blocks to catch exceptions that are thrown by your code.

try
{
    // Code that might throw an exception
}
catch (Exception ex)
{
    // Handle the exception
}

2. Using middleware: Middleware is a component in the ASP.NET Core pipeline that can intercept HTTP requests and responses. You can write middleware to catch exceptions and handle them.

public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate _next;

    public ErrorHandlingMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (Exception ex)
        {
            // Handle the exception
        }
    }
}

3. Using filters: Filters are components in the ASP.NET Core pipeline that can be used to implement cross-cutting concerns such as error handling. You can write an action filter to catch exceptions and handle them.

public class ErrorHandlingFilter : IActionFilter, IOrderedFilter
{
    public int Order { get; set; }

    public void OnActionExecuting(ActionExecutingContext context)
    {
    }

    public void OnActionExecuted(ActionExecutedContext context)
    {
        if (context.Exception != null)
        {
            // Handle the exception
            context.ExceptionHandled = true;
        }
    }
}


You can register the middleware or filter in the Startup.cs file:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseMiddleware<ErrorHandlingMiddleware>();

    // OR

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    }).UseFilters(filters =>
    {
        filters.Add(new ErrorHandlingFilter());
    });
}