SyncfusionExamples · SreemonPremkumarM · Aug 26, 2025
diff --git a/README.md b/README.md
@@ -1,2 +1,149 @@
-# How to load data on demand using events in wpf treegrid?
-This example illustrates how to load data on demand using events in wpf treegrid
+# How to load data on demand using events in WPF TreeGrid
+
+This example illustrates how to load data on demand using events in [WPF TreeGrid](https://www.syncfusion.com/wpf-controls/treegrid) (SfTreeGrid).
+
+`SfTreeGrid` supports to load the data in on-demand through [SfTreeGrid.RequestTreeItems](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeGrid.SfTreeGrid.html#Syncfusion_UI_Xaml_TreeGrid_SfTreeGrid_RequestTreeItems) event. `RequestTreeItems` event is triggered at the time of loading and when user expand any node at runtime. SfTreeGrid gets the root and leaf nodes through this event handler.
+
+`TreeGridRequestTreeItemsEventArgs.ParentItem` denotes the data object looking for its child nodes. If it is null, it denotes SfTreeGrid requesting root nodes.
+
+In the below example SfTreeGrid is populated through `SfTreeGrid.RequestTreeItems` instead of setting [SfTreeGrid.ItemsSource](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeGrid.SfTreeGrid.html#Syncfusion_UI_Xaml_TreeGrid_SfTreeGrid_ItemsSource).
+
+``` csharp
+ViewModel viewModel = new ViewModel();
+treeGrid.RequestTreeItems += TreeGrid_RequestTreeItems;
+
+private void TreeGrid_RequestTreeItems(object sender, TreeGridRequestTreeItemsEventArgs args)
+{
+
+    if (args.ParentItem == null)
+    {
+        args.ChildItems = viewModel.Employees.Where(x => x.ReportsTo == -1);
+    }
+
+    else
+    {
+        EmployeeInfo employee = args.ParentItem as EmployeeInfo;
+
+        if (employee != null)
+        {
+            args.ChildItems = viewModel.GetEmployees().Where(x => x.ReportsTo == employee.ID);
+        }
+    }
+}
+```
+
+``` csharp
+public class EmployeeInfo
+{
+    int _id;
+    string _firstName;
+    string _lastName;
+    private string _title;
+    double? _salary;
+    int _reportsTo;
+
+    public string FirstName
+    {
+        get { return _firstName; }
+        set { _firstName = value; }
+    }
+
+    public string LastName
+    {
+        get { return _lastName; }
+        set { _lastName = value; }
+    }
+
+    public int ID
+    {
+        get { return _id; }
+        set { _id = value; }
+    }
+
+    public string Title
+    {
+        get { return _title; }
+        set { _title = value; }
+    }
+
+    public double? Salary
+    {
+        get { return _salary; }
+        set { _salary = value; }
+    }
+
+    public int ReportsTo
+    {
+        get { return _reportsTo; }
+        set { _reportsTo = value; }
+    }
+}
+```
+
+``` csharp
+public class ViewModel
+{
+    public ViewModel()
+    {
+        this.Employees = this.GetEmployees();
+    }
+    private ObservableCollection<EmployeeInfo> _employees;
+
+    public ObservableCollection<EmployeeInfo> Employees
+    {
+        get { return _employees; }
+        set { _employees = value; }
+    }
+
+    public ObservableCollection<EmployeeInfo> GetEmployees()
+    {
+        ObservableCollection<EmployeeInfo> employeeDetails = new ObservableCollection<EmployeeInfo>();
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Ferando", LastName = "Joseph", Title = "Management", Salary = 2000000, ReportsTo = -1, ID = 2 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "John", LastName = "Adams", Title = "Accounts", Salary = 2000000, ReportsTo = -1, ID = 3 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Thomas", LastName = "Jefferson", Title = "Sales", Salary = 300000, ReportsTo = -1, ID = 4 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Andrew", LastName = "Madison", Title = "Marketing", Salary = 4000000, ReportsTo = -1, ID = 5 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Ulysses", LastName = "Pierce", Title = "HumanResource", Salary = 1500000, ReportsTo = -1, ID = 6 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Jimmy", LastName = "Harrison", Title = "Purchasing", Salary = 200000, ReportsTo = -1, ID = 7 });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Ronald", LastName = "Fillmore", Title = "Production", Salary = 2800000, ReportsTo = -1, ID = 8 });
+        //Management
+
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Andrew", LastName = "Fuller", ID = 9, Salary = 1200000, ReportsTo = 2, Title = "Vice President" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Janet", LastName = "Leverling", ID = 10, Salary = 1000000, ReportsTo = 2, Title = "GM" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Steven", LastName = "Buchanan", ID = 11, Salary = 900000, ReportsTo = 2, Title = "Manager" });
+
+        //Accounts
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Nancy", LastName = "Davolio", ID = 12, Salary = 850000, ReportsTo = 3, Title = "Accounts Manager" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Margaret", LastName = "Peacock", ID = 13, Salary = 700000, ReportsTo = 3, Title = "Accountant" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Michael", LastName = "Suyama", ID = 14, Salary = 700000, ReportsTo = 3, Title = "Accountant" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Robert", LastName = "King", ID = 15, Salary = 650000, ReportsTo = 3, Title = "Accountant" });
+
+        //Sales
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Laura", LastName = "Callahan", ID = 16, Salary = 900000, ReportsTo = 4, Title = "Sales Manager" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Anne", LastName = "Dodsworth", ID = 17, Salary = 800000, ReportsTo = 4, Title = "Sales Representative" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Albert", LastName = "Hellstern", ID = 18, Salary = 750000, ReportsTo = 4, Title = "Sales Representative" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Tim", LastName = "Smith", ID = 19, Salary = 700000, ReportsTo = 4, Title = "Sales Representative" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Justin", LastName = "Brid", ID = 20, Salary = 700000, ReportsTo = 4, Title = "Sales Representative" });
+
+        //Back Office
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Caroline", LastName = "Patterson", ID = 21, Salary = 800000, ReportsTo = 5, Title = "Receptionist" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Xavier", LastName = "Martin", ID = 22, Salary = 700000, ReportsTo = 5, Title = "Mail Clerk" });
+
+        //HR
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Laurent", LastName = "Pereira", ID = 23, Salary = 900000, ReportsTo = 6, Title = "HR Manager" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Syed", LastName = "Abbas", ID = 24, Salary = 650000, ReportsTo = 6, Title = "HR Assistant" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Amy", LastName = "Alberts", ID = 25, Salary = 650000, ReportsTo = 6, Title = "HR Assistant" });
+
+        //Purchasing
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Pamela", LastName = "Ansman-Wolfe", ID = 26, Salary = 600000, ReportsTo = 7, Title = "Purchase Manager" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Michael", LastName = "Blythe", ID = 27, Salary = 550000, ReportsTo = 7, Title = "Store Keeper" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "David", LastName = "Campbell", ID = 28, Salary = 450000, ReportsTo = 7, Title = "Store Keeper" });
+
+        //Production
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Jillian", LastName = "Carson", ID = 29, Salary = 600000, ReportsTo = 8, Title = "Production Manager" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Shu", LastName = "Ito", ID = 30, Salary = 550000, ReportsTo = 8, Title = "Production Engineer" });
+        employeeDetails.Add(new EmployeeInfo() { FirstName = "Stephen", LastName = "Jiang", ID = 31, Salary = 450000, ReportsTo = 8, Title = "Production Engineer" });
+
+        return employeeDetails;
+    }
+}
+```