Cycling Through All of the Object References in Visual Studio

You're thinking about making a change to that Transaction class but you're not sure how big an impact that change will have. One way to answer that question is to find all the places that the class is used.

Your first step is to click on the class name (and click on it in any place you find it, by the way). Then press Shift-F12 or right-click on it and pick Find All References. That opens a References window showing the statements that refer to your object (that window typically opens below your editor window).

Posted by Peter Vogel on 03/12/20190 comments

Initializing a Project with an Existing Database

Eight-five percent of all application development is spent on existing systems, with existing databases. If you want to use Entity Framework's code-first development (where the database schema is an "implementation detail" generated from your object design) and migrations (which modifies your existing schema as your object model evolves), how do you do that with an existing database?

Posted by Peter Vogel on 03/11/20190 comments

Designing with the Dependency Inversion Principle

The Dependency Inversion Principle says "the interface belongs to the client." As I've said elsewhere, adopting this principle means a reversing of the way applications used to be built: Design the database, build the objects to maintain the tables, wrap a UI around those objects and then bring the users in for training because they'd never figure the application out on their own.

Posted by Peter Vogel on 02/27/20190 comments

Redirect Code in .NET Core

There are four Redirect help methods built into your .NET Core Controllers that you can use to tell a client that a resource exists ... but not at this URL. For all these cases, you should also be setting your response's Location header to tell the client where to find the result the client originally requested.

Posted by Peter Vogel on 02/25/20190 comments

Returning Files from .NET Core or ASP.NET MVC Controllers

In ASP.NET MVC, the File helper method built into your controller gives you multiple options for retrieving the file you want to send to the client. You can pass the File helper method an array of bytes, a FileStream or the path name to a file depending on whether you want to return something in memory (the array of bytes), an open file (FileStream) or a file on your server's hard disk (a path).

Posted by Peter Vogel on 02/22/20190 comments

Enabling Docker Support

If you've got Visual Studio 2017, you can run your application in Docker (even with the Community Edition).

First, you'll need to download Docker for Windows. You'll need to decide what operating system will be used inside your containers (Windows or Linux). For .NET MVC Core applications and Web services, it doesn't matter which you pick, though generally speaking, I'd say there are more resources available if you choose Linux.

Posted by Peter Vogel on 02/19/20190 comments

Understanding Docker Vocabulary

The purpose of Docker is to build containers that hold, potentially, all of the components of an application: the application itself, the database engine, any Web services it requires and so on. That container, unlike a virtual machine, doesn't require an operating system so it takes less space than a VM and starts up/shuts down faster.

Posted by Peter Vogel on 02/11/20190 comments

Extending the ASP.NET Core Processing Pipeline

I've done at least a couple of articles on how to support adding custom processing to every request to your ASP.NET MVC site (most recently, an article on HTTP Modules and Handlers). In ASP.NET Core the process is very different (of course) but it's actually much simpler.

Posted by Peter Vogel on 01/11/20190 comments

Bundling Scripts in ASP.NET Core

In ASP.NET MVC Core the BundleConfig class -- where, in ASP.NET MVC, you used code to create script bundles in ASP.NET MVC -- is gone. Instead, you use a configuration file called bundleconfig.json to name your bundles and assign files to them.

This sample code combines two JavaScript files into a bundle called site.min.js (it also triggers minifying all the files added to the bundle):

Posted by Peter Vogel on 01/10/20190 comments

When the Watch Window in Visual Studio Doesn't Update

While debugging in Visual Studio, you may notice, when you check some value in the Watch window, one of two icons beside your data. You may get one or the other of a circle with two wavy lines inside of it or the standard refresh icon of two curved arrows chasing each other. Either icon indicates that the data being displayed in the Watch window isn't up to date.

Posted by Peter Vogel on 01/09/20190 comments

Lazy Loading in Entity Framework Core

Microsoft has emphasized that, while LINQ code is "copy and paste" compatible from Entity Framework 6 to Entity Framework Core, you should do a lot of testing to make sure that any code you copy behaves the same way in its new environment as it did in the old (you really get the impression that Microsoft doesn't think you can do enough testing).

Posted by Peter Vogel on 01/08/20190 comments

An Ad Hoc Approach to Passing Elements from Blazor to JavaScript

In a previous column I described an architectural, design-pattern-based approach to integrating JavaScript and Blazor code. However, if you just need to pass one element from your Blazor page to some JavaScript functions, that approach might be overkill.

Posted by Peter Vogel on 12/06/20180 comments