[英]ASP.NET Core with - Refresh UI with SignalR when certain changes are made to the DB
我有一個通知面板,它本身保存與當前用戶相關的通知。 我正在努力理解集線器和客戶端腳本一起執行的整個概念。 我想刷新使用 SignalR 接收通知的用戶的 UI。
集線器 class
public class NotificationHub : Hub
{
private readonly ApplicationDbContext dbContext;
public NotificationHub(ApplicationDbContext dbContext)
{
this.dbContext = dbContext;
}
public override Task OnConnectedAsync()
{
base.OnConnectedAsync();
var user = this.Context.User.Identity.Name;
// Groups.AddAsync(Context.ConnectionId, user);
return Task.CompletedTask;
}
}
配置:
services.AddSignalR();
services.AddSingleton(typeof(IUserIdProvider), typeof(MyUserIdProvider));
路線
app.UseEndpoints(
endpoints =>
{
endpoints.MapControllerRoute("areaRoute", "{area:exists}/{controller=Home}/{action=Index}/{id?}");
endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}/{id?}");
endpoints.MapRazorPages();
endpoints.MapHub<NotificationHub>("/notificationHub");
});
這是向 Dogsitter 用戶發送通知的 controller,這里我想刷新 Dogsitter 的通知 UI:
[HttpPost]
public async Task<IActionResult> SendRequestToDogsitter([FromForm]string id, SendNotificationInputModel inputModel)
{
var user = await this.userManager.GetUserAsync(this.User);
var owner = user.Owners.FirstOrDefault();
var dogsitter = this.dogsitterService.GetDogsitterByDogsitterId(id);
await this.ownerService.SendNotification(id, owner, inputModel.Date, inputModel.StartTime, inputModel.EndTime);
// Refresh the page to reflect changes.
await this.notificationHubContext.Clients.User(user.UserName).SendAsync("refreshUI");
// Notify the user who is receiving the notification. (if connected)
await this.notificationHubContext.Clients.User(owner.User.UserName).SendAsync("sendNotification", dogsitter.User.UserName);
return this.RedirectToAction("FindDogsitter");
}
由於我的通知面板存在於布局頁面中呈現的部分視圖中,因此我將腳本放在布局頁面本身中:
<script>
var notificationConnection;
openConnection();
function openConnection() {
notificationConnection = new signalR.HubConnection("/notificationHub");
notificationConnection
.start()
.catch(() => {
alert("Error while establishing connection");
});
}
notificationConnection.on("SendNotification", (user) => {
});
friendConnection.on("refreshUI", (user) => {
});
</script>
最后是我在這篇文章之后更改的 MyUserIdProvider: https://docs.microsoft.com/en-us/archive/msdn-magazine/2018/august/cutting-edge-social-style-notifications-with-asp-net -核心信號
public class MyUserIdProvider : IUserIdProvider
{
public string GetUserId(HubConnectionContext connection)
{
return connection.User.Identity.Name;
}
}
基本上,當用戶由於某些操作而必須通知另一個用戶時,我希望服務器監聽 function 調用 refreshUI,它將刷新目標用戶 UI。我真的不知道如何開始使用客戶端部分。 非常感謝任何幫助。
您只需要一個連接到 signalR 的服務、集線器上已有的通知面板、客戶端連接時獲取所有通知的方法和廣播方法,例如:
在您的集線器上,當客戶端連接時,您應該收到所有通知:
public async Task<OperationResult> GetNotificationsAsync(Groups groups)
{
try
{
IList<OutgoingNotification> notifications = await this.NotificationsManager.GetNotificationsForThisClientAsync(groups).ConfigureAwait(false);
if (notifications.Count != 0)
{
// Send the notifications
for (int i = 0; i < notifications.Count; i++)
{
await this.BroadcastNotificationToCallerAsync(notifications[i]).ConfigureAwait(false);
}
}
return OperationResult.Success();
}
catch (ArgumentNullException)
{
throw new ServiceException(ServiceExceptionCode.NoDataProvidedToGetNotifications, Resources.RES_No_Data_Provided_To_Get_Notifications);
}
}
在客戶端:
private async getNotifications(groups: ISignalRGroups) {
await this.hubMessageConnection.invoke("GetNotificationsAsync", groups)
.then(() => {
this.onGetNotificationsComplete.emit();
})
.catch(() => {
this.onError.emit(WidgetStateEnum.getNotificationError);
});
}
然后,當您想發送通知時,只需通過 DI 注入管理器中的集線器即可發送通知,例如:
private IHubContext<NotificationsHub, INotificationsHub> NotificationsHub
{
get
{
return this.serviceProvider.GetRequiredService<IHubContext<NotificationsHub, INotificationsHub>>();
}
}
public async Task SendNotificationToGroupAsync(OutgoingNotification outcomingNotification)
{
await this.NotificationsHub.Clients.Group(outcomingNotification.Target).Message(outcomingNotification).ConfigureAwait(false);
}
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