C# – Merge two dictionaries in-place

When you merge two dictionaries, you can either merge them in-place, or create a new dictionary and copy the values over to it. The following extension method does an in-place merge of two dictionaries. It puts items from the right dictionary into the left dictionary. When duplicate keys exist, it’s keeping the value from the … Read more C# – Merge two dictionaries in-place

System.Text.Json can’t serialize Dictionary unless it has a string key

The built-in JSON serializer in .NET Core can’t handle serializing a dictionary unless it has a string key. When I run this code I get the following exception: System.NotSupportedException: The collection type ‘System.Collections.Generic.Dictionary`2[System.Int32,System.String]’ is not supported. It can only serialize dictionaries with string keys. This is bizarre, and another reason to stick with Newtonsoft for … Read more System.Text.Json can’t serialize Dictionary unless it has a string key

C# – Cannot convert null to type parameter ‘T’ because it could be a non-nullable value type

Problem You’re trying to return null from a generic method and you’re getting the following compiler error: Cannot convert null to type parameter ‘T’ because it could be a non-nullable value type. Consider using ‘default(T)’ instead You can’t return null because the compiler doesn’t know if T is nullable. Solution There are a few options … Read more C# – Cannot convert null to type parameter ‘T’ because it could be a non-nullable value type

C# – Use Convert.ChangeType to convert string to any type

You can use Convert.ChangeType() to convert from a string to any type, like this: Normally you’d call the specific type converter method, like Convert.ToBoolean(“true”). However, sometimes it makes sense to use the generalized type converter method – Convert.ChangeType() – instead of hardcoding the calls to specific type converter methods. I’ll show an example of when … Read more C# – Use Convert.ChangeType to convert string to any type

C# – Load all types that implement an interface in the current assembly

To get all types in the current assembly that implement a specified interface, use the following: To create instances of these types, loop through them and use Activator.CreateInstance(), like so: Example – Auto-wire a command routing table Let’s say we want to build a command routing table. We have commands and want to automatically wire … Read more C# – Load all types that implement an interface in the current assembly

C# – Generic Plugin Loader

This article explains how to create a generic plugin loader that solves many real world problems when loading plugins in .NET. Besides being generic, this plugin loader also solves the following real world problems when working with plugins: Loads assemblies that have dependencies. Load assemblies that have unmanaged dependencies (like C++ DLLs). Solves the “IsAssignableFrom … Read more C# – Generic Plugin Loader

Multithreaded quicksort in C#

One day I decided to challenge myself by trying to implement multithreaded quicksort. I wanted to see how it would compare to the built-in sort function – Array.Sort(). I came up with two algorithms that were 2-4x faster than Array.Sort(): Top-down: divide-fork-sort-merge Bottom-up: quicksort with fork-on-recursion After continuing to tinker, in attempts to further optimize, … Read more Multithreaded quicksort in C#