TreeListSelectionColumnCellDisplayTemplateContext.SelectEnabled Property

Returns whether the select operation is available for a row from a remote data source.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.1.dll

NuGet Package: DevExpress.Blazor

Declaration

C#

public bool SelectEnabled { get; }

Property Value

Type	Description
Boolean	true if the select operation is available; otherwise, false.

Remarks

A selection column contains checkboxes or radio buttons depending on the selection mode. You can define the column’s CellDisplayTemplate to display custom select elements in column cells that correspond to data rows.

The select operation can be temporarily unavailable if you bind the TreeList to the GridDevExtremeDataSource or load data on demand. The SelectEnabled context parameter returns false while the select operation cannot be performed. Once this operation becomes available, this parameter returns true.

In the template, use the SelectEnabled parameter to specify the enabled or disabled state for a custom select element. In the same way, you can use the SelectAllEnabled parameter in the selection column’s HeaderTemplate.

Razor

@inject CitiesService CitiesService

<DxTreeList Data="@Data"
            KeyFieldName="ID" 
            ParentKeyFieldName="ParentID" 
            HasChildrenFieldName="HasChildren"
            SelectionMode="TreeListSelectionMode.Single"
            @bind-SelectedDataItem="@SelectedDataItem">
    <Columns>
        <DxTreeListSelectionColumn>
            <CellDisplayTemplate >
                <DxButton Click="@(() => context.TreeList.SelectRow(context.VisibleIndex))"
                          Text="Select" RenderStyle="ButtonRenderStyle.Link"
                          Enabled="context.SelectEnabled"/>
            </CellDisplayTemplate>
        </DxTreeListSelectionColumn>
        <DxTreeListDataColumn Caption="Location" FieldName="Name" />
        <DxTreeListDataColumn FieldName="CityType" />
        <DxTreeListDataColumn FieldName="Year" DisplayFormat="d"/>
        <DxTreeListDataColumn FieldName="RecordType" />
        <DxTreeListDataColumn FieldName="Population" />
    </Columns>
</DxTreeList> 

@code {
    object Data { get; set; }
    object SelectedDataItem { get; set; }

    protected override async Task OnInitializedAsync() {
        var cities = await CitiesService.GetCitiesAsync();
        Data = new GridDevExtremeDataSource<Location>(cities.AsQueryable());
    }
}

Location.cs

public class Location {
    public string? Name { get; set; }
    public string? City { get; set; }
    public string? Country { get; set; }
    public decimal Population { get; set; }
    public int ID { get; set; }
    public int ParentID { get; set; }
    public string? CityType { get; set; }
    public string? RecordType { get; set; }
    public int? Year { get; set; }
    public bool HasChildren { get; set; }
}

CitiesService.cs

public class CitiesService {
    CitiesContext _context;
    public CitiesService(IDbContextFactory<CitiesContext> contextFactory) {
        _context = contextFactory.CreateDbContext();
    }
    public void SeedData() {
        _context.Database.EnsureCreated();
        if (_context.Locations.Any())
            return;
        var stream = File.OpenRead(@"cities.json");
        var cities = System.Text.Json.JsonSerializer.Deserialize<Location[]>(stream);
        if (cities == null)
            return;
        foreach (var city in cities) {
            city.ID++;
            city.ParentID++;
        }
        _context.Locations.AddRange(cities);
        _context.SaveChanges();
    }

    public async Task<Location[]?> GetCitiesAsync() {
        await _context.Locations.LoadAsync();
        return _context.Locations.Local.ToArray();
    }
}