C#

What’s new in C# 14? Extension members (extension properties and static extension members), the field keyword, null-conditional assignment with ?.=, nameof(List<>), implicit span conversions and a few smaller upgrades. In this tutorial, I’ll run what’s new in C# 14 one feature at a time. Each one gets a tiny .NET 10 program, its real output … Read more >>

To send email with attachment in C#, build the message with MailKit’s BodyBuilder, call builder.Attachments.Add() with a file path, a byte array or a stream, and send it with MailKit’s SmtpClient. Microsoft now advises against System.Net.Mail.SmtpClient for new code. I sent every message below on .NET 10 to a local test SMTP server, so you’ll … Read more >>

Say you run checkout for a Denver outdoor store, and marketing changes the discount every week: 10% off one week, $15 off orders over $100 the next. Delegates in C# handle that cleanly. A delegate is a type-safe variable that holds a method, so checkout calls whichever rule you plug in at run time, with … Read more >>

Our Seattle warehouse team wanted an audit line for every order and an email when a standing desk drops below five units. Events in C# handle that cleanly: the order code announces what happened and never needs to know who’s listening. In this tutorial, I’ll build that order service step by step and show you … Read more >>

Most people’s first try at multiple inheritance in C# looks like class Thermostat : Device, WifiModule. It won’t compile. The .NET 10 compiler stops with CS1721, because a C# class can have only one base class. Quick answer: keep one base class and implement as many interfaces as you need: class Thermostat : Device, INetworked, … Read more >>

Prices that print as 25 instead of 25.00 look broken to anyone reading a receipt. The fix for C# 2 decimal places is short: convert the int to a double and call ToString(“F2”), or round the value with Math.Round(value, 2). In this tutorial, I’ll show you every way I handle C# 2 decimal places in … Read more >>

To convert int to hex string with leading zeros in C#, call ToString(“X4”) and put the digit count you want after the X. Use a lowercase x for lowercase digits: That’s 255 printed as 00FF, 000000ff and 0xFF. I ran every example below on .NET 10, including the negative numbers and byte arrays that trip … Read more >>

Turning 42 into 00042 takes one call in C#: “42”.PadLeft(5, ‘0’) for a string, or 42.ToString(“D5”) for an int. Both give you a five-character result with zeros in front. In this tutorial, I’ll show every way I use to add C# leading zeros: PadLeft, the D and 00000 formats, interpolation, negative numbers, values longer than … Read more >>

Parsing “00042” in C# gives you 42, every time. When you convert a string to int, leading zeros are dropped, because an int stores a value, not the digits you typed. In this tutorial, I’ll pin down how to convert string to int with leading zeros in C# on .NET 10: parse the number, then … Read more >>

The quickest way to get the first character of each word in a string in C# is to split the text into words, take w[0] from each one with LINQ Select, and join the letters with string.Concat: I ran it on .NET 10 against messy spacing, hyphens, lowercase acronyms, null input and the one emoji … Read more >>