json

Modifying JSON in SQL Server

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There are two ways to modify JSON data in a SQL Server table: In this article, I’ll show how to insert, update, and delete JSON data by using the JSON_MODIFY() function. I’ll also show how to deal with JSON arrays. Note: This is part 2 of the mini-series about the SQL Server JSON API. The … Read more

Querying JSON in SQL Server

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In SQL Server 2016, Microsoft added support for handling JSON data: The JSON API in SQL Server is well-suited for simple scenarios where you only need to do basic querying and manipulation. For advanced querying, the SQL Server JSON API gets complicated and hard to use, so you may want to look into other options. … Read more

Serializer options cannot be changed once serialization or deserialization has occurred

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Problem When using System.Text.Json, it’s a good idea to reuse JsonSerializerOptions objects. This leads to a massive 200x speedup in subsequent calls to the serializer. The downside is you can’t change properties on the options object after you’ve passed it in a Serialize()/Deserialize() call. You’ll get the exception: System.InvalidOperationException: Serializer options cannot be changed once … Read more

C# – How to read configuration from appsettings.json

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The appsettings.json file is a convenient way to store and retrieve your application’s configuration. You can add it to any project and then use the Microsoft.Extensions.Configuration library to work with it. Since appsettings.json is just a JSON file, you can add any section / values you want (this is easier than working with XML-based app.config … Read more

C# – Reuse JsonSerializerOptions for performance

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Reusing JsonSerializerOptions (from System.Text.Json) is optimal for performance. It caches type info, which results in a 200x speedup when it deals with the type again. Therefore, always try to reuse JsonSerializerOptions. I’ll show a speed comparison of serializing with and without reusing JsonSerializerOptions. Measuring the performance gains of reusing JsonSerializerOptions To measure the performance gains … Read more

Newtonsoft: Self referencing loop detected for property

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Problem When you try to serialize an object using Newtonsoft.Json and there’s a circular reference, you get the following exception: Newtonsoft.Json.JsonSerializationException: Self referencing loop detected for property Here’s an example of code that results in this exception: The Parent object references the Child object, which references the Parent object. Hence, a circular reference (aka a … Read more

JsonException: The JSON value could not be converted to Enum

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When you’re using System.Text.Json to deserialize JSON that contains the string representation of an enum, you get the following exception: System.Text.Json.JsonException: The JSON value could not be converted to <Enum Type> The following JSON would cause this exception. Conference is an enum, and this is using the string representation “NFC” instead of the numeric value … Read more

C# – Case sensitivity in JSON deserialization

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By default Newtonsoft does case insensitive JSON deserialization and System.Text.Json does case sensitive JSON deserialization. Case sensitivity comes into play when a JSON string is being deserialized into an object. If you’re using case sensitive deserialization, then keys in the JSON string must match type names exactly, otherwise it won’t deserialize the class/property with the … Read more

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

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Before .NET 5, the built-in JSON serializer (System.Text.Json) couldn’t handle serializing a dictionary unless it had a string key. Here’s an example running in .NET Core 3.1 to show the problem. This is initializing a dictionary with values and then attempting to serialize it. This results in exception: System.NotSupportedException: The collection type ‘System.Collections.Generic.Dictionary`2[System.Int32,System.String]’ is not … Read more

Common Newtonsoft.Json options in System.Text.Json

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If you’re switching from Newtonsoft.Json to System.Text.Json (or vice versa), you may be wondering how to specify the common options you’re used to using in Newtonsoft. For example, how do you specify the equivalent of Newtonsoft.Json.Converters.StringEnumConverter in System.Text.Json? The following table shows a few common serialization options used in Newtonsoft.Json and their equivalents in System.Text.Json. … Read more

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