Set a Breakpoint and Start Debugging in Visual Studio

I didn't know I could do this until a few weeks ago: While still in Edit mode, you can right-click on a line of code and select Run to Cursor. Visual Studio will compile your application (if necessary), start your application in Debug mode and stop on the line you've selected. If your cursor is already on the line where you want to stop, you don't need to touch your mouse -- just press Ctrl+F10 to get the same result. Once Visual Studio stops on your line, you can set more permanent breakpoints by pressing F9.

Posted by Peter Vogel on 09/09/20140 comments

To Sync or Not to Sync

One reader's comments in an article I wrote about Entity Framework's async programming  turned into an interesting discussion on the role of asynchronous programming in the modern world (interesting for me, at any rate). Back in the day, I used to tell developers that the surest way to create a bug they'd never be able to track down was to write what we used to call "multi-threaded applications." I gave seminars on designing multi-threaded application where, perversely, I spent the first five minutes explaining why you shouldn't do multi-threading unless you absolutely had to. And then, of course, I'd go home and write multi-threaded applications for my clients: do as I say, not as I do.

Posted by Peter Vogel on 07/08/20140 comments

Return an Interface from Your Methods for Maximum Flexibility

If I'm writing a method that returns a collection, I can, of course, declare my method's return type using a class name, like this:

Public Function GetCustomersByCity(City As  String) Returns List(of Customer)

But by declaring my return type as class in this way, I restrict my method to only returning that class (in this example, a List). I might eventually want to rewrite the method to return some other class, but my overly-specific return type will prevent me from doing that. A much better practice is to just specify an interface name when returning a collection. That allows me to return any class I want, provided I pick a class that implements the interface I choose.

Posted by Peter Vogel on 06/28/20140 comments

The Easy Way to Change Your Visual Studio Color Scheme

For all the complaints about the muted color scheme in Visual Studio 2012, it's actually pretty easy to change the colors. Just go to Tools | Options and you'll find that the Environment node includes a Visual Theme choice (there's no equivalent feature in Visual Studio 2010, but then, no one complains much about Visual Studio 2010's color scheme).

Posted by Peter Vogel on 06/27/20140 comments

How to Concatenate Collections into Strings

I was writing a For…Each loop yesterday to create a comma-delimited string from the properties of objects in a collection (and, thanks to LINQ, I don't write many For…Each loops any more). As I was typing in my code I noticed that the String class's Join method now accepts a collection as one of its parameters. That let me delete my whole For…Each loop because, with this new version of Join, all I have to do is pass the Join method the separator I want between my strings (in this case, a comma) and a collection of strings.

Posted by Peter Vogel on 06/17/20140 comments

One Simple Tip to Fix the ObamaCare Web Site

According to the Time magazine article about the team that fixed the ObamaCare site, the first thing the team did was build in a cache (in fact, they were horrified to discover that the site was built without a server-side cache for frequently used data). If you're reading this Web site, you already knew about that and how easy it is to implement using either the ASP.NET Cache object on the server or local storage on the client. It could have been you on that team.

Posted by Peter Vogel on 06/09/20140 comments

Writing Flexible Entity Framework Methods with Set

Every once in a while I find myself writing one set of code to do something to the Customers collection and then writing almost identical code work with the Orders collection. When I spot that duplicate code, I use the Set method on the DbContext object to find the collection of entities I want and write the code once. I just pass the Type of the object I want to the Set method.

Posted by Peter Vogel on 05/30/20140 comments

Making Generic Classes Useful with Constraints

Many developers are aware that they can write a method that works with many different kinds of objects without using the Object data type: Just write a generic class or method. For example, this method will work with any class, provided that the developer specifies the class when calling the method:

Public Sub MyMethod(Of T)()
  Dim im As T
  '...using the variable im
End Sub

Posted by Peter Vogel on 05/27/20140 comments

Defining Natural Keys in Entity Framework Entity Classes

It's not something database developers do much anymore, but it is possible to have a primary key in a table that isn't generated by the database. If you do have a key like that, here's what you have to do: when writing an entity class in Entity Framework, you need to tell Entity Framework about it by flagging the corresponding property in the entity class. You do that by decorating the property with the DatabaseGenerated attribute and specifying a DatabaseGeneratedOption.

Posted by Peter Vogel on 05/19/20140 comments

Speed Up Entity Framework Startup

Before your first query against an Entity Framework (EF) model, EF gathers data about your database based on the entities and relationships you've defined to EF; then EF does it again before your first save. If you have lots of entities and relationships in your model, the information-gathering phase can take awhile. Just to make it worse: doubling the number of entities in a model seems to more than double the time in the information-gathering phase. Let's not ask how I know this.

Posted by Peter Vogel on 05/01/20140 comments

Free Tool: Convert C# to Visual Basic or Visual Basic to C#

I recently got some feedback from readers about using Visual Basic rather than C# for the sample code in my Practical .NET column. Ironically, the feedback came just before I started doing a whole bunch of columns with code in C# (the columns are about Entity Framework 6 and I used Entity Framework Power Tools to generate my entity code; sadly, Power Tools for Entity Framework 6 is still in beta and only produces C# code).

Posted by Peter Vogel on 04/25/20140 comments

Limiting Your Entity Framework Models

If you're not reading Julie Lerman's Data Points column over at MSDN Magazine, you're missing out (in fact, I just realized that my recent column and her column are almost the same, except that hers covers more stuff). I especially appreciated her columns on Domain-Driven Design. And those columns got me thinking about where I should put my Entity Framework (EF) code.

Posted by Peter Vogel on 04/21/20140 comments