FoxLearn | How to

How to Get a file’s checksum using any hashing algorithm in C#

By Tan Lee Published on Mar 20, 2025 150

This article demonstrates how to calculate a file’s checksum using several hashing algorithms, including MD5, SHA1, SHA256, SHA384, and SHA512.

How to Get a file’s MD5 checksum

By Tan Lee Published on Mar 20, 2025 119

To retrieve a file’s SHA256 checksum, you can use the Get-FileHash cmdlet. This feature has been available since PowerShell v4.

Handle a faulted Task’s exception in C#

By Tan Lee Published on Mar 20, 2025 165

When a Task throws an exception and ceases execution, it becomes "faulted." The key question is: how do you access the exception thrown by a faulted Task?

Serializer options cannot be changed once serialization or deserialization has occurred

By Tan Lee Published on Mar 20, 2025 99

When using System.Text.Json, it’s highly recommended to reuse JsonSerializerOptions objects, as this provides a significant speed boost (up to 200 times faster) for subsequent serialization and deserialization operations.

How to use format strings with string interpolation in C#

By Tan Lee Published on Mar 20, 2025 113

In C#, interpolated strings follow this structure: {variable:format}, where the format part is optional. Normally, the interpolated string would look like this: $"My name is {name}".

How to Query JSON in SQL Server

By Tan Lee Published on Mar 20, 2025 124

Since SQL Server 2016, Microsoft has provided built-in support for managing and querying JSON data. This enables users to store, retrieve, and manipulate JSON documents directly within SQL Server.

How to modify JSON in SQL Server

By Tan Lee Published on Mar 20, 2025 150

In SQL Server, there are a couple of ways to modify JSON data within a table:

How to Check if an IP range is valid in C#

By Tan Lee Published on Mar 20, 2025 112

If you have an IP range defined by a starting and ending IP address (e.g., from user input or a configuration file), you can validate it using the following steps: