Maclain Wiltzer

C# – Deserialize JSON to dynamic object

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If you want to deserialize JSON without having to create a bunch of classes, you can either deserialize to a dictionary or deserialize to a dynamic object with Newtonsoft.Json. Here’s an example. Let’s say you want to deserialize the following JSON: To deserialize this to a dynamic object with Newtonsoft, use JsonConvert.DeserializeObject<dynamic>: This outputs the … Read more

C# – Case insensitive dictionary

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If you want a case insensitive dictionary, use: In the Dictionary constructor you can specify how keys are compared. For string keys, the default is a case sensitive comparison. To make it case insensitive, you can pass in StringComparer.InvariantCultureIgnoreCase. Example I have a table that maps users to devices. The user-to-device mapping gets cached in … Read more

KeyNotFoundException: The given key was not present in the dictionary

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Problem The following exception is thrown when you try to get a value from a dictionary using a key that doesn’t exist in the dictionary: KeyNotFoundException: ‘The given key was not present in the dictionary.’ Consider the following the example of initializing a dictionary with a few key/value pairs, and then trying to access non-existent … Read more

How to modify app.config at runtime

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When you try to modify the app.config at runtime, if you don’t do it right, you’ll run into a few problems: System.Configuration.ConfigurationErrorsException: The configuration is read only. This article will show you how to update the app.config the right way to avoid these problems. This shows three different scenarios: inserting a new connection string, modifying … Read more

How to use relative paths in a Windows Service

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Relative paths are resolved relative to the current working directory. When you’re running a Windows Service, the default working directory is C:\Windows\system32 or C:\Windows\SysWOW64. Therefore relative paths are resolved from these system folders, which can lead to problems when read/writing files. Here are the most common problems you’ll run into: System.IO.DirectoryNotFoundException: Could not find a … Read more

Refactoring the Switch Statement code smell

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The Switch Statement code smell refers to using switch statements with a type code to get different behavior or data instead of using subclasses and polymorphism. In general, it looks like this: This switch(typeCode) structure is typically spread throughout many methods. This makes the code difficult to extend, and violates the Open-Closed Principle. This principle … Read more

C# – Fixing the Sync over Async antipattern

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The Sync over Async antipattern is when you’re using a blocking wait on an async method, instead of awaiting the results asynchronously. This wastes the thread, causes unresponsiveness (if called from the UI), and exposes you to potential deadlocks. There are two causes: In this article I’ll show an example of the Sync over Async … Read more

SqlTypeException: SqlDateTime overflow

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Problem I am executing a SQL query and trying to set a datetime column to DateTime.MinValue. I’m getting the following exception: System.Data.SqlTypes.SqlTypeException: ‘SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.’ The problem is that DateTime.MinValue is 1/1/0001 12:00:00 AM and the SQL Server DateTime minimum value is 1/1/1753 12:00 AM. Solution … Read more

Primitive Obsession code smell

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The primitive obsession code smell means you’re using primitive types (ex: string, int) excessively instead of encapsulating them in objects. This leads to sloppy code that’s error prone, such as when you have very long parameter lists full of primitives. I’ll show an example of this problem and how to fix it. Here’s a simple … Read more

C# – Log every method call

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I want to log method calls, including their parameter names and values, and what called the method. I want to minimize the amount of coding involved. For example: What options are available? In this article I’ll explain how to use the simple built-in approach. 1 – Create LogMethodCall() utility method The System.Diagnostics.StackFrame class gives us … Read more

Class Diagrams missing in Visual Studio

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Problem The Class Diagram item is missing in Visual Studio. Note: I ran into problem starting in VS2019. Solution For some reason this is not installed by default in Visual Studio, so we simply need to install it. 1. In Visual Studio click Tools > Get Tools and Features… 2. Close Visual Studio. 3. In … Read more

Refactoring the Large Class code smell

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The Large Class code smells refers to a class that has too many responsibilities. It’s doing too much. Ideally a class should only have one responsibility (Single Responsibility Principle). Code Smell: Large Class Definition: A class has too many responsibilities. Solution: Large Class code smell example Here’s an example of the Large Class code smell … Read more

Refactoring the Long Method code smell

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In this article I’ll be walking through an example of how to refactor the Long Method code smell. Code Smell: Long Method Definition: A method has too many lines of code, making it hard to understand. Solution: Long Method code smell example Here’s an example of the Long Method code smell (source: GildedRose Refactoring Kata). … Read more

The referenced component could not be found

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Problem When I open a C# project in Visual Studio, none of the references are loading. In the error list it says “The referenced component could not be found” for several references. Here’s a snippet showing just a few of the reference errors: The referenced component ‘System’ could not be found.The referenced component ‘Microsoft.CSharp’ could … Read more

HackerRank – Sock Merchant solution

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In this article, I’ll explain how to solve the Sock Merchant algorithm problem on HackerRank. Problem statement: You’re given an integer array and need to count the number of pairs of matching integers. The integers will be between 1 and 100. For example, [3,1,3] has one matching pair (the 3s match). Approach First, we know … Read more

Auto-increment build numbers in Visual Studio

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You need to auto-increment your build numbers in order to easily tell which code you’re working with. In this article I’ll explain how to auto-increment your build numbers in Visual Studio. I’ll be using text templating to generate the Assembly Version. 1 – Choose a versioning scheme I’m going to be using the version scheme: … Read more