.NET asp.net debugging Developer Tips Tech Tricks & Resources

Top 10 Debugging Tips for .NET

Top 10 Debugging Tips for .NET
Stackify Loves DevelopersStackify Loves DevelopersAdding nse to the expression prevents evaluation

One of the best-laid plans of mice and males nonetheless go off the rails typically. Even whenever you’ve been rigorous and put unit checks in place, there are occasions whenever you’ll need to leap in and debug an software or a unit check. On this article, we’ll check out 10 debugging ideas for .NET.

1. Setting Breakpoints

A breakpoint is likely one of the elementary models of debugging. It’s a trace to the debugging surroundings that it ought to cease the execution of the appliance at a sure level. Should you’re utilizing the complete Visible Studio IDE, then including a breakpoint is straightforward. Click on within the gutter subsequent to the road of code on which you need to halt execution.

Breakpoints might be added to virtually any line of code that’s executed. This implies that you could’t breakpoint on the [Fact] attribute on this code or on the precise perform identify. Within the former case, you’ll be able to drop into the definition of the attribute, if you want to break on it. Within the latter, breakpointing on the primary line of the perform will cease execution earlier than the perform has been executed. Breakpoints might be added earlier than you execute the code or when you’re debugging.

2.Breakpoints with circumstances

Typically a bit of code could also be executed a bunch of occasions earlier than you encounter the circumstances you’re wanting for. As an example, you is perhaps working with a set and the 93rd factor is the one you should debug. You might sit and hit F5 92 occasions to get to the report through which you’re , or you would use a conditional breakpoint. Conditional breakpoints will solely trigger the method to halt when a situation is met. The circumstances may be quite simple like counting the variety of occasions a line has been hit. They may also be extra complicated like checking if some worth is true.

One underused function within the circumstances dialog is setting a breakpoint when a worth modifications. This may be actually helpful for those who’re making an attempt to trace down what’s altering the worth of some variable. Moreover there’s a checkbox for performing an motion when the breakpoint is hit. You’ll be able to shortly add short-term logging to a operating software on this means.

three. Viewing return values

Typically, you should use the mouse to hover over a variable when debugging to get an concept of what worth is held within the variable. One place the place you possibly can’t do that is for getting the return worth from a perform. You possibly can’t merely hover over the return assertion and get a preview of what will be returned from the perform. To tug a worth, you’ll be able to look in two locations: the watches and locals.

Within the locals window, you possibly can see the return worth by wanting for the identify of the perform (absolutely certified, in fact) adopted by the phrase “returned”. I put a breakpoint on the closing brace from the perform to see the worth which might be returned.

Within the watch window, you possibly can check with the present return worth by analyzing a particular variable referred to as $ReturnValue


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four. Modifying values

With the ability to see a worth within the watch panel is one factor, however in contrast to my youngsters in any retailer that sells china, you’re allowed to poke at issues. If you want to simulate some return worth or examine what would occur with a selected, difficult-to-reproduce set of variables, then it may be carried out by poking into the values proven within the locals window. This system is especially helpful if in case you have a boundary situation you want to check out, however aren’t positive methods to arrange the inputs to get the outputs you want. Within the video under, you’ll be able to see a preview of the sum of first and final as offered by our subsequent debugging tip: OuncesCode.

5. OZ Code

Visible Studio is the Cadillac of IDEs in terms of debugging, as in contrast with most another IDE. Including OuncesCode straps a set of rocket boosters to it. It offers a wealthy set of instruments that make debugging even simpler. I’m notably keen on the modifications it makes to the show of code throughout a debugging session. You possibly can see, within the video above, the values of variables are proven inline with out having to hover over them. As well as, you’ll be able to search inside a posh object or collections of objects for particular values.

You’ll be able to learn all concerning the options of OuncesCode over on their website. The device isn’t free, however it’s a worthwhile addition to your toolbelt. For those who’re working in a code base that isn’t simply examined with unit checks, the acquisition is doubly worthwhile.

6. Add a unit check

Typically one of the best type of debugging shouldn’t be debugging. The factor with debugging is that it tends to be fairly a sluggish course of. You might want to arrange a check case, set some breakpoints, and run via the appliance to get to the place it’s essential to be to train the conduct you want to debug. I’ve discovered this to be a really irritating expertise prior to now. Graphical purposes steadily require spending a bunch of time clicking on buttons to get to the situation with the issue.

As an alternative of scuffling with this, it’s possible higher that you simply arrange a unit check to train the perform in query with precisely the values you want. The methods introduced so far on this article could also be helpful in getting you to a state the place you understand which values are inflicting an issue. These can then be extracted right into a unit check to tighten up the debugging cycle. You possibly can, in fact, debug into the unit exams to actually zero in on the issue.

There are numerous nice unit testing instruments, a few of which may even generate some exams for you. Leveraging these instruments and constructing a set of unit exams might scale back the variety of occasions that you need to drop to debugging sooner or later. The top result’s that you simply’ll really feel extra snug about altering code sooner or later, understanding you could have a security internet of checks to fall again on.

Bonus Tip: Verify in with Prefix

You may consider Prefix as only a device for getting some perception into what your code is doing, nevertheless it’s greater than that. You should use Prefix to seek out the whole lot from n+1 errors to hidden exceptions and getting code ideas. Often wanting on the logs as surfaced by Prefix might be sufficient to level you in the suitable course to repair your bug. Prefix can simply run on a regular basis even once you’re doing the preliminary improvement so you possibly can catch bugs whereas they’re nonetheless in your pc and also you don’t should debug issues in manufacturing.

Learn Why APM Utilization is Shifting Left to Improvement and QA.

Troublesome to check code

In case your codebase is troublesome to check, and there are a few of these on the market, you then may need to decide up a replica of Michael C. Feathers’ ebook “Working Effectively with Legacy Code”. The appendix on this ebook provides concrete recommendation about easy methods to extract testable code from a jumble of untestable code.

7. Breakpointing in LINQ

I’m a LINQ addict. There, I’ve come out and stated it. There isn’t a software I construct that doesn’t make heavy use of LINQ. I just like the useful nature of with the ability to type, filter, and undertaking in a really terse means. My mind is used to parsing and understanding complicated queries, and I do know that considered one of my shortcomings as a developer is writing unapproachable LINQ statements. Historically, debugging LINQ has been fairly complicated and the recommendation within the Microsoft documentation is fairly scant. You possibly can debug by choosing chunks of the question at a time and evaluating them within the fast watch or watch home windows. This leaves one thing to be desired.

OuncesCode has a pleasant visualizer that may present how the info in a LINQ question is altered at every step. Right here you’ll be able to see a question that takes a bunch of phrases, filters them for size, grabs the primary letter, teams them, and finds the most important rely.

The question is displayed as a collection of panels displaying the state of the info after a step has been taken. There are a few caveats right here: You’ll be able to’t do that for LINQ queries which are based mostly on exterior knowledge. This consists of Entity Framework queries that basically simply generate SQL. Additionally there’s at present solely help for visualizing full-framework LINQ queries.


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eight. Evaluating features with no uncomfortable side effects

A well-designed technique in practical programming has no unwanted side effects. That’s to say, you possibly can run the identical perform a number of occasions with the identical inputs and the outcomes might be similar. That is referred to as a pure perform and it allows all types of enjoyable with caching and optimizing. Sadly, most features we encounter usually are not pure and should properly have a aspect impact. Contemplate this perform:

static int hitCounter = zero;
public static int GetAndIncrement()

return hitCounter++;

Each time this perform is known as, the result’s totally different: zero, 1, 2, three. That is true for those who’re evaluating the perform in a fast watch window too.

Each time the perform is evaluated there’s a aspect impact of the hit counter is incremented. That is a simple situation to hit when debugging your code. To keep away from altering the state of the operating program whereas we’re debugging, we will add “, nse” to the expression.

Adding nse to the expression prevents evaluation

9. Debugging in VSCode

In the event you’re engaged on a challenge that isn’t utilizing the complete model of Visible Studio, then you possibly can nonetheless get a wealthy debugging expertise by leveraging Visible Studio Code. The debugging expertise in VSCode isn’t fairly nearly as good as that of full VS, however it’s nonetheless jolly good. The swish instruments present in OuncesCode haven’t made an look in VS Code but. You possibly can debug an entire host of various languages utilizing VSCode: from Java to Python to C#, and all of them are supported by way of a collection of plugins. The documentation on learn how to begin debugging can also be nice and could be the one start line you want.

10. Speak it out

That is in all probability the only most necessary factor you are able to do to debug your code. Discover a good friend, a coworker, or an inanimate object, and speak about the issue you’re having. I discover that merely the act of getting my ideas collectively sufficiently to elucidate the issue to anyone else is sufficient to level me within the course of an answer. Typically the only options are higher than a world of slick debugging instruments.

About Simon Timms

Simon is a polyglot developer who has labored on every part from serial port drivers on an Android pill, to NServiceBus, to processing tens of hundreds of messages a second utilizing stream analytics, to constructing Angular net purposes. All that within the final yr. He’s the writer of a variety of books on JavaScript and ASP.NET and blogs far much less repeatedly than he ought to on each the Western Dev’s website (http://westerndevs.com) and on his weblog (http://blog.simontimms.com). He’s additionally the least seen member of the ASP.NET monsters (http://aspnetmonsters.com).His pursuits change as ceaselessly as he modifies his underwear. In the mean time he’s interested by F# and the way AI goes to vary how we develop software program. He’s an enormous image specialist who can keep a cogent view of a whole system and decide the correct know-how to unravel an issue.