国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Table of Contents
Implement progress bar when downloading files using HttpClient
Introduction
Extension method implementation
Home Backend Development C++ How to Implement a Progress Bar with HttpClient During File Downloads?

How to Implement a Progress Bar with HttpClient During File Downloads?

Jan 12, 2025 pm 06:46 PM

How to Implement a Progress Bar with HttpClient During File Downloads?

Implement progress bar when downloading files using HttpClient

Introduction

This article describes how to use HttpClient to implement a progress bar when downloading files. Since DownloadOperation cannot be used due to certificate handling limitations, another approach is required.

Use IProgress

Starting in .Net 4.5, IProgress allows asynchronous progress reporting. Here's an example of how to integrate it with HttpClient for file downloading:

// Set up HttpClient using (var client = new HttpClient()) {

// 帶進度報告的文件下載
await client.DownloadAsync(DownloadUrl, file, progress, cancellationToken);

}

Extension method implementation

The DownloadAsync extension method depends on another extension method for stream replication with progress reporting:

public static async Task DownloadAsync(this HttpClient client, string requestUri, Stream destination, IProgress<float> progress = null, CancellationToken cancellationToken = default) {

    // 獲取內(nèi)容長度的標(biāo)頭
    using (var response = await client.GetAsync(requestUri, HttpCompletionOption.ResponseHeadersRead)) {
        // 如果不支持,則忽略進度報告
        if (progress == null || !response.Content.Headers.ContentLength.HasValue) {
            await response.Content.ReadAsStreamAsync(cancellationToken).CopyToAsync(destination);
            return;
        }

        // 計算相對進度
        var relativeProgress = new Progress<long>(totalBytes => progress.Report((float)totalBytes / response.Content.Headers.ContentLength.Value));
        // 帶進度報告的下載
        await response.Content.ReadAsStreamAsync().CopyToAsync(destination, 81920, relativeProgress, cancellationToken);
        progress.Report(1);
    }
}

public static async Task CopyToAsync(this Stream source, Stream destination, int bufferSize, IProgress<long> progress = null, CancellationToken cancellationToken = default) {

    var buffer = new byte[bufferSize];
    long totalBytesRead = 0;
    int bytesRead;
    while ((bytesRead = await source.ReadAsync(buffer, 0, buffer.Length, cancellationToken).ConfigureAwait(false)) != 0) {
        await destination.WriteAsync(buffer, 0, bytesRead, cancellationToken).ConfigureAwait(false);
        totalBytesRead += bytesRead;
        progress?.Report(totalBytesRead);
    }
}
<code>

通過以上代碼,開發(fā)者可以輕松地在使用HttpClient下載文件的同時,實現(xiàn)進度條功能,提升用戶體驗。  需要注意的是,`CopyToAsync` 方法中的 `bufferSize` 參數(shù)可以根據(jù)實際情況調(diào)整,以平衡性能和內(nèi)存消耗。</code>

The above is the detailed content of How to Implement a Progress Bar with HttpClient During File Downloads?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

C   Polymorphism: Enhancing Code Reusability and Flexibility C Polymorphism: Enhancing Code Reusability and Flexibility Jun 10, 2025 am 12:04 AM

Polymorphism in C is implemented through virtual functions and abstract classes, enhancing the reusability and flexibility of the code. 1) Virtual functions allow derived classes to override base class methods, 2) Abstract classes define interfaces, and force derived classes to implement certain methods. This mechanism makes the code more flexible and scalable, but attention should be paid to its possible increase in runtime overhead and code complexity.

C   Polymorphism : is function overloading a kind of polymorphism? C Polymorphism : is function overloading a kind of polymorphism? Jun 20, 2025 am 12:05 AM

Yes, function overloading is a polymorphic form in C, specifically compile-time polymorphism. 1. Function overload allows multiple functions with the same name but different parameter lists. 2. The compiler decides which function to call at compile time based on the provided parameters. 3. Unlike runtime polymorphism, function overloading has no extra overhead at runtime, and is simple to implement but less flexible.

C   Destructors code samples C Destructors code samples Jun 13, 2025 am 12:04 AM

The destructor in C is used to free the resources occupied by the object. 1) They are automatically called at the end of the object's life cycle, such as leaving scope or using delete. 2) Resource management, exception security and performance optimization should be considered during design. 3) Avoid throwing exceptions in the destructor and use RAII mode to ensure resource release. 4) Define a virtual destructor in the base class to ensure that the derived class objects are properly destroyed. 5) Performance optimization can be achieved through object pools or smart pointers. 6) Keep the destructor thread safe and concise, and focus on resource release.

What Are the Different Kinds of Polymorphism in C  ? Explained What Are the Different Kinds of Polymorphism in C ? Explained Jun 20, 2025 am 12:08 AM

C has two main polymorphic types: compile-time polymorphism and run-time polymorphism. 1. Compilation-time polymorphism is implemented through function overloading and templates, providing high efficiency but may lead to code bloating. 2. Runtime polymorphism is implemented through virtual functions and inheritance, providing flexibility but performance overhead.

How to Implement Polymorphism in C  : A Step-by-Step Tutorial How to Implement Polymorphism in C : A Step-by-Step Tutorial Jun 14, 2025 am 12:02 AM

Implementing polymorphism in C can be achieved through the following steps: 1) use inheritance and virtual functions, 2) define a base class containing virtual functions, 3) rewrite these virtual functions by derived classes, and 4) call these functions using base class pointers or references. Polymorphism allows different types of objects to be treated as objects of the same basis type, thereby improving code flexibility and maintainability.

C  : Is Polymorphism really useful? C : Is Polymorphism really useful? Jun 20, 2025 am 12:01 AM

Yes, polymorphisms in C are very useful. 1) It provides flexibility to allow easy addition of new types; 2) promotes code reuse and reduces duplication; 3) simplifies maintenance, making the code easier to expand and adapt to changes. Despite performance and memory management challenges, its advantages are particularly significant in complex systems.

C   Destructors: Common Errors C Destructors: Common Errors Jun 20, 2025 am 12:12 AM

C destructorscanleadtoseveralcommonerrors.Toavoidthem:1)Preventdoubledeletionbysettingpointerstonullptrorusingsmartpointers.2)Handleexceptionsindestructorsbycatchingandloggingthem.3)Usevirtualdestructorsinbaseclassesforproperpolymorphicdestruction.4

Polymorphism in C  : A Comprehensive Guide with Examples Polymorphism in C : A Comprehensive Guide with Examples Jun 21, 2025 am 12:11 AM

Polymorphisms in C are divided into runtime polymorphisms and compile-time polymorphisms. 1. Runtime polymorphism is implemented through virtual functions, allowing the correct method to be called dynamically at runtime. 2. Compilation-time polymorphism is implemented through function overloading and templates, providing higher performance and flexibility.

See all articles