ASP.NET Core

Uploading Files In Blazor

calendar_today 17 October 2019 07:47

ASP.NET Core Blazor

A few weeks ago, Steve Sanderson blogged about publishing a package for a prototype Blazor file input component, designed to make working with user-supplied files in Blazor applications a lot easier. Steve has provided some very clear examples demonstrating how to use the component in a number of scenarios. Missing, though, is an example showing how to make an HTTP request to upload a file to some back-end server from a Blazor WebAssembly application.

Working With Query Strings In Blazor

calendar_today 11 October 2019 12:44

ASP.NET Core Blazor

When passing data in a URL within a Blazor application, most of the time you will define route templates that incorporate parameter placeholders, passing values as URL segments. You might also find that you need to be able to work with query string values, so how do you do that in a Blazor application?

Optional Parameters in Razor Pages Routing

calendar_today 21 August 2019 20:11

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages Blazor

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

ASP.NET Core Razor Pages Blazor

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages ASP.NET Identity

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

AJAX ASP.NET Core Razor Pages

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

AJAX ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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 HttpContext. 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.

Query Types in Entity Framework Core

calendar_today 15 August 2018 13:46

Entity Framework ASP.NET Core

Query Types, introduced in Entity Framework Core 2.1 enable you to return non-entity types that map to tables or views and can serve as the return type from FromSql method calls.

Razor Pages, TypeScript and Knockout

calendar_today 16 July 2018 07:54

Javascript ASP.NET Core Razor Pages TypeScript

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.

Cascading Dropdowns With Blazor

calendar_today 24 May 2018 20:51

ASP.NET Core Blazor

Blazor is an experimental framework introduced by Steve Sanderson of Knockout.js fame (among other things) on the ASP.NET team. The premise of the framework is simple, but potentially game-changing for ASP.NET developers: it enables you to write your client side code in C#. What this means is that rather than having to chase after the latest Javascript-based hotness - Aurelia, React, Angular etc, only to find that they are dependent on learning a whole new load of frameworks, or that they are no longer flavour of the week, you just use the .NET skills that you already have to move your processing to the browser.

Working With JSON in Razor Pages

calendar_today 21 May 2018 13:49

ASP.NET Core Razor Pages

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.

Extending the Command Timeout in Entity Framework Core Migrations

calendar_today 26 March 2018 08:50

Entity Framework ASP.NET Core

Most migrations that you execute when working with Entity Framework Core are likely to be straightforward - resulting in nothing more than an adjustment to the database schema. Sometimes, however, you might also want to include a task that requires longer than the default command timeout value (30 seconds in SQL Server) such as importing a lot of data.

Publishing Razor Pages Applications - Gotchas

calendar_today 22 March 2018 08:15

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages ASP.NET Identity

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

ASP.NET Core Razor Pages ASP.NET Identity

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

ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

ASP.NET MVC ASP.NET Core Razor Pages

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

ASP.NET Core Razor Pages

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

Razor ASP.NET Core Razor Pages

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.

Free SSL Certificates On IIS With LetsEncrypt

calendar_today 02 February 2017 07:44

ASP.NET MVC ASP.NET Web Forms ASP.NET Core

If you have forms on your site that take a user's personal details, you should protect the page by running it under HTTPS. That way, any data that's posted from the form (email address, credit card number etc) is encrypted and hidden from prying eyes. It's not just e-commerce sites that should be protected. Intranets and other line of business apps that require authentication, blogs with comment forms that ask for email addresses and so on. The main barrier to this in the past has been the cost of the digital certificate (SSL Certificate) that asserts that you are who you say you are. LetsEncrypt is a free, automated, and open Certificate Authority that removes this barrier.

Entity Framework Core DbContext Updated

calendar_today 28 October 2016 08:50

Entity Framework ASP.NET Core

Redesigning a framework from the ground up provides an opportunity to implement an improved API. The team working on Entity Framework Core have certainly grabbed that opportunity in respect of the DbContext class, which sees a bunch of new data manipulation methods not available in Entity Framework 6 or earlier.

Entity Framework Core TrackGraph For Disconnected Data

calendar_today 11 October 2016 21:40

Entity Framework ASP.NET Core

Entity Framework Core is the new lightweight version of Entity Framework designed to work with .NET Core applications. Just like ASP.NET Core, it has been rewritten from the ground up, and includes some new ways of doing things. One of those is the introduction of the TrackGraph method for handling complex data in disconnected scenarios such as MVC or Web API applications.

Server.MapPath Equivalent in ASP.NET Core

calendar_today 02 September 2016 14:55

ASP.NET Core

Web Developers who use Microsoft technologies have always relied on the Server.MapPath method to resolve file paths in classic ASP and ASP.NET Web Forms and MVC versions up to and including 5. This method has not been included in ASP.NET Core, so what do you use instead?

Loading ASP.NET Core MVC Views From A Database Or Other Location

calendar_today 21 July 2016 08:56

ASP.NET MVC ASP.NET Core

For the vast majority of ASP.NET Core MVC applications, the conventional method of locating and loading views from the file system does the job nicely. But you can also load views from other sources including a database. This is useful in scenarios where you want to give users the option to craft or modify Razor files but don't want to give them access to the file system. This article looks at the work required to create a component to obtain views from other sources, using the database as a working example.

ASP.NET Web Pages vNext or Razor Pages

calendar_today 15 July 2016 14:09

ASP.NET MVC ASP.NET Web Pages ASP.NET Core Razor Pages

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.

Encryption and Decryption in ASP.NET Core

calendar_today 01 March 2016 13:15

ASP.NET MVC ASP.NET Core

The ASP.NET Core framework provides a new API for protecting data, including mechanisms for encryption and decryption. This article takes a quick look at how they can be used.

View Components in ASP.NET Core MVC

calendar_today 12 February 2016 08:45

ASP.NET MVC ASP.NET 5 ASP.NET Core

The ASP.NET Core MVC framework (previously known as MVC 6) includes a new feature called View Components. Here, I take a look at them, the kind of problems they are designed to solve and how to use them.

Configuring SQL Server For Session State In ASP.NET Core 1.0 MVC

calendar_today 11 January 2016 13:14

ASP.NET MVC ASP.NET 5 ASP.NET Core

This article looks at the steps required to enable SQL Server as a backing store for Session State in an ASP.NET Core 1.0 MVC application. It builds on my previous article which introduces how to configure and use session state in ASP.NET 5.

Uploading files with ASP.NET Core 1.0 MVC

calendar_today 27 October 2015 13:58

ASP.NET MVC ASP.NET 5 ASP.NET Core

Handling file uploads has changed quite a bit in ASP.NET Core. This article looks at the new objects that have been introduced to replace the old System.Web based approach from previous versions of ASP.NET. **Updated to RTM**

ASP.NET Core: Dependency Injection and Services in MVC

calendar_today 24 September 2015 08:05

ASP.NET MVC ASP.NET 5 ASP.NET Core

This is the fourth in a series of articles that explores ASP.NET Core by reconstructing the Visual Studio 2015 Web Application template from an Empty template. This article looks at the role of services and the new ASP.NET Core dependency injection system. The series of articles has been developed using Visual Studio RTM and ASP.NET Core Beta 6. It will be kept updated along with newer releases.

Sessions in ASP.NET Core

calendar_today 07 April 2015 13:39

ASP.NET MVC ASP.NET 5 ASP.NET Core

ASP.NET Core is being designed so that your application is only dependent on features that it actually needs. This is achieved in large part by creating a composable framework, where the developer opts in to non-essential features - a number of which are baked in to traditional versions of ASP.NET. One of the features that this applies to is Session State. This article looks at how to obtain and use session state in ASP.NET Core applications.