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How do you show real-time data updates using ObservableCollection?

Platform: Blazor| Category: Data binding

This ObservableCollection (dynamic data collection) provides notifications when items are added, removed, and moved. The implemented INotifyCollectionChanged provides notifications when dynamic changes of adding, removing, moving, and clearing the collection occur. The implementation of INotifyPropertyChanged notifies when property value has changed in client side. Here, Order class implements the interface of INotifyPropertyChanged and it raises the event when CustomerID property value was changed.

[index.razor]

@page "/"
@using System.Collections.ObjectModel
@using System.ComponentModel


<h2>Observable Collections</h2>
<div class="d-flex flex-row my-2">
    <button id="add" @onclick="AddRecords">Add Data</button>
    <button id="del" @onclick="DelRecords">Delete Data</button>
    <button id="update" @onclick="UpdateRecords">Update Data</button>
</div>
<table class="table">
    <thead>
        <tr>
            <th>Customer ID</th>
            <th>Order ID</th>
            <th>Frieght</th>
            <th>Order Date</th>
            <th>Ship Country</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var data in GridData)
        {
            <tr>
                <td>@data.CustomerID</td>
                <td>@data.OrderID</td>
                <td>@data.Freight</td>
                <td>@data.OrderDate</td>
                <td>@data.ShipCountry</td>
            </tr>
        }
    </tbody>
</table>

@code{

    public ObservableCollection<OrdersDetailsObserveData> GridData { get; set; }

    protected override void OnInitialized()
    {
        GridData = OrdersDetailsObserveData.GetRecords();
    }

    public void AddRecords()
    {
        GridData.Add(new OrdersDetailsObserveData(32341, "ALFKI", 4343, 2.3 * 43, false, new DateTime(1991, 05, 15), "Berlin", "Simons bistro", "Denmark", new DateTime(1996, 7, 16), "Kirchgasse 6"));
    }

    public void DelRecords()
    {
        GridData.Remove(GridData.First());
    }

    public void UpdateRecords()
    {
        var a = GridData.First();
        a.CustomerID = "Update";
    }

    public class OrdersDetailsObserveData : INotifyPropertyChanged
    {
        public OrdersDetailsObserveData()
        {
        }
        public OrdersDetailsObserveData(int OrderID, string CustomerId, int EmployeeId, double Freight, bool Verified, DateTime OrderDate, string ShipCity, string ShipName, string ShipCountry, DateTime ShippedDate, string ShipAddress)
        {
            this.OrderID = OrderID;
            this.CustomerID = CustomerId;
            this.EmployeeID = EmployeeId;
            this.Freight = Freight;
            this.ShipCity = ShipCity;
            this.Verified = Verified;
            this.OrderDate = OrderDate;
            this.ShipName = ShipName;
            this.ShipCountry = ShipCountry;
            this.ShippedDate = ShippedDate;
            this.ShipAddress = ShipAddress;
        }
        public static ObservableCollection<OrdersDetailsObserveData> GetRecords()
        {
            ObservableCollection<OrdersDetailsObserveData> order = new ObservableCollection<OrdersDetailsObserveData>();
            int code = 10000;
            for (int i = 1; i < 2; i++)
            {
                order.Add(new OrdersDetailsObserveData(code + 1, "ALFKI", i + 0, 2.3 * i, false, new DateTime(1991, 05, 15), "Berlin", "Simons bistro", "Denmark", new DateTime(1996, 7, 16), "Kirchgasse 6"));
                order.Add(new OrdersDetailsObserveData(code + 2, "ANATR", i + 2, 3.3 * i, true, new DateTime(1990, 04, 04), "Madrid", "Queen Cozinha", "Brazil", new DateTime(1996, 9, 11), "Avda. Azteca 123"));
                order.Add(new OrdersDetailsObserveData(code + 3, "ANTON", i + 1, 4.3 * i, true, new DateTime(1957, 11, 30), "Cholchester", "Frankenversand", "Germany", new DateTime(1996, 10, 7), "Carrera 52 con Ave. Bol�var #65-98 Llano Largo"));
                order.Add(new OrdersDetailsObserveData(code + 4, "BLONP", i + 3, 5.3 * i, false, new DateTime(1930, 10, 22), "Marseille", "Ernst Handel", "Austria", new DateTime(1996, 12, 30), "Magazinweg 7"));
                order.Add(new OrdersDetailsObserveData(code + 5, "BOLID", i + 4, 6.3 * i, true, new DateTime(1953, 02, 18), "Tsawassen", "Hanari Carnes", "Switzerland", new DateTime(1997, 12, 3), "1029 - 12th Ave. S."));
                code += 5;
            }
            return order;
        }

        public int OrderID { get; set; }
        public string CustomerID
        {
            get { return customerID; }
            set
            {
                customerID = value;
                NotifyPropertyChanged("CustomerID");
            }
        }
        public string customerID { get; set; }
        public int EmployeeID { get; set; }
        public double Freight { get; set; }
        public string ShipCity { get; set; }
        public bool Verified { get; set; }
        public DateTime OrderDate { get; set; }

        public event PropertyChangedEventHandler PropertyChanged;

        public string ShipName { get; set; }

        public string ShipCountry { get; set; }

        public DateTime ShippedDate { get; set; }
        public string ShipAddress { get; set; }

        private void NotifyPropertyChanged(String propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

In the sample, we have add, delete and update buttons where the observable data for the table will be populated, removed or updated through the button click.

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