Asynchronous programming is essential for building responsive applications, but it comes with challenges - particularly when you need to cancel operations.
Here's how to safely implement cancellation in C#.
The key to proper cancellation is the CancellationTokenSource class. This provides a token that can be passed to async methods and monitored for cancellation requests.
CancellationTokenSource
// Create a cancellation source with timeout var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10)); var token = cts.Token; try { // Pass token to async operations await DoLongRunningTaskAsync(token); } catch (OperationCanceledException) { // Handle cancellation gracefully Console.WriteLine("Operation was canceled"); } finally { // Always dispose the CancellationTokenSource cts.Dispose(); }
When writing cancellable async methods, check for cancellation at appropriate points:
async Task DoLongRunningTaskAsync(CancellationToken token) { // Check before starting expensive work token.ThrowIfCancellationRequested(); for (int i = 0; i < 100; i++) { // Periodically check during loops if (token.IsCancellationRequested) { // Clean up resources if needed CleanupResources(); // Then throw the standard exception throw new OperationCanceledException(token); } await Task.Delay(100, token); // Built-in methods accept tokens } }
token.ThrowIfCancellationRequested()
OperationCanceledException
By following these patterns, you can ensure your async operations respond promptly to cancellation requests while maintaining clean, resource-efficient code.
In C#, you can format an integer with commas (thousands separator) using ToString with a format specifier.
int number = 1234567; string formattedNumber = number.ToString("N0"); // "1,234,567" Console.WriteLine(formattedNumber);
Explanation:
"N0": The "N" format specifier stands for Number, and "0" means no decimal places. The output depends on the culture settings, so in regions where , is the decimal separator, you might get 1.234.567.
Alternative:
You can also specify culture explicitly if you need a specific format:
using System.Globalization; int number = 1234567; string formattedNumber = number.ToString("N0", CultureInfo.InvariantCulture); Console.WriteLine(formattedNumber); // "1,234,567"
Storing passwords as plain text is dangerous. Instead, you should hash them using a strong, slow hashing algorithm like BCrypt, which includes built-in salting and resistance to brute-force attacks.
Step 1: Install BCrypt NuGet Package
Before using BCrypt, install the BCrypt.Net-Next package:
dotnet add package BCrypt.Net-Next
or via NuGet Package Manager:
Install-Package BCrypt.Net-Next
Step 2: Hash a Password
Use BCrypt.HashPassword() to securely hash a password before storing it:
using BCrypt.Net; string password = "mySecurePassword123"; string hashedPassword = BCrypt.HashPassword(password); Console.WriteLine(hashedPassword); // Output: $2a$12$...
Step 3: Verify a Password
To check a user's login attempt, use BCrypt.Verify():
bool isMatch = BCrypt.Verify("mySecurePassword123", hashedPassword); Console.WriteLine(isMatch); // Output: True
Ensuring proper hashing should be at the top of your list when it comes to building authentication systems.
String interpolation, introduced in C# 6.0, provides a more readable and concise way to format strings compared to traditional concatenation (+) or string.Format(). Instead of manually inserting variables or placeholders, you can use the $ symbol before a string to directly embed expressions inside brackets.
string name = "Walt"; string job = 'Software Engineer'; string message = $"Hello, my name is {name} and I am a {job}"; Console.WriteLine(message);
This would produce the final output of:
Hello, my name is Walt and I am a Software Engineer
String interpolation can also be chained together into a multiline string (@) for even cleaner more concise results:
string name = "Walt"; string html = $@" <div> <h1>Welcome, {name}!</h1> </div>";
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