DxTreeList.SelectRows(IEnumerable<Int32>, Boolean) Method

Selects or deselects rows with the specified visible indexes.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.2.dll

NuGet Package: DevExpress.Blazor

Declaration

public void SelectRows(
    IEnumerable<int> visibleIndexes,
    bool selected = true
)

Parameters

Name	Type	Description
visibleIndexes	IEnumerable<Int32>	Specifies a collection of visible indexes.

Optional Parameters

Name	Type	Default	Description
selected	Boolean	True	true to select rows; false to deselect rows.

Remarks

The following methods allow you to manage TreeList selection:

• SelectRow (DeselectRow)
• SelectRows (DeselectRows)
• SelectDataItem (DeselectDataItem)
• SelectDataItems (DeselectDataItems)
• SelectAllOnPage (DeselectAllOnPage)
• SelectAllAsync (DeselectAllAsync)
• ClearSelection

When the SelectionMode property is set to Multiple, the SelectRows method allows you to add multiple rows to the current selection. Call this method and pass a collection of visible indexes as the parameter.

If you call the SelectRows method in Single mode, it clears selection and selects only one row with the last specified index.

Note

Rows that are filtered out and child rows of collapsed items do not have visible indexes. You cannot change the selection state of such rows with DeselectRows and SelectRows methods.

When the TreeList is bound to the GridDevExtremeDataSource or loads data on demand, call the WaitForRemoteSourceRowLoadAsync(Int32) method before you execute the SelectRows method to ensure that the specified data rows are loaded.

You can deselect rows with specified visible indexes in the following ways:

• Call the DeselectRows method.
• Call the SelectRows method and pass false as the second parameter.

To access data items that correspond to selected rows, implement two-way binding for the SelectedDataItems property or handle the SelectedDataItemsChanged event.

Tip

When you call the SelectRow or DeselectRow method, the component sends a callback and redraws the TreeList. If you select or deselect multiple rows, for instance, in a cycle, it can reduce overall performance. Call the SelectRows or DeselectRows method instead to avoid unnecessary callbacks and redraws.

The following example selects and deselects rows whose indexes are between 3 and 5:

Razor

@inject EmployeeTaskService EmployeeTaskService

<style>
    .my-button {
        width: 200px;
    }
</style>

<DxTreeList @ref="MyTreeList"
            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>

<DxButton Click="() => MyTreeList.SelectRows(RowIndexes)" CssClass="my-button" Text="Select Rows 4-6"/>
<DxButton Click="() => MyTreeList.DeselectRows(RowIndexes)" CssClass="my-button" Text="Deselect Rows 4-6"/>

@code {
    List<EmployeeTask> TreeListData { get; set; }
    IReadOnlyList<object> SelectedDataItems { get; set; }
    ITreeList MyTreeList { get; set; }
    int[] RowIndexes { get; set; } = new int[] { 3, 4, 5 };

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

EmployeeTask.cs

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 EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate
    )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
    }
}

EmployeeTaskService.cs

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

Program.cs

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

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

Implements

SelectRows(IEnumerable<Int32>, Boolean)

SelectRows(IEnumerable<Int32>, Boolean)