<TelerikButton OnClick="@AddNotifications">Add success, info, warning, error notification</TelerikButton>

<TelerikButton OnClick="@HideAllNotifications">Hide all notifications</TelerikButton>

@if (isNotificationRendered) 
{ 
    <TelerikNotification @ref="@NotificationReference" Class="MyTelerikNotification"></TelerikNotification>
}

@code {
    //hide all implementation
    bool isNotificationRendered { get; set; } = true;
    async Task HideAllNotifications()
    {
        isNotificationRendered = false;
        await InvokeAsync(StateHasChanged);
        await Task.Delay(20);
        isNotificationRendered = true;
    }
    //end


    public TelerikNotification NotificationReference { get; set; }

    public void AddNotifications()
    {
        // Success
        NotificationReference.Show(new NotificationModel()
        {
            ThemeColor = ThemeColors.Success,
            Text = "Success",
        });

        // Info
        NotificationReference.Show(new NotificationModel()
        {
            ThemeColor = ThemeColors.Info,
            Text = "Info",
        });

        // Warning
        NotificationReference.Show(new NotificationModel()
        {
            ThemeColor = ThemeColors.Warning,
            Text = "Warning",
        });

        // Error
        NotificationReference.Show(new NotificationModel()
        {
            ThemeColor = ThemeColors.Error,
            Text = "Error",
        });
    }
}

<style>
    .MyTelerikNotification .k-notification-container .k-notification-wrap {
        width: 300px;
        height: 50px;
        font-size: 1.5em;
        text-align: center;
        align-items: center;
    }
</style>