Is polymorphic deserialization possible in System.Text.Json? The answer is yes and no, depending on what you mean by “possible”. There is no polymorphic deserialization (equivalent to Newtonsoft.Json’s TypeNameHandling) support built-in to System.Text.Json. This is because reading the .NET type name specified as a string within the JSON payload (such as $type metadata property) to create … Read more
In .NET 6, extension methods are being added to JsonSerializer to deserialize an object directly from a JsonElement or JsonDocument: public static partial class JsonSerializer { public static TValue? Deserialize<TValue>(this JsonDocument document, JsonSerializerOptions? options = null); public static object? Deserialize(this JsonDocument document, Type returnType, JsonSerializerOptions? options = null); public static TValue? Deserialize<TValue>(this JsonDocument document, JsonTypeInfo<TValue> … Read more
The issue turned out to be that I was still referencing Microsoft.AspNetCore.Razor.Design Version=”2.2.0″ in the .proj file’s package references. Deleting that reference (which isn’t needed at all as Razor.Design is now part of AspNetCore library) fixed the issue. Once I’d done that, I then got hundreds of errors about nullable objects being a new feature … Read more
See the announcement for ASP.NET Core 3 Preview 4, which explains that this tool is no longer built-in and requires an explicit install: The dotnet ef tool is no longer part of the .NET Core SDK This change allows us to ship dotnet ef as a regular .NET CLI tool that can be installed as … Read more