C# – How to match an anonymous type parameter in a mocked method

When an anonymous type is defined in one assembly, it won’t match an anonymous type defined in another assembly. This causes problems when you’re unit testing and trying to mock a method that has an an anonymous type parameter. For example, let’s say you’re trying to unit test the following method: To unit test this, … Read more

ASP.NET Core – How to change the JSON serialization settings

System.Text.Json is the default JSON serializer in ASP.NET Core. It uses the following default serialization settings: To change the settings at the service level for all controllers, call AddJsonOptions() in Startup.ConfigureServices() like this: Note: This example is passing in JsonStringEnumConverter, which makes JsonSerializer use the enum name instead of enum value. When you change the … Read more

C# – Newtonsoft extension methods for HttpClient

System.Net.Http.Json provides extension methods that simplify getting and sending JSON with HttpClient. Internally, it uses System.Text.Json for serialization. What if you want to use Newtonsoft instead of System.Text.Json? You can use the following extension methods for that: These are modeled off of the extension methods in System.Net.Http.Json. You can pass in a JsonSerializerSettings object to … Read more

C# – Get and send JSON with HttpClient

The simplest way to get and send JSON with HttpClient is to use the GetFromJsonAsync() and PostAsJsonAsync() extension methods found in System.Net.Http.Json, like this: Note: You have to install the System.Net.Http.Json nuget package if you’re using a framework version before .NET 5. These extension methods use System.Text.Json for serialization. They simplify things by abstracting away … Read more

System.Text.Json – Using anonymous types to customize serialization

It’s common to need to customize serialization. When you need to do this, you’d typically need to create a custom converter and pass it in during serialization. Depending on your scenario, an alternative approach is to use anonymous types, like this: Basically you select properties from another object and format them as desired, and then … Read more

System.Text.Json – How to serialize non-public properties

By default, the System.Text.Json.JsonSerializer only serializes public properties. If you want to serialize non-public properties, you can create a custom converter and use reflection to get the non-public properties too, like this: Use the custom converter by adding it to JsonSerializerOptions.Converters and passing the options in when serializing, like this: In this article, I’ll show … Read more

System.Text.Json.JsonException: The JSON value could not be converted to System.DateTime

When deserializing a datetime value with System.Text.Json.JsonSerializer, if the value isn’t in the format it expects, then it’ll throw a JsonException. It expects datetimes to be in the ISO-8601-1:2019 format (for example: 2021-07-12T12:35:34+00:00). For example, the following code is trying to deserialize a datetime value in an unexpected format: This’ll throw the following exception: System.Text.Json.JsonException: … Read more

Deserializing JSON that contains an embedded JSON string

When you send mail, you put a letter in an envelope and put routing information on the envelope. The postal service uses the routing information to deliver the envelope to a specific mailbox. The mailbox owner then opens the envelope and reads the letter. Sometimes you may need to deal with the JSON equivalent of … Read more

System.Text.Json – How to customize serialization with JsonConverter

Most of the time JsonSerializer will get you want you want. You can pass in options to control serialization to a certain extent. But sometimes you’ll run into scenarios where you need to customize how it handles serialization for a specific type. This is where JsonConverter comes in. To customize serialization for a specific type, … Read more