[英]What is the best approach/practice for awaiting multiple independent tasks?
var contractSchemaTask = contractSchemaRepository.GetByContractIdAsync(data.Id);
var sectionsTask = sectionRepository.GetAllByContractIdAsync(id);
var latestContractIdTask = contractRepository
.GetLatestContractIdByFolderIdAsync(data.FolderId.Value);
List<Task> allTasks = new List<Task>()
{ contractSchemaTask, sectionsTask, latestContractIdTask };
while (allTasks.Any())
{
Task finished = await Task.WhenAny(allTasks);
if (finished == contractSchemaTask)
{
var contractSchema = await contractSchemaTask;
result.ReturnData.IsSchedules = contractSchema.Count > 0 ? true : false;
}
else if (finished == sectionsTask)
{
List<Section> sections = await sectionsTask;
List<TextValueVM> SectionTabList = sections.Count > 0 ? sections
.OrderBy(a => a.SectionNumber)
.Select(a => new TextValueVM()
{ Text = a.ToString(), Value = a.Id.ToString() })
.ToList() : new List<TextValueVM>();
bool IsSectionsLinked = false;
int linkSectionCount = sections
.Where(x => x.LinkSectionId != null && x.LinkSectionId != Guid.Empty)
.ToList()
.Count();
if (linkSectionCount == 0 && sections.Count > 0)
{
List<Guid> sectionIds = sections.Select(x => x.Id.Value).ToList();
List<Section> currentContractLinkSections = await sectionRepository
.GetSectionsByLinkSectionIdAsync(sectionIds);
if (currentContractLinkSections.Count > 0)
{
IsSectionsLinked = true;
}
}
else if (linkSectionCount > 0)
{
IsSectionsLinked = true;
}
result.ReturnData.SectionTabList = SectionTabList;
result.ReturnData.IsSectionsLinked = IsSectionsLinked;
}
else if (finished == latestContractIdTask)
{
Guid LatestContractId = await latestContractIdTask;
result.ReturnData.isLatestContract
= (data.Id == LatestContractId) ? true : false;
}
allTasks.Remove(finished);
}
我正在開發一個 asp.net core 3.0 WebAPI 項目。 以上是我使用 while 循環處理的獨立任務的示例代碼。 在異步編程中是否有更好或有效的方法來處理獨立任務?
PS:所有 3 個任務都是獨立的,它們的響應時間可能會有所不同,具體取決於從數據庫中提取的記錄數。
你應該這樣做:
public Task Main()
{
var result = new Result();
return Task.WhenAll(TaskOne(result), TaskTwo(result), TaskThree(result));
}
private async Task TaskOne(Result result)
{
var contractSchema = await contractSchemaRepository.GetByContractIdAsync(data.Id);
//your logic for task1, set related result properties
}
private async Task TaskTwo(Result result)
{
var sections = await sectionRepository.GetAllByContractIdAsync(id);
//your logic for task2, set related result properties
}
private async Task TaskThree(Result result)
{
var latestContractId = await contractRepository.GetLatestContractIdByFolderIdAsync(data.FolderId.Value);
//your logic for Task3, set related result properties
}
Result
類應該實現為線程安全的,因為任務可以同時執行。 如果你只是在每個方法中設置不同的屬性應該沒問題。
將 Task.WhenAll 與 Continue 結合使用,您可以在任務完成后立即執行代碼,而無需等待其余任務。
class Test {
public static async Task Main() {
var t1 = AsyncWork1().ContinueWith((t) => Console.WriteLine($"Task1 finished with value {t.Result}"));
var t2 = AsyncWork2().ContinueWith((t) => Console.WriteLine($"Task2 finished with value {t.Result}"));
var t3 = AsyncWork3().ContinueWith((t) => Console.WriteLine($"Task3 finished with value {t.Result}"));
await Task.WhenAll(new[] { t1, t2, t3 });
//here we know that all tasks has been finished and its result behaviour executed.
Console.ReadKey();
}//main
public static async Task<int> AsyncWork1() {
await Task.Delay(1000);
return 1;
}
public static async Task<string> AsyncWork2() {
await Task.Delay(100);
return "work2";
}
public static async Task<bool> AsyncWork3() {
await Task.Delay(500);
return true;
}
}//class Test
與此比較:
class Test {
public static async Task Main() {
var t1 = AsyncWork1();
var t2 = AsyncWork2();
var t3 = AsyncWork3();
await Task.WhenAll(new[] { t1, t2, t3 });
//all task finished but now we have to execute the result behaviour in a sync way
Console.WriteLine($"Task1 finished with value {t1.Result}");
Console.WriteLine($"Task2 finished with value {t2.Result}");
Console.WriteLine($"Task3 finished with value {t3.Result}");
Console.ReadKey();
}//main
public static async Task<int> AsyncWork1() {
await Task.Delay(1000);
return 1;
}
public static async Task<string> AsyncWork2() {
await Task.Delay(100);
return "work2";
}
public static async Task<bool> AsyncWork3() {
await Task.Delay(500);
return true;
}
}//class Test
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