Why doesn't my ASP.NET Core 7 web app launch on HTTPS?
calendar_today 20 March 2023 13:37
Up until .NET 7, when you use the
dotnet run command to run your ASP.NET Core Razor Pages (or MVC) app, the built-in Ketstrel web server would listen on two URLs, one with a
http protocol and another that uses the
https protocol. This behaviour is documented in many places (including my book) so it might come as a surprise when
you run your new .NET 7 app from the command line and it is only available on an
http binding. Something changed in .NET 7. What is it and how do you test your .NET 7 web app under
Exploring generating PDF files from HTML in ASP.NET Core
calendar_today 30 November 2022 13:45
Back in 2008, I wrote a series of articles about using iTextSharp to generate PDF files in an ASP.NET application. I still use iTextSharp in a large MVC 5 application that I'm in the process of migrating to ASP.NET Core. The version I use is very old (4.1.6), and the API is very low level so it takes quite a while to write the code required to generate even a moderately complex PDF. Ideally I need a replacement for the new application that can generate PDF files purely from HTML, which is an API I'm much more comfortable with. This ancient version of iTextSharp doesn't support HTML as a source of content. In this article, I consider some alternatives.
Incrementally Migrating an ASP.NET Framework application to Razor Pages
calendar_today 01 September 2022 07:08
Do you have a huge .NET framework application (Web forms, MVC) that relies on authentication and/or System.Web types that you would ideally like to migrate to .NET Core, but just don't have the bandwidth to put everything on hold while you rewrite the entire application on a new framework? If so, you might be interested in an exciting new project from Microsoft - SystemWebAdapters for ASP.NET Core - that enables you to incrementally migrate your old application, endpoint by endpoint.
Strongly Typed Middleware in ASP.NET Core
calendar_today 24 August 2022 12:30
Most ASP.NET Core developers are familiar with the traditional way to author
middleware classes which is based on conventions. The vast majority of examples
out there feature the convention-based approach. But
there is also a strongly typed approach available which is based on implementing
IMiddleware interface. This seems to be one of ASP.NET Core's
best kept secrets, so I thought I'd pull the curtains back and let some light
shine on it.
Using Minimal APIs in ASP.NET Core Razor Pages
calendar_today 14 December 2021 13:33
If you are using ASP.NET Core Razor Pages to develop your web application, you have already decided that the majority of your HTML will be generated on the server. Nevertheless, chances are that you will want to introduce some client side operations into the application to improve its user friendliness in places. If those operations involve data, you will probably want to work with JSON. From .NET 6, you can use a simplified minimal request handler API that works with JSON by default.
Razor Pages Startup in .NET 6
calendar_today 06 October 2021 13:05
When you create a new web app using .NET 6 (from the new RC1 templates), you might notice something is missing. There is no Startup class. What happened to it? And how do you configure your new .NET 6 web app?
I am writing a book about Razor Pages
calendar_today 26 July 2021 18:13
Just over three years go, when Razor Pages was first launched, I had a number of questions from people asking whether I was going to write a book about the Razor Pages framework. I guess they asked me because Razor Pages appeared to be a natural successor to the old ASP.NET Web Pages framework, and I had written a book about that. Also, I was regularly blogging at the time about all the good things you could do with Razor Pages. The answer then was No, primarily because I was working on my own tutorial/documentation site for Razor Pages - learnrazorpages.com.
CSS Isolation In Razor Pages
calendar_today 19 July 2021 10:54
CSS isolation was introduced in .NET 5 for Blazor components. Now it's coming to Razor Pages (and MVC views) in .NET 6, due to be released in November this year. Here's a quick look at how CSS isolation works in Razor Pages and the kind of problem that it's designed to solve.
Implementing a Custom TypeConverter In Razor Pages
calendar_today 24 November 2020 18:34
In my most recent article, I showed
how to create a custom model
binder to bind an ISO 8601 string representation of a week of the year
DateTime type in a Razor Pages application. The custom
model binder leant heavily on the existing infrastructure that binds
strings to simple types. Custom model binders are the correct solution
if you want to bind to simple types, but if you want to bind to a
complex type, the recommendation is to implement a
according to the offical docs. But the docs don't provide an example
that shows how to do that in the context of model binding. So here's
Implementing a Custom Model Binder In Razor Pages
calendar_today 10 November 2020 15:28
In Razor Pages, model binding is the process that maps data from an HTTP request to simple PageModel properties or handler parameters. Incoming data can be included in a request as posted form values, query string values or route data. The default collection of model binders cover every simple .NET data type.. But sometimes they are not enough, and you need to add your own implementation.
Working with Dates And Times in Razor Pages Forms
calendar_today 02 November 2020 17:17
When working with dates and times in a Razor Pages form, you need to render a suitable control based in the task requirement. Prior to HTML5, developers largely depended on third party date picker libraries. Now, a variety of native browser options exist, although they enjoy varied support across modern browsers. These include options for managing the date and time, just the date or time, and for working with the month or week of the year.
Display Images in Bootstrap Carousel using Razor Pages and Entity Framework
calendar_today 19 June 2020 15:37
This short article shows how to display images stored in a database in a Razor Pages application using the Bootstrap Carousel and Entity Framework Core.
Razor Pages And Bootstrap - Lazy Loading Tabs
calendar_today 10 June 2020 12:34
Tabbed interfaces are a great way for managing the presentation of large amounts of information into separate panels, where each panel's data makes sense on its own, and only one panel is viewable at a time. The tabs in a browser are a great example of this. From a Razor Pages developer's point of view, tabs are particularly useful for controlling the display of complex data in Line Of Business applications.
Razor Pages And Bootstrap - Modal Master Details
calendar_today 28 May 2020 16:09
This is the first in a series of posts exploring how to use some of the components provided by Bootstrap within a database-driven Razor Pages web application. In this article, I look at using the Bootstrap Modal in a Master/Details scenario, to display the details of the selected record in a master list.
Razor Pages Localisation - SEO-friendly URLs
calendar_today 07 January 2020 07:37
This is the fourth article in a series that explores various aspects of localisation in ASP.NET Core Razor Pages applications. This article concentrates on the SEO aspects of localisation as they pertain to URL management, and how to utilise the RouteDataRequestCultureProvider to help you manage that.
Localising Data Annotation Attributes in Razor Pages
calendar_today 17 December 2019 07:33
This is the third article in a series that explores various aspects of localisation in ASP.NET Core Razor Pages applications. The first article looked at how to work with cultures, and the second covered the basics of using resource files for static content translations. In this article, I explain how to provide localised resources for form labels and validation error messages for PageModel properties that have Data Annotation attributes applied to them.
Using Resource Files In Razor Pages Localisation
calendar_today 10 December 2019 07:50
This is the second in a series of articles that cover localisation in ASP.NET Core Razor Pages applications. In the previous article, I looked at the basic configuration required to work with cultures which are the basic building block of localisation. I showed how to specify the cultures that the application supports, how to set the culture for the current request, and how some items, such as calendars are translated depending on the current culture. This article builds on the application which was introduced in the the last article and explores how to configure and use resources to store translated versions of static content.
Localisation in ASP.NET Core Razor Pages - Cultures
calendar_today 03 December 2019 07:50
This is the first in a series of articles that explores localisation in ASP.NET Core Razor Pages applications. This article will look at the configuration required to prepare a site for content localisation, in other words, to globalise the site. Future articles will cover the creation of localised content and how to present it.
What Happened To @Helpers In ASP.NET Core?
calendar_today 21 November 2019 13:11
When you port your Razor-based application to ASP.NET Core, whether its an
MVC application or a Web Pages application, you might notice that adding a
@functions block to your .cshtml file works as expected,
but any attempt to add a
@helpers block doesn't work at all.
Improved Remote Validation in Razor Pages
calendar_today 13 November 2019 07:51
Remote Validation is a technique that uses client side script
to validate user input on the server without posting the entire form.
Remote validation has always been possible in Razor Pages using either the
RemoteAttribute, which requires an
MVC controller to work, or by writing custom client-side script. One almost completely overlooked feature that was
included in ASP.NET Core 3.0 was the introduction of a Razor Pages-specific
validation attribute that removes this reliance on MVC controllers or custom code for remote validation.
Optional Parameters in Razor Pages Routing
calendar_today 21 August 2019 20:11
Razor Pages routing is based on attribute routing and is very powerful. Parameters provide a way of passing arbitrary data to a page via the URL. Optional parameters allow URLs to matched to routes even if no parameter value is passed. Things can get a bit complicated if you want to permit multiple optional parameters.
Using Razor Components In A Razor Page
calendar_today 05 August 2019 12:40
In my last article, I looked at some of the new things that ASP.NET Core 3.0 will introduce to Razor Pages developers. One of the features that I touched on was Razor Components. In this article, I take a more detailed look at what they are and how they can be used.
What's New In .NET Core 3.0 For Razor Pages
calendar_today 24 July 2019 19:44
Later this year, .NET Core 3.0 will be released. The main features include WPF and Windows Forms support (albeit only on the Windows operating system) and server-side Blazor. Razor Pages applications will also see some changes. I cover some of these as part of a guide to upgrading an application from 2.2 to 3.0. Then I have a quick look at some of the other new features. Note that the information in this article is based on Preview 6, and is subject to change.
AJAX Posts In Razor Pages And HTTP 400 Errors
calendar_today 15 July 2019 12:41
Every other day or so it seems, a new question is posted to one of the community forums that cover ASP.NET Core Razor Pages asking why an AJAX post doesn't appear to work, or results in an HTTP 400 error. This article explains the most common cause, and offers guidance on how to solve it.
Simple Authentication In Razor Pages Without A Database
calendar_today 08 May 2019 07:26
Sometimes, using the full ASP.NET Core Identity framework is overkill for small, one-user applications that require some form of authentication. I'm thinking about blog applications, or web-based utilities that have admin areas that only you should be allowed to reach. All you really want to do is authenticate against a user name and password stored in a config file or similar. You really don't need the ceremony of a database, EF Core, ApplicationDbContexts, SignInManagers, UserManagers etc. This article provides a step-by-step guide to implementing simple authentication using just cookies, while storing credentials securely without a database.
Using Parameter Transformers To Modify Route And Parameter Values In Razor Pages
calendar_today 29 April 2019 08:45
Available from ASP.NET Core 2.2, parameter transformers enable the centralisation of logic for modifying the value of routes and route parameters in URLs generated by the anchor tag helper or the Url helper.
Creating Custom Constraints For Razor Pages Routes
calendar_today 01 April 2019 09:16
Razor Page already includes a wide range of constraints that can be used to help disambiguate routes. It is also possible for you to create your own custom constraint and then register that with the routing system.
Rendering A Partial To A String In Razor Pages
calendar_today 19 March 2019 08:22
Partial Views or Pages are primarily used as a means of including reusable snippets of HTML within one or more Razor Pages. This walkthrough illustrates how to take advantage of the power of the Razor templating system used by partial pages to generate HTML for other purposes, such as the body of a mail message.
Global Error Handling And Logging With NLog In Razor Pages
calendar_today 12 February 2019 08:26
Exceptions in .NET represent an error condition in an executing program. Error conditions can come about as a result of a large number of causes, each represented by its own exception type. Most exceptions arise from logical errors in code, such as an attempt to work with an object that has not been instantiated (
NullRefrenceException), or to divide by zero (
DivideByZeroException). Other types of exceptions result from technical issues, which may or may not be temporary. Examples of such issues might include a database or mail server being unavailable, or insufficient file system permissions.
Including Static Resources In Razor Class Libraries In ASP.NET Core
calendar_today 17 October 2018 13:32
Razor Class libraries (RCLs) were introduced in ASP.NET Core 2.1 as a way to package and distribute UI components to be referenced and consumed within a host application. You can see them as a fully functioning part of a web application packaged as a class libray. The templated management pages for ASP.NET Identity were included as a Razor Class Library in the project template in 2.1. The Identity UI RCL includes the Razor pages, Filters, a stub EmailService class that Identity uses, and local versions of both Bootstrap 3 and 4.
Adding Sorting To Paging In ASP.NET Core Razor Pages
calendar_today 10 October 2018 08:35
This article builds on the simple paging functionality that was added to a Razor Pages application in my last article by showing how to add sorting functionality so that the user can determine the order in which results are displayed.
Simple Paging In ASP.NET Core Razor Pages
calendar_today 03 October 2018 07:49
This article attempts to demonstrate how to implement simple paging functionality in a Razor Pages application. I will explain the basics behind paging, and then use BootStrap 4 to render a variety of paging links, without resorting to Nuget packages for link generation.
Customising Routing Conventions In Razor Pages
calendar_today 26 September 2018 07:39
At its heart, the Razor Pages routing story is a simple one. It uses a convention of mapping URLs to files on disk. There are ways to customise how pages are found on an individual basis, but what if you want to change the default convention in its entirety? There is also a way to do that. And it's quite simple, as this article will demonstrate, using two real-world examples.
Using Unobtrusive Ajax In Razor Pages
calendar_today 17 September 2018 08:17
There are a few demonstrations showing how to use the jQuery Unobtrusive AJAX library in ASP.NET Core, but existing examples tend to feature MVC applications. This article looks at how to use Unobtrusive AJAX in a Razor Pages setting, where it will help to remove a lot of the boilerplate associated with making AJAX requests.
Partials and AJAX In Razor Pages
calendar_today 07 September 2018 15:57
Updating portions of a page using AJAX and partial views is a routine task in ASP.NET MVC applications. The experience is little different in ASP.NET Core Razor Pages - not much, but enough to stump some people. Here is some advice on accomplishing this task, and a preview of some additional help coming in the near future.
Areas In Razor Pages
calendar_today 03 September 2018 08:01
Support for Areas was added to Razor Pages with the release of ASP.NET Core 2.1. They have long been used in MVC applications as a way to separate logical chunks of large applications into semi-independent modules to facilitate team working etc. Here, I explore how to use areas in a Razor Pages application.
Accessing The Model From Filters In Razor Pages
calendar_today 29 August 2018 08:23
Support for filters was added to Razor Pages with the release of ASP.NET Core
2.1. Filters, for those unfamiliar with them, are components that enable the
injection of processing at certain points within the Razor Page lifecycle.
They differ from Middleware in that they provide access to the
Razor Pages offers
a number of different filter options. One
of the things that you might want to do in a filter is to obtain data from an
external resource (database, web service etc) and then use it in the
PageModel or ViewData. Here, I take a look at how you can access the model or
ViewData dictionary depending on the type of filter implementation that you choose.
Razor Pages, TypeScript and Knockout
calendar_today 16 July 2018 07:54
In this article, I look at the steps required to get TypeScript up and running in the context of a Razor Pages application. I discuss why you might want to do this, and I use Knockout for the purposes of demonstration. By the end of the article, I will have configured and used TypeScript to replicate part of the final code for the Single Page Application tutorial from learn.knockout.com.
Working With JSON in Razor Pages
calendar_today 21 May 2018 13:49
UI generation and processing within web applications is moving increasingly to the client. Data processing and storage is still undertaken on the server, with JSON being the preferred format for exchanging data between the server and the client. There are a number of ways in which you can generate JSON when working with Razor Pages. This article explores some of them.
Publishing Razor Pages Applications - Gotchas
calendar_today 22 March 2018 08:15
I have just completed an article covering publishing a Razor Pages application to IIS on my Razor Pages dedicated site: learnrazorpages.com. While writing it (and publishing revised versions of the site) I uncovered a few stumbling blocks that might catch others out. So I thought they were worth highlighting here in their own post.
ViewModels and AutoMapper in Razor Pages
calendar_today 14 February 2018 08:13
The Razor Pages PageModel class is part controller, part ViewModel. In this article, I take a look at the ViewModel part of the role that the PageModel plays, and how tools like AutoMapper can be used to reduce the amount of code you need to write when assigning values between your entity model and your ViewModel.
I'm Not Writing A Book On Razor Pages
calendar_today 19 January 2018 08:47
That's right - despite a number of questions, I am not writing a book on Razor Pages, the new page-based web development framework released as part of ASP.NET Core 2.0. But I have launched a web site for people who want to learn how to use ASP.NET Core Razor Pages.
Customising Identity in Razor Pages
calendar_today 22 September 2017 14:16
The code for managing authentication in a Razor Pages application that is provided by the standard project template is a good starting point. However, chances are that you want to customise it to fit your own application needs. This article looks at the most common customisation requirements.
Introduction to Identity in Razor Pages
calendar_today 08 September 2017 08:09
Razor Pages uses ASP.NET Identity as its default membership and authentication system. This article is the first in a series that explores the various parts of ASP.NET Identity as it relates to Razor Pages, and starts with an overview of the files generated as part of the project templates.
Sending Email in Razor Pages
calendar_today 20 July 2017 07:24
The Razor Pages framework is not the only thing to be introduced as part of .NET Core 2.0. A lot more of the existing full framework class libraries are also being ported across to .NET Core including System.Net.Mail. That means there is no longer any need to rely on third party libraries or services for email functionality in your .NET Core applications. So I thought I'd take the opportunity to illustrate sending email in a Razor Pages application.
Routing in Razor Pages
calendar_today 11 July 2017 13:28
One of the top level design considerations for the developers of a server-side web application framework is how to match URLs to resources on the server so that the correct one processes the request. The most straightforward approach is to map URLs to physical files on disk, and this is the approach that has been implemented by the ASP.NET team for the Razor Pages framework.
Razor Pages - The Elevator Pitch
calendar_today 25 May 2017 08:29
In the last ASP.NET Community Standup, Jon Galloway gave my introductory Razor Pages article a shout out (thank you, Jon). During the discussion that ensued, Scott Hanselman asked for the "elevator pitch" for Razor Pages. Well, here's mine.
Razor Pages - Understanding Handler Methods
calendar_today 22 May 2017 20:16
Handler methods is a particularly nice feature introduced with the new ASP.NET Razor Pages framework . This feature enables you to determine what the user was doing when they requested the page, and to execute logic accordingly without having to resort to a bunch of conditional code.
Razor Pages - Getting Started With The Preview
calendar_today 15 May 2017 20:52
Current users of ASP.NET Web Pages have been eagerly awaiting news on what ASP.NET Core holds for them (if my inbox is anything to go by). The roadmap suggested that a new version of Web Pages would be forthcoming after the initial release of .NET Core, but that item was subsequently removed. Instead, a new cross platform page-centric web development model called Razor Pages has been made available in preview form. Here, I show you how to get started with it and explore its similarities with Web Pages. In future articles, I will take a closer look at the wide range of differences.
ASP.NET Web Pages vNext or Razor Pages
calendar_today 15 July 2016 14:09
Now that the RTM of ASP.NET Core has shipped, the ASP.NET team are looking at the features that were left behind including SignalR and Web Pages. The ASP.NET Core road map always had those items scheduled for inclusion in the first major release after RTM, which will be ASP.NET Core 1.1. Recently, the ASP.NET Team provided an update on GitHub on the goals driving the next version of Web Pages which provides an interesting insight into the potential features of the framework.