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.
When working with URLs in C#, encoding is essential to ensure that special characters (like spaces, ?, &, and =) don’t break the URL structure. The recommended way to encode a string for a URL is by using Uri.EscapeDataString(), which converts unsafe characters into their percent-encoded equivalents.
string rawText = "hello world!"; string encodedText = Uri.EscapeDataString(rawText); Console.WriteLine(encodedText); // Output: hello%20world%21
This method encodes spaces as %20, making it ideal for query parameters.
For ASP.NET applications, you can also use HttpUtility.UrlEncode() (from System.Web), which encodes spaces as +:
using System.Web; string encodedText = HttpUtility.UrlEncode("hello world!"); Console.WriteLine(encodedText); // Output: hello+world%21
For .NET Core and later, Uri.EscapeDataString() is the preferred choice.
Raw string literals in C# provide a flexible way to work with multiline strings, with some interesting rules around how quotes work.
The key insight is that you can use any number of double quotes (three or more) to delimit your string, as long as the opening and closing sequences have the same number of quotes.
"""
// Three quotes - most common usage string basic = """ This is a basic multiline string """; // Four quotes - when your content has three quotes string withThreeQuotes = """" Here's some text with """quoted""" content """"; // Five quotes - when your content has four quotes string withFourQuotes = """"" Here's text with """"nested"""" quotes """""; // Six quotes - for even more complex scenarios string withFiveQuotes = """""" Look at these """""nested""""" quotes! """""";
The general rule is that if your string content contains N consecutive double quotes, you need to wrap the entire string with at least N+1 quotes. This ensures the compiler can properly distinguish between your content and the string's delimiters.
// Example demonstrating the N+1 rule string example1 = """ No quotes inside """; // 3 quotes is fine string example2 = """" Contains """three quotes""" """"; // Needs 4 quotes (3+1) string example3 = """"" Has """"four quotes"""" """""; // Needs 5 quotes (4+1)
// Indentation example string properlyIndented = """ { "property": "value", "nested": { "deeper": "content" } } """; // This line's position determines the indentation
This flexibility with quote counts makes raw string literals extremely versatile, especially when dealing with content that itself contains quotes, like JSON, XML, or other structured text formats.
Slow initial load times can drive users away from your React application. One powerful technique to improve performance is lazy loading - loading components only when they're needed.
Let's explore how to implement this in React.
By default, React bundles all your components together, forcing users to download everything upfront. This makes navigation much quicker and more streamlined once this initial download is complete.
However, depending on the size of your application, it could also create a long initial load time.
import HeavyComponent from './HeavyComponent'; import AnotherHeavyComponent from './AnotherHeavyComponent'; function App() { return ( <div> {/* These components load even if user never sees them */} <HeavyComponent /> <AnotherHeavyComponent /> </div> ); }
React.lazy() lets you defer loading components until they're actually needed:
import React, { lazy, Suspense } from 'react'; // Components are now loaded only when rendered const HeavyComponent = lazy(() => import('./HeavyComponent')); const AnotherHeavyComponent = lazy(() => import('./AnotherHeavyComponent')); function App() { return ( <div> <Suspense fallback={<div>Loading...</div>}> <HeavyComponent /> <AnotherHeavyComponent /> </Suspense> </div> ); }
Combine with React Router for even better performance:
import React, { lazy, Suspense } from 'react'; import { BrowserRouter, Routes, Route } from 'react-router-dom'; const Home = lazy(() => import('./pages/Home')); const Dashboard = lazy(() => import('./pages/Dashboard')); const Settings = lazy(() => import('./pages/Settings')); function App() { return ( <BrowserRouter> <Suspense fallback={<div>Loading...</div>}> <Routes> <Route path="/" element={<Home />} /> <Route path="/dashboard" element={<Dashboard />} /> <Route path="/settings" element={<Settings />} /> </Routes> </Suspense> </BrowserRouter> ); }
Implement these techniques in your React application today and watch your load times improve dramatically!
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