SoFunction
Updated on 2025-03-06

C# and .NET to generate and use asynchronous streaming methods

In software development, it often takes a long time to handle I/O-intensive tasks, such as file reading and writing, network requests, etc. These waiting times can cause slow application response and affect user experience. In order to solve this problem, asynchronous programming came into being. C# is a language that supports asynchronous programming, and the .NET framework provides a rich asynchronous programming model. This article will explain how to generate and use asynchronous streams using C# and .NET.

1. Introduction to asynchronous programming

Asynchronous programming is a programming paradigm that allows programs to perform other tasks while waiting for an operation to complete. This improves application responsiveness and performance, especially when dealing with I/O-intensive tasks.
Asynchronous programming in C# mainly relies on the async and await keywords. The async keyword is used to declare an asynchronous method, while the await keyword is used to wait for an asynchronous operation to complete. These two keywords together form the asynchronous programming model of C#.

1.1 Creating an asynchronous method

To create an asynchronous method in C#, you need to add the async keyword before the method signature. This way, the compiler will know that the method contains asynchronous operations and handles it appropriately when invoked.

public async Task MyAsyncMethod()
{
    // Asynchronous operation}

1.2 Using the await keyword

The await keyword is used to wait for an asynchronous operation to complete. In the await expression, you can specify a variable of type Task to indicate the operation to be waited for. When the await expression is executed, the current task will be suspended until the waiting operation is completed.

public async Task MyAsyncMethod()
{
string result = await GetSomeAsyncOperation();
// Use results}
public async Task GetSomeAsyncOperation()
{
// Asynchronous operationreturn “result”;
}

2. Asynchronous flow

.NET 5 and later introduces Async Streams, a new asynchronous I/O model that simplifies reading, writing, and processing of asynchronous files. Asynchronous streams are especially suitable for situations where large amounts of data are required, such as reading large files or traversing large numbers of lines.

2.1 Creating an asynchronous stream

To create an asynchronous stream, you can use the AsyncStreamReader and AsyncStreamWriter classes in the namespace. These two classes are used to read and write asynchronous streams respectively.

using ;
// Create an asynchronous stream readervar reader = new AsyncStreamReader("");
// Create an asynchronous stream writervar writer = new AsyncStreamWriter("");

2.2 Read data using asynchronous streams

The asynchronous stream reader provides the ReadLineAsync method for asynchronously reading a row of data.

string line;
while ((line = await ()) != null)
{
    (line);
}

2.3 Using asynchronous streams to write data

The asynchronous stream writer provides the WriteLineAsync method for writing a row of data asynchronously.

await ("Hello, World!");

2.4 Handling exceptions

When using asynchronous streams, you may encounter various exceptions, such as the file does not exist, insufficient permissions, etc. Therefore, these exceptions need to be handled correctly to ensure the stability and reliability of the program.

try
{
    // Asynchronous operation}
catch (Exception ex)
{
    // Handle exceptions}

3. Use asynchronous streams for data processing

In .NET, asynchronous streams can be used to read files, write files, and process data. Below we will use an example to demonstrate how to use asynchronous streams for data processing.

3.1 Example: Asynchronous stream reads file contents

First, we need to create a simple C# program that uses asynchronous streams to read the file contents.

using System;
using ;
using ;

class Program
{
    static async Task Main(string[] args)
    {
        // Define the file path to read        string filePath = "";

        // Use asynchronous stream to read file content        try
        {
            // Use the await keyword to wait for the asynchronous operation to complete            string content = await (filePath);
            (content);
        }
        catch (Exception ex)
        {
            // Handle possible exceptions            ("An error occurred: " + );
        }
    }
}

In the above code, we use the method to read the file content, which is an asynchronous operation. The await keyword is used to wait for the asynchronous operation to complete, and release control during the wait, giving up the CPU to use for other tasks.

3.2 Example: Asynchronous stream writes file contents

Next, we demonstrate how to use an asynchronous stream to write file contents with an example.

using System;
using ;
using ;
class Program
{
    static async Task Main(string[] args)
    {
        // Define the file path to write        string filePath = "";
        // Write file content using asynchronous stream        try
        {
            // Use the await keyword to wait for the asynchronous operation to complete            await (filePath, "Hello, World!");
            ("File writing successfully");
        }
        catch (Exception ex)
        {
            // Handle possible exceptions            ("An error occurred: " + );
        }
    }
}

In this example, we use the method to write the file content, which is also an asynchronous operation. The await keyword is used to wait for the asynchronous operation to complete.

4. Optimize the performance of asynchronous flows

Asynchronous streams provide many features for optimizing performance. For example, you can use CancellationToken to cancel asynchronous operations, or use the asynchronous versions of StreamReader and StreamWriter to read and write files.

Example: CancellationToken cancels asynchronous operations

The following is an example of using CancellationToken to cancel asynchronous operations.

using System;
using ;
using ;
using ;

class Program
{
    static async Task Main(string[] args)
    {
        // Define the file path to read        string filePath = "";
        CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();

        // Use asynchronous stream to read file content        try
        {
            // Create a task that cancels the operation when the user presses Ctrl+C             += (sender, eventArgs) =>
            {
                 = true; // Block the program from exiting                (); // Cancel asynchronous operation            };

            string content = await (filePath, );
            (content);
        }
        catch (OperationCanceledException)
        {
            // Handle cancel operation            ("The operation was cancelled");
        }
        catch (Exception ex)
        {
            // Handle other exceptions            ("An error occurred: " + );
        }
    }
}

In this example, we used CancellationTokenSource to create an asynchronous operation that can be cancelled. When the user presses Ctrl+C, the event triggers, thus canceling the asynchronous operation.

5. Framework and libraries that support asynchronous operations

.NET provides a variety of frameworks and libraries to support asynchronous operations, such as:

1.: Provides Task class and related asynchronous programming models.
2.: Provides related classes for asynchronous stream reading and writing.
3.: Asynchronous HTTP is provided
The requested class. 4.: Provides a class for asynchronous SQL database operations.

6. Practical application scenarios

Asynchronous streams have wide applications in many fields, and the following are some examples:

  • Web Development:In Core, asynchronous streams can be used to handle asynchronous HTTP requests and improve the response speed of web applications.
  • Data processing:When processing large data sets, asynchronous streams can improve the efficiency of data reading and writing and reduce I/O waiting time.
  • File upload and download:In the file upload and download operation, asynchronous streaming can increase the speed of file transfer and allow users to perform other operations during the transfer process.
  • Database operations:Asynchronous SQL operations can improve the performance of database queries and transaction processing and reduce application response time.

Summarize

This article describes how to generate and use asynchronous streams using C# and .NET. By using the async and await keywords, it is easy to create asynchronous methods and handle I/O-intensive tasks. In addition, asynchronous streams provide a cleaner and efficient asynchronous I/O programming model suitable for handling large amounts of data. Mastering this knowledge can help developers write more efficient and responsive applications.

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