| 
 | 1 | +---  | 
 | 2 | +title: Reuse One Notification Instance in the App  | 
 | 3 | +description: Learn how to define and use a single Telerik Notification component instance in a Blazor application.  | 
 | 4 | +type: how-to  | 
 | 5 | +page_title: How to Reuse a Single Notification Component Instance in the App  | 
 | 6 | +slug: notification-kb-single-instance  | 
 | 7 | +tags: telerik, blazor, notification  | 
 | 8 | +ticketid: 1627975, 1602587, 1591578, 1579647  | 
 | 9 | +res_type: kb  | 
 | 10 | +---  | 
 | 11 | + | 
 | 12 | +## Environment  | 
 | 13 | + | 
 | 14 | +<table>  | 
 | 15 | +    <tbody>  | 
 | 16 | +        <tr>  | 
 | 17 | +            <td>Product</td>  | 
 | 18 | +            <td>Notification for Blazor</td>  | 
 | 19 | +        </tr>  | 
 | 20 | +    </tbody>  | 
 | 21 | +</table>  | 
 | 22 | + | 
 | 23 | +## Description  | 
 | 24 | + | 
 | 25 | +This KB article answers the following questions:  | 
 | 26 | + | 
 | 27 | +* How to use a single Telerik Notification component for Blazor in multiple other Razor files?  | 
 | 28 | +* How to reuse one Notification instance in the whole Blazor application?  | 
 | 29 | + | 
 | 30 | +## Solution  | 
 | 31 | + | 
 | 32 | +There are two possible ways to implement a reusable Notification component instance:  | 
 | 33 | + | 
 | 34 | +* [Pass the Notification in a Cascading Value](#pass-the-notification-in-a-cascading-value)  | 
 | 35 | +* [Use the Notification as a Service](#use-the-notification-as-a-service)  | 
 | 36 | + | 
 | 37 | +The Notification component in both scenarios must be defined:  | 
 | 38 | + | 
 | 39 | +1. As a descendant (or child) of the [`<TelerikRootComponent>`]({%slug rootcomponent-overview%}).  | 
 | 40 | +1. In a `.razor` file with enabled interactive render mode. The `MainLayout` is interactive only if the Blazor app has **Global** interactivity location.  | 
 | 41 | + | 
 | 42 | +### Pass the Notification in a Cascading Value  | 
 | 43 | + | 
 | 44 | +1. [Define a Telerik Notification component]({%slug notification-overview%}#creating-blazor-notification) in `MainLayout.razor`.  | 
 | 45 | +1. [Set the Notification `@ref` attribute]({%slug notification-overview%}#notifications-reference-and-methods). Use an `internal` or `public` accessor.  | 
 | 46 | +1. Wrap the `@Body` in `MainLayout` in a `<CascadingValue>` that passes the `MainLayout` instance itself. This avoids potential issues with missing Notification instance in child components on initial app load. Set `IsFixed="true"` to the `CascadingValue` to avoid unnecessary renders.  | 
 | 47 | +1. Consume the `MainLayout` instance in child Razor components as a `[CascadingParameter]` and access the Notification instance methods through the `MainLayout` instance.  | 
 | 48 | + | 
 | 49 | +>caption Reuse a Notification as a CascadingValue  | 
 | 50 | +
  | 
 | 51 | +<div class="skip-repl"></div>  | 
 | 52 | + | 
 | 53 | +````MainLayout.razor  | 
 | 54 | +@inherits LayoutComponentBase  | 
 | 55 | +
  | 
 | 56 | +<TelerikRootComponent>  | 
 | 57 | +
  | 
 | 58 | +    <TelerikNotification @ref="@NotificationRef" />  | 
 | 59 | +
  | 
 | 60 | +    <CascadingValue Value="@this" Name="MainLayoutRef" IsFixed="true">  | 
 | 61 | +        @Body  | 
 | 62 | +    </CascadingValue>  | 
 | 63 | +
  | 
 | 64 | +</TelerikRootComponent>  | 
 | 65 | +
  | 
 | 66 | +@code {  | 
 | 67 | +    internal TelerikNotification? NotificationRef { get; set; }  | 
 | 68 | +}  | 
 | 69 | +````  | 
 | 70 | +````_Imports.razor  | 
 | 71 | +@using YourAppName.Components.Layout  | 
 | 72 | +````  | 
 | 73 | +````Home.razor  | 
 | 74 | +@page "/"  | 
 | 75 | +
  | 
 | 76 | +<PageTitle>Home</PageTitle>  | 
 | 77 | +
  | 
 | 78 | +<TelerikButton OnClick="@ShowNotification">Show Notification</TelerikButton>  | 
 | 79 | +
  | 
 | 80 | +<TelerikButton OnClick="@HideNotifications">Hide All Notifications</TelerikButton>  | 
 | 81 | +
  | 
 | 82 | +@code {  | 
 | 83 | +    [CascadingParameter(Name = "MainLayoutRef")]  | 
 | 84 | +    public MainLayout? MainLayoutRef { get; set; }  | 
 | 85 | +
  | 
 | 86 | +    private void ShowNotification()  | 
 | 87 | +    {  | 
 | 88 | +        MainLayoutRef?.NotificationRef?.Show(new NotificationModel()  | 
 | 89 | +        {  | 
 | 90 | +            Text = $"Notification at {DateTime.Now.ToString("HH:mm:ss.fff")}"  | 
 | 91 | +        });  | 
 | 92 | +    }  | 
 | 93 | +
  | 
 | 94 | +    private void HideNotifications()  | 
 | 95 | +    {  | 
 | 96 | +        MainLayoutRef?.NotificationRef?.HideAll();  | 
 | 97 | +    }  | 
 | 98 | +}  | 
 | 99 | +````  | 
 | 100 | + | 
 | 101 | +### Use the Notification as a Service  | 
 | 102 | + | 
 | 103 | +1. Implement a service that holds a Notification component instance as a property and executes component methods.  | 
 | 104 | +1. Register the service in `Program.cs`.  | 
 | 105 | +1. [Define a Telerik Notification component]({%slug notification-overview%}#creating-blazor-notification) in `MainLayout.razor`.  | 
 | 106 | +1. Inject the service in `MainLayout.razor` and [set the Notification `@ref` attribute]({%slug notification-overview%}#notifications-reference-and-methods) to a property of the service.  | 
 | 107 | +1. Inject and use the service in other Razor components.  | 
 | 108 | + | 
 | 109 | +>caption Reuse a Notification in a service  | 
 | 110 | +
  | 
 | 111 | +<div class="skip-repl"></div>  | 
 | 112 | + | 
 | 113 | +````NotificationService.cs  | 
 | 114 | +using Telerik.Blazor.Components;  | 
 | 115 | + | 
 | 116 | +namespace YourAppName.Services  | 
 | 117 | +{  | 
 | 118 | +    public class NotificationService  | 
 | 119 | +    {  | 
 | 120 | +        public TelerikNotification? NotificationRef { get; set; }  | 
 | 121 | + | 
 | 122 | +        public void Show(string text, string? themeColor = null)  | 
 | 123 | +        {  | 
 | 124 | +            NotificationRef?.Show(new NotificationModel()  | 
 | 125 | +            {  | 
 | 126 | +                Text = text,  | 
 | 127 | +                ThemeColor = themeColor  | 
 | 128 | +            });  | 
 | 129 | +        }  | 
 | 130 | + | 
 | 131 | +        public void Show(NotificationModel notificationModel)  | 
 | 132 | +        {  | 
 | 133 | +            NotificationRef?.Show(notificationModel);  | 
 | 134 | +        }  | 
 | 135 | + | 
 | 136 | +        public void HideAll()  | 
 | 137 | +        {  | 
 | 138 | +            NotificationRef?.HideAll();  | 
 | 139 | +        }  | 
 | 140 | +    }  | 
 | 141 | +}  | 
 | 142 | +````  | 
 | 143 | +````Program.cs  | 
 | 144 | +builder.Services.AddSingleton<NotificationService>();  | 
 | 145 | +````  | 
 | 146 | +````_Imports.razor  | 
 | 147 | +@using YourAppName.Services  | 
 | 148 | +````  | 
 | 149 | +````MainLayout.razor  | 
 | 150 | +@inherits LayoutComponentBase  | 
 | 151 | +
  | 
 | 152 | +@inject NotificationService NotificationService  | 
 | 153 | +
  | 
 | 154 | +<TelerikRootComponent>  | 
 | 155 | +
  | 
 | 156 | +    <TelerikNotification @ref="@NotificationService.NotificationRef" />  | 
 | 157 | +
  | 
 | 158 | +    <CascadingValue Value="@this" Name="MainLayoutRef" IsFixed="true">  | 
 | 159 | +        @Body  | 
 | 160 | +    </CascadingValue>  | 
 | 161 | +
  | 
 | 162 | +</TelerikRootComponent>  | 
 | 163 | +````  | 
 | 164 | +````Home.razor  | 
 | 165 | +@page "/"  | 
 | 166 | +
  | 
 | 167 | +@inject NotificationService NotificationService  | 
 | 168 | +
  | 
 | 169 | +<PageTitle>Home</PageTitle>  | 
 | 170 | +
  | 
 | 171 | +<TelerikButton OnClick="@ShowTextNotification">Show Simple Notification</TelerikButton>  | 
 | 172 | +
  | 
 | 173 | +<TelerikButton OnClick="@ShowIconNotification">Show Rich Notification</TelerikButton>  | 
 | 174 | +
  | 
 | 175 | +<TelerikButton OnClick="@HideNotifications">Hide All Notifications</TelerikButton>  | 
 | 176 | +
  | 
 | 177 | +@code {  | 
 | 178 | +    private void ShowTextNotification()  | 
 | 179 | +    {  | 
 | 180 | +        NotificationService.Show($"Notification at {DateTime.Now.ToString("HH:mm:ss.fff")}");  | 
 | 181 | +    }  | 
 | 182 | +
  | 
 | 183 | +    private void ShowIconNotification()  | 
 | 184 | +    {  | 
 | 185 | +        NotificationService.Show(new NotificationModel()  | 
 | 186 | +        {  | 
 | 187 | +            Icon = SvgIcon.Check,  | 
 | 188 | +            Text = $"Notification at {DateTime.Now.ToString("HH:mm:ss.fff")}",  | 
 | 189 | +            ThemeColor = ThemeConstants.Notification.ThemeColor.Success  | 
 | 190 | +        });  | 
 | 191 | +    }  | 
 | 192 | +
  | 
 | 193 | +    private void HideNotifications()  | 
 | 194 | +    {  | 
 | 195 | +        NotificationService.HideAll();  | 
 | 196 | +    }  | 
 | 197 | +}  | 
 | 198 | +````  | 
 | 199 | + | 
 | 200 | +## See Also  | 
 | 201 | + | 
 | 202 | +* [Notification Overview]({%slug notification-overview%})  | 
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