How to mock static methods

The need to mock static methods in order to add a unit test is a very common problem. It’s often the case that these static methods are in third-party libraries. There are many utility libraries that are completely made up of static methods. While this makes them very easy to use, it makes them really … Read more

Event-driven .NET: Concurrent Producer/Consumer using BlockingCollection

With the Producer/Consumer pattern you have one or more threads producing new work and enqueuing it, and one or more threads consuming that work by dequeuing it and processing it. The consumers and producers share access to the work queue. Think of it like the Post Office. You have one or more people (producers) dropping … Read more

‘CREATE/ALTER PROCEDURE’ must be the first statement in a query batch

Problem You have a SQL query like this: While executing this you get the following error: ‘CREATE/ALTER PROCEDURE’ must be the first statement in a query batch Solution The error message says it all: the CREATE PROCEDURE statement cannot be executed after other queries in the same batch of queries. The solution is to execute … Read more

OpenQA.Selenium.DriverServiceNotFoundException: The chromedriver.exe file does not exist in the current directory

Problem I’m trying to use Selenium with the ChromeDriver and I’m running into the following exception: Unhandled Exception: OpenQA.Selenium.DriverServiceNotFoundException: The chromedriver.exe file does not exist in the current directory or in a directory on the PATH environment variable. The driver can be downloaded at http://chromedriver.storage.googleapis.com/index.html Solution The simplest solution is to install the Selenium.Chrome.WebDriver nuget … Read more

OpenQA.Selenium.WebDriverException: Element is not clickable. Other element would receive click.

Problem I am using Selenium to automate navigating a website. I’m trying to click a button: When I try to click the button it’s throwing the following exception: OpenQA.Selenium.WebDriverException: Element is not clickable. Other element would receive click. The reason this is happening is because Selenium is trying to click the button by its coordinates, … Read more

Event-driven .NET: How to use query notifications in SQL Server to monitor database changes

How do you check for new records in a database and react to the new data? You really only have two options: Poll for changes every X seconds Use query notifications to be notified when new data is inserted In this article I’ll show you how to configure query notifications so that your application receives … Read more

Event-driven .NET: How to add an event to a class

In the previous article we saw how events work. In this article I’ll show how to add an event to a class. In order to illustrate this I’ve created a simple chat app that uses an in-memory message queue. Each chat window is subscribed to the message queue’s OnMessageReceived event, and updates their UI upon … Read more

Event-driven .NET: how events work

The very basis of event-driven programming is the concept of events. Events are an implementation of the Observer Pattern. With the Observer Pattern you have an observable entity and entities that want to observe that entity. Objects with events are observable, and other objects subscribe to those events and are notified when the events happen. … Read more