NET 4.0 implementation of .NET4.5 Task class similar functionality components under .

NET 4.0: TaskExCum Component Explained

introductory

NET technology, the asynchronous programming model is becoming one of the standard practices in modern application development. NET 4.5 introduced theTask classes, greatly simplifying the process of asynchronous programming. However, many legacy systems are still using .NET 4.0 or lower, which do not directly support theTask the full functionality of the class. For this purpose, we have developed theTaskExCum component for .NET 4.0 that is intended to be similar to the .Task Functions, including() cap (a poem)() Methods.

Component Overview

TaskExCum is a static class that provides the following main functionality:

Run method: used to execute the task asynchronously and get the result of the task.
WhenAll Method: Used to wait for multiple tasks to complete and collect the results of all tasks.

Implementation steps

Next, we will explain in detailTaskExCum component implementation steps so that readers can better understand how it works and apply it to their own projects.

Step 1: Create`TaskExCum` resemble

First, we need to create a static classTaskExCumand define static methods in it.

public static class TaskExCum
{
    // Method definitions will be added in subsequent steps
}

Step 2: Realization`Run` methodologies

Run method allows the developer to execute the task asynchronously and get the result of the task. We have created a new method for theRun method provides two forms of overloading for performing operations without return values (Action) and operations with return values (Func<TResult>）。

public static Task<TResult> Run<TResult>(Func<TResult> function)
{
#NET45
    // If the target framework is .NET 4.5 or later, use the method
    return (function);
#NET 4.5 or later, use the method
    // If the target framework is .NET 4.0, use the method
    return (
        NET 4.0, use the method return (function); #else // If the target framework is .
        NET 4.0
        ,

    );
#endif
}

public static Task Run(Action action)
{
#if NET45
    // If the target framework is .NET 4.5 or later, use the method
    return (action); #if NET45 // If the target framework is .NET 4.5 or later, use the
return (action); #else
    // If the target framework is .NET 4.0, use the method
    return (
        NET 4.0, use the method return (action, ); #else // If the target framework is .
        NET 4.0
        ,

    );
#endif
}

elaborate：

conditional compilation: Use#if NET45 compilation symbols, when the target framework of the project is .NET 4.5 and higher, use the Methods.
NET 4.0: When the project target framework is . method to start the task.
- : Indicates that there is no cancel token and the task will not be externally canceled.
- : Indicates that there are no special task creation options.
- : This is one of the key points. Indicates that the default thread pool scheduler is used, which means that tasks are executed on a thread in the thread pool rather than starting a new thread each time. This helps improve performance and resource utilization.

Step 3: Realization`WhenAll` methodologies

WhenAll method is used to wait for multiple tasks to complete and collect the results of all of them. We have created a new method for theWhenAll method provides several forms of overloading to support different types of task collections.

public static Task<TResult[]> WhenAll<TResult>(IEnumerable<Task<TResult>> tasks)
{
#if NET45
    // If the target framework is .NET 4.5 or later, use the method
    return (tasks);
#NET 4.5 or later, use the method
    // If the target framework is .NET 4.0, call the WhenAllCore method
    return WhenAllCore(tasks); #else // If the target framework is .
#endif
}

public static Task<TResult[]> WhenAll<TResult>(params Task<TResult>[] tasks)
{
#if NET45
    // If the target framework is .NET 4.5 or later, use the method
    return (tasks);
#NET 4.5 or later, use the method
    // If the target framework is .NET 4.0, call the WhenAllCore method
    return WhenAllCore(tasks); #else // If the target framework is .
#endif
}

public static Task WhenAll(IEnumerable<Task> tasks)
{
#endif NET45
    // If the target framework is .NET 4.5 or later, use the method
    return (tasks); #if NET45 // If the target framework is .NET 4.5 or later, use the
#NET 4.5 or later, use the method
    // If the target framework is .NET 4.0, call the WhenAllCore method
    return WhenAllCore(tasks); #else // If the target framework is .
#endif
}

elaborate：

conditional compilation: Use#if NET45 compilation symbols, when the target framework of the project is .NET 4.5 and higher, use the Methods.
WhenAllCoreNET 4.0: When the project target framework is .WhenAllCore method to achieve the same functionality.

Step 4: Realization`WhenAllCore` methodologies

WhenAllCore The methodology isWhenAll The core implementation of the method that handles the collection of tasks, waits for all tasks to complete, and collects results or exception information.

private static Task WhenAllCore(IEnumerable<Task> tasks)
{
    return WhenAllCore(tasks, (completedTasks, tcs) => (null));
}

private static Task<TResult[]> WhenAllCore<TResult>(IEnumerable<Task<TResult>> tasks)
{
    return WhenAllCore(<Task>(), (completedTasks, tcs) =>
    {
        ((t => ((Task<TResult>)t).Result).ToArray());
    });
}

private static Task<TResult> WhenAllCore<TResult>(IEnumerable<Task> tasks, Action<Task[], TaskCompletionSource<TResult>> setResultAction)
{
    if (tasks == null)
    {
        throw new ArgumentNullException("tasks");
    }

    ();
    (setResultAction != null);

    var tcs = new TaskCompletionSource<TResult>();
    var array = (tasks as Task[]) ?? ();

    if ( == 0)
    {
        // If the task collection is empty，Setting results directly
        setResultAction(array, tcs);
    }
    else
    {
        (array, completedTasks =>
        {
            var exceptions = new List<Exception>();
            bool hasCanceled = false;

            foreach (var task in completedTasks)
            {
                if ()
                {
                    // Gather anomaly information for all failed missions
                    ();
                }
                else if ()
                {
                    // Check if a task has been canceled
                    hasCanceled = true;
                }
            }

            if ( > 0)
            {
                // If there is an anomaly，Setting Exception Results
                (exceptions);
            }
            else if (hasCanceled)
            {
                // If a task is canceled，Setting up canceled results
                ();
            }
            else
            {
                // If there are no exceptions and no tasks are canceled，Setting Successful Results
                setResultAction(completedTasks, tcs);
            }
        }, , , );
    }

    return ;
}

elaborate：

parameter verification: Check if the incoming task collection isnull, and if so, throws theArgumentNullException。
TaskCompletionSource: Create aTaskCompletionSource object to manage the completion status of the task.
Task switching: Converts a collection of tasks into an array for subsequent processing.
Number of tasks checked: If the set of tasks is empty, it is straightforward to call thesetResultAction Setting results.
Waiting for all tasks to be completed: Use method waits for all tasks to complete.
- Exception handling: Traverses completed tasks and collects exception information for all failed tasks.
- deprocessing: Check to see if any tasks have been canceled.
- Setting results: If there are no exceptions and no tasks have been canceled, calling thesetResultAction Setting results.
- : Here again, use the, ensuring that tasks are executed in the default thread pool rather than starting a new thread each time.

Step 5: Add Exception Handling Logic

In order to ensure the robustness of the component, we also need to add a new component to theWhenAllCore method to add exception handling logic to ensure that all exceptions are caught and handled correctly.

private static void AddPotentiallyUnwrappedExceptions(ref List<Exception> targetList, Exception exception)
{
    var ex = exception as AggregateException;
    (exception != null);
    (ex == null || > 0);

    if (targetList == null)
    {
        targetList = new List<Exception>();
    }

    if (ex != null)
    {
        // If the exception is AggregateException，Add its internal exception
        ( == 1 ? [0] : ex);
    }
    else
    {
        // if not，Add exceptions directly
        (exception);
    }
}

elaborate：

Exception type checking: Check if the incoming exception isAggregateException。
Exception List Initialization: IftargetList because ofnull, then a new list is initialized.
Exceptions added: Add an exception or its internal exception to the list, depending on the type of the exception.

sample code (computing)

To help readers better understand how to useTaskExCum component, here is some sample code.

Example 1: Using`Run` methodologies

using System;
using ;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            // Execute tasks asynchronously and wait for results
            string result = (() => "Hello from Task!").Result;
            (result);
        }
        catch (Exception ex)
        {
            ($"Error: {}");
        }
    }
}

Example 2: Using`WhenAll` methodologies

using System;
using ;
using ;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            // Creating multiple tasks
            var tasks = (1, 5).Select(i => (() => i * i)).ToArray();
            
            // Wait for all tasks to complete and get results
            int[] results = (tasks).Result;
            
            // output result
            foreach (var result in results)
            {
                (result);
            }
        }
        catch (Exception ex)
        {
            ($"Error: {}");
        }
    }
}

reach a verdict

pass (a bill or inspection etc)TaskExCum NET 4.0, we can enjoy the convenience of the modern asynchronous programming model even in older framework versions like . We hope that this component will help developers who need to implement asynchronous operations in older versions of the .NET framework to improve their productivity and code quality. If you have any suggestions or improvements, feel free to leave a comment!

For more details, please see:/Bob-luo/p/18515670
The above is a brief description of theTaskExCum component in detail. We hope that through this article, readers will be able to better understand and use this component to achieve efficient asynchronous programming in their own projects. If you have any questions or need further help, please feel free to leave a comment!

NET 4.0 implementation of .NET4.5 Task class similar functionality components under .

introductory

Component Overview

Implementation steps

Step 1: CreateTaskExCum resemble

Step 2: RealizationRun methodologies

Step 3: RealizationWhenAll methodologies

Step 4: RealizationWhenAllCore methodologies

Step 5: Add Exception Handling Logic

sample code (computing)

Example 1: UsingRun methodologies

Example 2: UsingWhenAll methodologies

reach a verdict

Step 1: Create`TaskExCum` resemble

Step 2: Realization`Run` methodologies

Step 3: Realization`WhenAll` methodologies

Step 4: Realization`WhenAllCore` methodologies

Example 1: Using`Run` methodologies

Example 2: Using`WhenAll` methodologies