How To Load Data On Demand Using Events In Winui Treegrid?
on-demand
treegrid
winui
winui-controls
winui-preview
winui-treegrid
This examples describes how to load data on demand using events in WinUI TreeGrid (SfTreeGrid).
SfTreeGrid supports to load the data in on-demand through 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.
treeGrid.RequestTreeItems += TreeGrid_RequestTreeItems;
private void TreeGrid_RequestTreeItems(object sender, TreeGridRequestTreeItemsEventArgs e)
{
if (e.ParentItem == null)
{
//get the root list - get all employees who have no boss
e.ChildItems = (this.treeGrid.DataContext as ViewModel).EmployeeDetails.Where(x => x.ReportsTo == -1); //get all employees whose boss's id is -1 (no boss)
}
else //if ParentItem not null, then set args.ChildList to the child items for the given ParentItem.
{ //get the children of the parent object
EmployeeInfo emp = e.ParentItem as EmployeeInfo;
if (emp != null)
{
//get all employees that report to the parent employee
e.ChildItems = (this.treeGrid.DataContext as ViewModel).GetReportees(emp.ID);
}
}
}
public class ViewModel : NotificationObject
{
/// <summary>
/// Initializes a new instance of the <see cref="ViewModel"/> class.
/// </summary>
public ViewModel()
{
EmployeeDetails = new List<EmployeeInfo>();
EmployeeDetails.Add(new EmployeeInfo() { FirstName = "Hwakin", ID = 65, LastName = "Grant", Title = "Business Manager", Salary = 200000, ReportsTo = -1 });
EmployeeDetails.Add(new EmployeeInfo() { FirstName = "Madison", ID = 34, LastName = "Bush", Title = "Vice President", Salary = 200000, ReportsTo = -1 });
EmployeeDetails.Add(new EmployeeInfo() { FirstName = "Richard", ID = 36, LastName = "Monroe", Title = "HR Coordinator", Salary = 200000, ReportsTo = -1 });
EmployeeDetails.Add(new EmployeeInfo() { FirstName = "Jack", ID = 43, LastName = "Madison", Title = "Supervisor", Salary = 25000, ReportsTo = 55 });
}
/// <summary>
/// Gets or sets the employee details.
/// </summary>
/// <value>The employee details.</value>
public List<EmployeeInfo> EmployeeDetails
{
get;
set;
}
/// <summary>
/// Gets the reportees.
/// </summary>
/// <param name="bossID">The boss ID.</param>
/// <returns></returns>
public IEnumerable<EmployeeInfo> GetReportees(int bossID)
{
List<EmployeeInfo> list = new List<EmployeeInfo>();
if (bossID == 65)
{
list.Add(new EmployeeInfo() { FirstName = "John", ID = 5, LastName = "Polk", Title = "Marketing Specialist", Salary = 100000, ReportsTo = 65 });
list.Add(new EmployeeInfo() { FirstName = "Bill", ID = 26, LastName = "Wilson", Title = "Senior Tool Designer", Salary = 100000, ReportsTo = 65 });
list.Add(new EmployeeInfo() { FirstName = "Jimmy", ID = 23, LastName = "Harry", Title = "Stocker", Salary = 50000, ReportsTo = 65 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 68, LastName = "Coolidge", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 65 });
}
if (bossID == 34)
{
list.Add(new EmployeeInfo() { FirstName = "Franklin", ID = 24, LastName = "Madison", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 34 });
list.Add(new EmployeeInfo() { FirstName = "William", ID = 66, LastName = "Nixon", Title = "Production Technician", Salary = 40000, ReportsTo = 34 });
list.Add(new EmployeeInfo() { FirstName = "Grover", ID = 35, LastName = "Taft", Title = "Stocker", Salary = 50000, ReportsTo = 34 });
list.Add(new EmployeeInfo() { FirstName = "Bill", ID = 18, LastName = "Nixon", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 34 });
}
if (bossID == 36)
{
list.Add(new EmployeeInfo() { FirstName = "Madison", ID = 64, LastName = "Franklin", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 36 });
list.Add(new EmployeeInfo() { FirstName = "Wilson", ID = 67, LastName = "Harry", Title = "Production Technician", Salary = 40000, ReportsTo = 36 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 59, LastName = "Taft", Title = "Stocker", Salary = 50000, ReportsTo = 36 });
list.Add(new EmployeeInfo() { FirstName = "Jimmy", ID = 08, LastName = "Grover", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 36 });
}
if (bossID == 5)
{
list.Add(new EmployeeInfo() { FirstName = "Franklin", ID = 47, LastName = "William", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 5 });
list.Add(new EmployeeInfo() { FirstName = "Taft", ID = 52, LastName = "Peter", Title = "Production Technician", Salary = 40000, ReportsTo = 5 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 34, LastName = "Wilson", Title = "Stocker", Salary = 50000, ReportsTo = 5 });
list.Add(new EmployeeInfo() { FirstName = "Grover", ID = 41, LastName = "John", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 5 });
}
if (bossID == 26)
{
list.Add(new EmployeeInfo() { FirstName = "Andrew", ID = 11, LastName = "Wilson", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 26 });
list.Add(new EmployeeInfo() { FirstName = "George", ID = 24, LastName = "Madison", Title = "Production Technician", Salary = 40000, ReportsTo = 26 });
list.Add(new EmployeeInfo() { FirstName = "Peter", ID = 33, LastName = "Taft", Title = "Stocker", Salary = 50000, ReportsTo = 26 });
list.Add(new EmployeeInfo() { FirstName = "Jimmy", ID = 54, LastName = "Harry", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 26 });
}
if (bossID == 23)
{
list.Add(new EmployeeInfo() { FirstName = "Bush", ID = 98, LastName = "Bill", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 23 });
list.Add(new EmployeeInfo() { FirstName = "Hayes", ID = 32, LastName = "William", Title = "Production Technician", Salary = 40000, ReportsTo = 23 });
list.Add(new EmployeeInfo() { FirstName = "Madison", ID = 12, LastName = "Franklin", Title = "Stocker", Salary = 50000, ReportsTo = 23 });
list.Add(new EmployeeInfo() { FirstName = "Arthur", ID = 96, LastName = "Grover", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 23 });
}
if (bossID == 18)
{
list.Add(new EmployeeInfo() { FirstName = "Adams", ID = 71, LastName = "Reagan", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 18 });
list.Add(new EmployeeInfo() { FirstName = "Nixon", ID = 92, LastName = "Tyler", Title = "Production Technician", Salary = 40000, ReportsTo = 18 });
list.Add(new EmployeeInfo() { FirstName = "Coolidge", ID = 43, LastName = "Polk", Title = "Design Engineer", Salary = 50000, ReportsTo = 18 });
list.Add(new EmployeeInfo() { FirstName = "George", ID = 84, LastName = "Harrison", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 18 });
}
if (bossID == 68)
{
list.Add(new EmployeeInfo() { FirstName = "Madison", ID = 125, LastName = "Bill", Title = "Marketing Specialist", Salary = 100000, ReportsTo = 68 });
list.Add(new EmployeeInfo() { FirstName = "Nixon", ID = 226, LastName = "Wilson", Title = "Senior Tool Designer", Salary = 100000, ReportsTo = 68 });
list.Add(new EmployeeInfo() { FirstName = "Taft", ID = 253, LastName = "Franklin", Title = "Stocker", Salary = 50000, ReportsTo = 68 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 618, LastName = "Coolidge", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 68 });
}
if (bossID == 24)
{
list.Add(new EmployeeInfo() { FirstName = "Franklin", ID = 244, LastName = "Madison", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 24 });
list.Add(new EmployeeInfo() { FirstName = "William", ID = 166, LastName = "Nixon", Title = "Production Technician", Salary = 40000, ReportsTo = 24 });
list.Add(new EmployeeInfo() { FirstName = "Grover", ID = 355, LastName = "Taft", Title = "Stocker", Salary = 50000, ReportsTo = 24 });
list.Add(new EmployeeInfo() { FirstName = "Bill", ID = 148, LastName = "Harry", Title = "Production Superviser", Salary = 50000, ReportsTo = 24 });
}
if (bossID == 66)
{
list.Add(new EmployeeInfo() { FirstName = "Stogner", ID = 64, LastName = "Martin", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 66 });
list.Add(new EmployeeInfo() { FirstName = "Wilson", ID = 67, LastName = "Harry", Title = "Production Technician", Salary = 40000, ReportsTo = 66 });
list.Add(new EmployeeInfo() { FirstName = "Harrison", ID = 59, LastName = "Will", Title = "Stocker", Salary = 50000, ReportsTo = 66 });
list.Add(new EmployeeInfo() { FirstName = "Jimmy", ID = 08, LastName = "Grover", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 66 });
}
if (bossID == 35)
{
list.Add(new EmployeeInfo() { FirstName = "Franklin", ID = 417, LastName = "William", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 35 });
list.Add(new EmployeeInfo() { FirstName = "Taft", ID = 522, LastName = "Peter", Title = "Production Technician", Salary = 40000, ReportsTo = 35 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 341, LastName = "Wilson", Title = "Stocker", Salary = 50000, ReportsTo = 35 });
list.Add(new EmployeeInfo() { FirstName = "Grover", ID = 141, LastName = "John", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 35 });
}
if (bossID == 64)
{
list.Add(new EmployeeInfo() { FirstName = "Andrew", ID = 141, LastName = "Wilson", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 64 });
list.Add(new EmployeeInfo() { FirstName = "Will", ID = 244, LastName = "Madison", Title = "Production Technician", Salary = 40000, ReportsTo = 64 });
list.Add(new EmployeeInfo() { FirstName = "Harrison", ID = 343, LastName = "Taft", Title = "Stocker", Salary = 50000, ReportsTo = 64 });
list.Add(new EmployeeInfo() { FirstName = "Jimmy", ID = 544, LastName = "Harry", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 64 });
}
if (bossID == 67)
{
list.Add(new EmployeeInfo() { FirstName = "Bush", ID = 98, LastName = "Bill", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 67 });
list.Add(new EmployeeInfo() { FirstName = "Hayes", ID = 32, LastName = "William", Title = "Production Technician", Salary = 40000, ReportsTo = 67 });
list.Add(new EmployeeInfo() { FirstName = "Madison", ID = 12, LastName = "Franklin", Title = "Stocker", Salary = 50000, ReportsTo = 67 });
list.Add(new EmployeeInfo() { FirstName = "Arthur", ID = 96, LastName = "Grover", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 67 });
}
if (bossID == 59)
{
list.Add(new EmployeeInfo() { FirstName = "Adams", ID = 711, LastName = "Reagan", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 59 });
list.Add(new EmployeeInfo() { FirstName = "Nixon", ID = 192, LastName = "Tyler", Title = "Production Technician", Salary = 40000, ReportsTo = 59 });
list.Add(new EmployeeInfo() { FirstName = "Coolidge", ID = 413, LastName = "Polk", Title = "Design Engineer", Salary = 50000, ReportsTo = 59 });
list.Add(new EmployeeInfo() { FirstName = "George", ID = 841, LastName = "Harrison", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 59 });
}
if (bossID == 8)
{
list.Add(new EmployeeInfo() { FirstName = "William", ID = 71, LastName = "Bush", Title = "Quality Assurance Supervisor", Salary = 40000, ReportsTo = 8 });
list.Add(new EmployeeInfo() { FirstName = "Harry", ID = 92, LastName = "Tyler", Title = "Production Technician", Salary = 40000, ReportsTo = 8 });
list.Add(new EmployeeInfo() { FirstName = "Arthur", ID = 43, LastName = "Polk", Title = "Design Engineer", Salary = 50000, ReportsTo = 8 });
list.Add(new EmployeeInfo() { FirstName = "George", ID = 84, LastName = "Harrison", Title = "Maintainence Superviser", Salary = 50000, ReportsTo = 8 });
}
return list;
}
}
You can let SfTreeGrid to populate the data at runtime by calling SfTreeGrid.RepopulateTree method.
