WPF DataGrid - Virtualised - select all - wpf

Question

With a WPF virtualised DataGrid I need to employ a 'select all' method. Iterating though the grid itself won't work as it will only select the records that at visible in the UI - but of course if they are selected using the mouse they are retained. I'm guessing that something must change in the DataTable, but what? If so can it be manipulated so that all the records are selected in the DataGrid?
Thanks
======================== ADDED===========================
Eran - thanks for your reply but having a job wiring this up
Create DataGrid
Dim DGV As New CustomControl.DGVx
With DGV
.Name = "Invoice_AdHoc_DGV"
.AutoGenerateColumns = False
.SelectionMode = SelectionMode.Multiple
End With
RegisterControl(Invoice_AdHoc_Grid, DGV)
RightGrid.Children.Add(DGV)
Bind to DataTable
DGV.ItemsSource = AdHocDT.DefaultView
Created the class from your answer
Public Class ObjectSelectAll
Implements System.ComponentModel.INotifyPropertyChanged
Public Property Name() As String
Private vIsSelected As Boolean
Public Property IsSelected() As Boolean
Get
Return vIsSelected
End Get
Set(value As Boolean)
vIsSelected = value
RaiseEvent PropertyChanged(Me, New System.ComponentModel.PropertyChangedEventArgs("IsSelected"))
End Set
End Property
Public Event PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class

Answer 1

cs :
private List<MyObject> _items;
public List<MyObject> Items
{
get
{
if(_items == null)
_items = new List<MyObject> { new MyObject { Name = "obj1" }, new MyObject { Name = "obj2" }, new MyObject { Name = "obj3" }, new MyObject { Name = "obj4" } };
return _items;
}
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
foreach (var item in Items)
{
item.IsSelected = true;
}
}
}
public class MyObject : INotifyPropertyChanged
{
public string Name { get; set; }
private bool _isSelected;
public bool IsSelected
{
get { return _isSelected; }
set
{
_isSelected = value;
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("IsSelected"));
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
xaml :
<Button Click="Button_Click_1" Content="Select All"/>
<DataGrid Grid.Row="1" AutoGenerateColumns="False" ItemsSource="{Binding Items}">
<DataGrid.RowStyle>
<Style TargetType="DataGridRow">
<Setter Property="IsSelected" Value="{Binding IsSelected}"/>
</Style>
</DataGrid.RowStyle>
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Name}"/>
</DataGrid.Columns>
</DataGrid>

Answer 2

Finally managed to resolve this issue
Added another column to the DataTable
With AdHocDT.Columns
.Add("Selected", GetType(Boolean))
End With
When 'Select All' is clicked set this to True for all rows and in the Grid the value is updated to true as well, then add this to ensure that the Grid shows it as selected when the virtual data is scrolled into view
Private Sub Invoice_AdHoc_DGV_ItemsChanged(sender As Object, e As EventArgs)
Try
Dim DGV As CustomControl.DGVx = Invoice_AdHoc_Grid.FindName("Invoice_AdHoc_DGV")
Dim i As Integer = 0
For Each Row As DataRowView In DGV.Items
Dim vRow As DevComponents.WPF.Controls.AdvGridRow = CType(DGV.ItemContainerManager.ContainerFromItem(DGV.Items(i), False), DevComponents.WPF.Controls.AdvGridRow)
If Not vRow Is Nothing Then
If Row("Selected") = True Then
vRow.IsSelected = True
End If
End If
i += 1
Next
Catch ex As Exception
EmailError(ex)
End Try
End Sub
and handle the event
AddHandler DGV.ItemContainerManager.VisibleContainersChanged, AddressOf Invoice_AdHoc_DGV_ItemsChanged
Now the Grid shows all the rows as selected :-)