datetime

C# – Convert DateTime to string

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When you want to convert a DateTime to a string, use ToString(). By default, this converts the DateTime to a string using the current culture’s date/time format (from the OS). In most cases, you’ll want to specify the format to use. You can do this by passing in a format string consisting of format specifier … Read more

C# – TimeZoneInfo with current UTC offset

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TimeZoneInfo always shows the base UTC offset. This can be confusing because the UTC offset can change based on the date (due to daylight savings rules). Here’s an example showing DateTimeOffset and TimeZoneInfo with different offsets: You can get a date’s UTC offset from DateTimeOffset and combine it with TimeZoneInfo.DisplayName. This approach is implemented in … Read more

C# – How to use TimeZoneInfo

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Time zones are complicated and their rules can change, so it makes sense to use a library when you’re dealing with them. One option in .NET is to use the built-in TimeZoneInfo class. Here’s an example of using TimeZoneInfo to get the local system’s time zone: This outputs: Note: The display name always show the … Read more

C# – Get the current date and time

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Use DateTime.Now to get the current date/time, like this: This outputs the system’s current date/time: Note: By default, it uses the current culture’s date format (from the OS). This is showing the US date format – MM/dd/yyyy. DateTime.Now is the local date/time from the system where the code is executing. Keep that in mind if … Read more

C# – Get the last day of the month

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The last day of the month is the number of days in that month. To get the number of days in a month, use DateTime.DaysInMonth(year, month): This outputs the following: Notice that it handles leap years (2024) appropriately. Using the number of days in the month, you can get the last day of the month: … Read more

C# – Round up to the nearest 30 minutes

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Here’s how to round a DateTime up to the nearest 30 minutes: When the time is 3:38 pm, it rounds to 4:00 pm. When it’s 5:03 pm, it rounds to 5:30 pm. When it’s exactly 2:00 pm, it’ll round up to 2:30 pm (note: see the What if you’re at the start of a 30 … Read more

Get SQL Server query results as JSON

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The simplest way to get query results as JSON is to use FOR JSON PATH in the query (note: this was added in SQL Server 2016): It returns the results as a single JSON string with one JSON object per row: Note: SQL Server returns the JSON without indenting. All examples in this article show … Read more

.NET – Copy files to a specified directory after the build

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The simplest way to copy files post-build in a .NET project is to use the MSBuild Copy Task in the .csproj file, like this: Note: I’m using VS2019. My project is called NotesAPI. When I build, it logs the following messages: It copied the following build files into C:\Build\NotesAPI: In this article, I’ll explain the … Read more

C# – Parsing a DateTime from a string

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You can convert a string to a DateTime (parse) with one of these methods: I’ll show examples of using both methods for parsing various DateTime formats. Using DateTime.Parse() DateTime.Parse() can handle parsing a wide variety of culture-specific standard DateTime formats and the ISO-8601 format (which is the default date format for JSON serialization). By default, … Read more

C# – Using Channel as an async queue

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The Channel class (from System.Threading.Channels) is a non-blocking async queue. It implements the producer-consumer pattern, which has two parts: Compare this with using BlockingCollection, which is a blocking concurrent queue. In this article, I’ll show how to use a Channel. 1 – Create the Channel The first step is to create the Channel object. Here’s … Read more

C# – How to use FileSystemWatcher

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You can use the FileSystemWatcher class to detect file system changes, such as when a file is created, deleted, modified, or renamed. When a change happens, it raises an event that you can handle. This is an event-based alternative to polling for file changes. In this article, I’ll show how to use FileSystemWatcher to detect … Read more

C# – How to test that your code can handle another culture’s date format

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Let’s say you have code that converts a string to a DateTime with DateTime.Parse(): By default, DateTime.Parse() uses CultureInfo.CurrentCulture to figure out the date format. The current culture ultimately comes from your OS settings. So when you run this code on a computer that is using the en-US locale, the current culture will automatically default … Read more

C# – Log every method call

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I want to log method calls, including their parameter names and values, and what called the method. I want to minimize the amount of coding involved. For example: What options are available? In this article I’ll explain how to use the simple built-in approach. 1 – Create LogMethodCall() utility method The System.Diagnostics.StackFrame class gives us … Read more