How to Convert a JsonElement or JsonDocument to an Object in System.Text.Json?

Equivalent function in System.Text.Json

The Json.NET framework provides a ToObject() method to convert JToken to a class. However, there is no direct equivalent of this method in System.Text.Json.

Workaround for .NET 6 and above

In .NET 6, extension methods were introduced that allow objects to be deserialized directly from a JsonElement or JsonDocument. These methods are:

<code class="language-csharp">public static TValue? Deserialize<TValue>(this JsonDocument document, JsonSerializerOptions? options = null);
public static object? Deserialize(this JsonDocument document, Type returnType, JsonSerializerOptions? options = null);</code>

Example:

<code class="language-csharp">using var jDoc = JsonDocument.Parse(str);
var myClass = jDoc.RootElement.GetProperty("SomeProperty").Deserialize<SomeClass>();</code>

Workaround for .NET 5 and earlier

In .NET 5 and earlier, these extension methods do not exist. Please consider using the following workarounds:

<code class="language-csharp">public static T ToObject<T>(this JsonElement element, JsonSerializerOptions options = null)
{
    var bufferWriter = new ArrayBufferWriter<byte>();
    using (var writer = new Utf8JsonWriter(bufferWriter))
        element.WriteTo(writer);
    return JsonSerializer.Deserialize<T>(bufferWriter.WrittenSpan, options);
}

public static T ToObject<T>(this JsonDocument document, JsonSerializerOptions options = null)
{
    if (document == null)
        throw new ArgumentNullException(nameof(document));
    return document.RootElement.ToObject<T>(options);
}</code>

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