VirtualSourceBase.KeyProperty Property

Gets or sets a name of key field. The virtual source uses this field to reload specific rows and find the selected row after refresh.

Namespace: DevExpress.Xpf.Data

Assembly: DevExpress.Xpf.Core.v24.1.dll

NuGet Package: DevExpress.Wpf.Core

Declaration

C#

public string KeyProperty { get; set; }

VB.NET

Public Property KeyProperty As String

Property Value

Type	Description
String	A name of key field.

Remarks

Reload Individual Rows

Use the InfiniteAsyncSource.ReloadRows / PagedAsyncSource.ReloadRows method to update individual rows.

C#

private void Button_Click(object sender, RoutedEventArgs e) {
    int[] selectedRowIds = grid.SelectedItems.Cast<IssueData>().Select(x => x.Id).ToArray();
    ((InfiniteAsyncSource)(grid.ItemsSource)).ReloadRows(selectedRowIds);
}  

VB.NET

Private Sub Button_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    Dim selectedRowIds As Integer() = grid.SelectedItems.Cast(Of IssueData)().[Select](Function(x) x.Id).ToArray()
    (CType((grid.ItemsSource), InfiniteAsyncSource)).ReloadRows(selectedRowIds)
End Sub

Specify the KeyProperty property to allow a virtual source to construct a filter with an InOperator.

C#

var source = new InfiniteAsyncSource() {
    ElementType = typeof(IssueData),
    KeyProperty = nameof(IssueData.Id)
};  

VB.NET

Dim source = New InfiniteAsyncSource() With {
    .ElementType = GetType(IssueData),
    .KeyProperty = NameOf(IssueData.Id)
} 

C#

public class IssueData {
    public int Id { get; private set; }
    public string Subject { get; private set; }
    public string User { get; private set; }
    public DateTime Created { get; private set; }
    public int Votes { get; private set; }
    public Priority Priority { get; private set; }
} 

VB.NET

Public Class IssueData
    Public Property Id As Integer
    Public Property Subject As String
    Public Property User As String
    Public Property Created As DateTime
    Public Property Votes As Integer
    Public Property Priority As Priority
End Class 

Retain a Selected Row and Scroll Position After Refresh

The FetchRowsEventArgsBase.Take property returns the number of rows that should be reloaded. Use this property to allow the InfiniteAsyncSource to retain a selected row and scroll position after refresh. The PagedAsyncSource retains a selected row and scroll position by default.

If data in your source are changed frequently, you can retain the same selected row after refresh. Specify the KeyProperty property to make a virtual source find the selected row by a specific field:

C#

var source = new InfiniteAsyncSource() {
    ElementType = typeof(IssueData),
    KeyProperty = nameof(IssueData.Id)
};  

VB.NET

Dim source = New InfiniteAsyncSource() With {
    .ElementType = GetType(IssueData),
    .KeyProperty = NameOf(IssueData.Id)
} 

C#

public class IssueData {
    public int Id { get; private set; }
    public string Subject { get; private set; }
    public string User { get; private set; }
    public DateTime Created { get; private set; }
    public int Votes { get; private set; }
    public Priority Priority { get; private set; }
} 

VB.NET

Public Class IssueData
    Public Property Id As Integer
    Public Property Subject As String
    Public Property User As String
    Public Property Created As DateTime
    Public Property Votes As Integer
    Public Property Priority As Priority
End Class 

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the KeyProperty property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

XAML

wpf-data-grid-implement-crud-operations/CS/ViewModel/EFCore/PagedAsyncSource/MainWindow.xaml#L29

<dxg:GridControl.ItemsSource>
    <dx:PagedAsyncSource ElementType="local_issues:Issue" KeyProperty="Id"
                         PageNavigationMode="ArbitraryWithTotalPageCount" FetchPageCommand="{Binding FetchPageCommand}"

how-to-bind-wpf-grid-to-data/CS/ViewModel/EFCore/InfiniteAsyncSource/MainWindow.xaml#L17

<dxg:GridControl.ItemsSource>
    <dx:InfiniteAsyncSource ElementType="local_issues:Issue" KeyProperty="Id"
                            FetchRowsCommand="{Binding FetchRowsCommand}" GetTotalSummariesCommand="{Binding GetTotalSummariesCommand}" />