DxTreeList.SelectedDataItems Property

In multiple selection mode, this property specifies data items that correspond to selected TreeList rows.

Assembly : DevExpress.Blazor.v25.2.dll

Declaration

csharp

[Parameter]
public IReadOnlyList<object> SelectedDataItems { get; set; }

Property Value

Type	Description
IReadOnlyList<Object>

The data item collection.

Remarks

The TreeList supports multiple row selection when the SelectionMode property is set to Multiple (the default value). To access data items that correspond to the selected rows, use the SelectedDataItems property as follows:

Implement two-way binding for this property (@bind-SelectedDataItems) to specify initially selected rows and automatically update the property value when selection changes.
Use one-way binding for this property and handle the SelectedDataItemsChanged event to implement a custom response to selection changes.

If SelectionMode is set to Single, use the SelectedDataItem property instead. If you change the selection mode dynamically, specify the SelectedDataItems property and handle the SelectedDataItemsChanged event. In the event handler, check the selection mode and assign the last selected item or all selected items to the SelectedDataItems property.

For additional information about selection in the TreeList component, refer to the following topic: Selection and Focus in Blazor TreeList.

Select and Deselect Items

Rows can be selected and deselected in the following ways:

A user clicks rows, taps rows, or executes keyboard shortcuts to select or deselect rows. To enable this functionality, set the AllowSelectRowByClick property to true.
A user clicks checkboxes in the selection column. To display this column, declare a DxTreeListSelectionColumn object in the Columns template.
You call the Select* or Deselect* method. Refer to the TreeList’s member table for the list of available methods.

Obtain Item Field Values

Pass a data item to the GetDataItemValue method to get the item’s field value when the TreeList is bound to a collection of anonymous objects. In other cases, you can cast a data item to the corresponding type and use the {DataItem.FieldName} notation to get the item’s field value.

The following example allows users to click rows to select them and displays information about the selected rows:

Razor
EmployeeTask.cs
EmployeeTaskService.cs
Program.cs

razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList Data="TreeListData"
            KeyFieldName="Id"
            ParentKeyFieldName="ParentId"
            AllowSelectRowByClick="true"
            @bind-SelectedDataItems="@SelectedDataItems">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
    </Columns>
</DxTreeList>

<div>
    <b>Selected tasks:</b>
    @{
        if(SelectedDataItems != null)
            foreach (var task in SelectedDataItems.Cast<EmployeeTask>()) {    
                <li>@task.Name</li>
            }
    }
</div>

@code {
    List<EmployeeTask> TreeListData { get; set; }
    IReadOnlyList<object> SelectedDataItems { get; set; }

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
}

csharp

public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Progress { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int progress
        )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Progress = progress;
    }
}

csharp

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), 14),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 17),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 11),
            new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 23),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 100),
            new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 37),
            new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), 17),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), 45),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 17),
            new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 18),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 4),
            new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), 73),
            new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), 9),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 5),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 4),
            new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), 14),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 8),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 12),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 14),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 18),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), 21),
            new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), 10),
            new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 96),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 96),
            new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 100)
        };
    }
}

csharp

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Run Demo: TreeList - Multiple Row Selection

You can use the SelectedDataItems property to delete selected rows when a user clicks a button.

Implements

SelectedDataItems