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Asynchronous data loading with Entity Data Source?

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DataPager

This is a migrated thread and some comments may be shown as answers.

Samuel asked on 15 Jul 2015, 04:46 PM

I have a GridView where the ItemsSource is bound to the PagedSource property of a DataPager. The DataPager ItemsSource is bound to an EntityDataSource. The problem is that this is blocking my UI thread. The GridView has a "DataLoadMode" property which can be set to Asynchronous... but the pager doesn't. How would I go about loading the data to the pager asynchronously? I tried doing this in another thread but I keep getting a cross-thread exception even though I use the dispatcher to set the property to which the pager is bound.

<telerik:RadGridView x:Name="RadGridView1"

Grid.Row="0"

Margin="5,5,5,0"

HorizontalAlignment="Stretch"

VerticalAlignment="Stretch"

AlternateRowBackground="LightBlue"

AlternationCount="2"

AutoGenerateColumns="False"

CanUserDeleteRows="False"

CanUserFreezeColumns="False"

CanUserInsertRows="False"

DataLoadMode="Asynchronous"

GroupRenderMode="Nested"

IsReadOnly="True"

ItemsSource="{Binding ElementName=DataPager1,

Path=PagedSource}"

RowIndicatorVisibility="Collapsed"

ShowGroupPanel="False"

telerik:StyleManager.Theme="Summer">

<telerik:RadGridView.Columns>

<telerik:GridViewDataColumn Width="60"

DataMemberBinding="{Binding StoreNumber}"

Header="Store"

ShowDistinctFilters="True"

ShowFieldFilters="False"

TextAlignment="Center" />

<telerik:GridViewDataColumn Width="80"

DataFormatString="dd-MMM-yyyy"

DataMemberBinding="{Binding ASNDate}"

Header="Ship Date"

ShowDistinctFilters="False"

SortingState="Descending"

TextAlignment="Center" />

<telerik:GridViewDataColumn Width="Auto"

MinWidth="80"

DataMemberBinding="{Binding PONumber}"

Header="PO"

ShowDistinctFilters="False"

TextAlignment="Center" />

<telerik:GridViewDataColumn Width="80"

DataFormatString="dd-MMM-yyyy"

DataMemberBinding="{Binding PODate}"

Header="PO Date"

ShowDistinctFilters="False"

TextAlignment="Center" />

<telerik:GridViewDataColumn Width="Auto"

MinWidth="80"

DataMemberBinding="{Binding InvoiceNumber}"

Header="Invoice"

ShowDistinctFilters="False"

TextAlignment="Center" />

<telerik:GridViewDataColumn Width="Auto"

DataMemberBinding="{Binding ToteID}"

Header="Tote"

ShowDistinctFilters="True"

TextAlignment="Center">

<telerik:GridViewDataColumn.CellTemplate>

<DataTemplate>

<TextBlock Width="Auto"

Height="Auto"

HorizontalAlignment="Center"

VerticalAlignment="Center">

<Hyperlink Click="OnToteClick" Tag="{Binding}">

<TextBlock Width="Auto"

Height="Auto"

HorizontalAlignment="Center"

VerticalAlignment="Center"

Text="{Binding ToteID}" />

</Hyperlink>

</TextBlock>

</DataTemplate>

</telerik:GridViewDataColumn.CellTemplate>

</telerik:GridViewDataColumn>

<telerik:GridViewDataColumn Width="80"

DataFormatString="dd-MMM-yyyy"

DataMemberBinding="{Binding Closed}"

Header="Completed"

ShowDistinctFilters="False" />

<telerik:GridViewDataColumn Width="Auto"

DataMemberBinding="{Binding ClosedByName}"

Header="Complete By"

ShowDistinctFilters="True"

ShowFieldFilters="False"

TextAlignment="Center" />

</telerik:RadGridView.Columns>

</telerik:RadGridView>

<telerik:RadDataPager x:Name="DataPager1"

Grid.Row="1"

Width="{Binding ActualWidth,

ElementName=RadGridView1}"

Margin="5,0,5,5"

DisplayMode="FirstLastPreviousNextNumeric"

PageSize="{Binding PageSize,

Mode=TwoWay}"

Source="{Binding ShipmentData}"

telerik:StyleManager.Theme="Summer" />

public class ShipmentsViewModel : ViewModelBase

{

private readonly TIMS.Data.TIMSContext ctx =new Data.TIMSContext();

public ShipmentsViewModel()

{

}

#region Properties

private int PageSizeValue = 20;

public int PageSize

{

get { return PageSizeValue; }

set

{

SetPropertyValue((() => PageSize), ref PageSizeValue, value);

}

private QueryableEntityCollectionView<TIMS.Data.Entities.ToteView> ShipmentDataValue;

public QueryableEntityCollectionView<TIMS.Data.Entities.ToteView> ShipmentData

{

get {

return ShipmentDataValue;

}

private set

{

SetPropertyValue((() => ShipmentData), ref ShipmentDataValue, value);

}

#endregion

#region Methods

public override void OnNavigatedTo(Uri view, object data)

{

try

{

IsBusy = true;

System.Threading.ThreadPool.QueueUserWorkItem(delegate

{

var shipments = new QueryableEntityCollectionView<Data.Entities.ToteView>(((IObjectContextAdapter)ctx).ObjectContext, "ToteViews");

if (App.Store != null)

{

shipments.FilterDescriptors.Add(new FilterDescriptor("StoreNumber", FilterOperator.IsEqualTo, App.Store.Value, false));

}

App.Current.Dispatcher.Invoke(new Action(delegate

{

ShipmentDataValue = shipments;

IsBusy = false;

}));

});

}

catch (Exception e)

{

App.Current.Dispatcher.BeginInvoke(new Action(delegate

{

var dlg = new ChildWindows.ErrorDialog("0012: An unknown error occured.");

App.LogError(e);

dlg.ShowDialog();

IsBusy = false;

}));

}

#endregion

#region Commands

#endregion

}

1 Answer, 1 is accepted

answered on 16 Jul 2015, 12:37 PM

Hello,

For the time being, RadEntityFrameworkDataSource does not support async loading. I have made a Feature Request on this public: Asynchronous support.
You can vote for it and also follow the item to get notified once there is a change in its Status.

For the time being, I can suggest you considering RadDataServiceDataSource, which handles all operations asynchronously.

Regards,
Dimitrina
Telerik

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