Very often you need “two-way” binding between some UI component with multiple selection and a data context property for selected items – let’s say RadGridView and the following model:

XAML

<telerik:RadGridView  ItemsSource="{Binding  Data}"  SelectionMode="Extended"  SelectedItem="{Binding  SelectedItem,  Mode=TwoWay}">

…
C#

    public class  MyDataContext  :  INotifyPropertyChanged
     {
         ...  ObservableCollection<MyObject> _SelectedItems;
         public  ObservableCollection<MyObject> SelectedItems
        {
             get
             {
                 if  (_SelectedItems ==  null)
                {
                    _SelectedItems =  new  ObservableCollection<MyObject>();
                }
                 return  _SelectedItems;
            }
        }

         MyObject  _SelectedItem;
         public  MyObject  SelectedItem
        {
             get
             {
                 return  _SelectedItem;
            ...

I’ve made small demo on how to create column chooser for any RadGridView in few very simple steps:

1. Add new ChildWindow:

2. Define following XAML for the child window:

<Grid  x:Name="LayoutRoot"  Margin="2">
    <Grid.RowDefinitions>
        <RowDefinition  Height="Auto" />
        <RowDefinition  />
    </Grid.RowDefinitions>
    <TextBlock  Text="Available columns:" />
    <ListBox  ItemsSource="{Binding  Columns}"  Grid.Row="1">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <CheckBox  Content="{Binding  Header}"  IsChecked="{Binding  IsVisible,  Mode=TwoWay}" />
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid...

Creating custom columns for RadGridView is super easy - all you need to do is to override CreateCellElement and/or CreateCellEditElement methods and return desired controls. To illustrate this I’ve made a column with RadProgressBar for view mode and RadSlider for edit mode:
 

And here is the code:

public class  GridViewPercentageColumn  :  GridViewDataColumn
{
     public override  FrameworkElement  CreateCellElement(GridViewCell  cell,  object  dataItem)
    {
         var  bar = cell.Content  as  RadProgressBar;

         if  (bar ==  null)
        {
            bar =  new  RadProgressBar();
            bar.Height = 20;
            bar.SetBinding(RadProgressBar.ValueProperty,  this.DataMemberBinding);
            cell.Content = bar;
        }

         return  bar;
    }

     public override  FrameworkElement  CreateCellEditElement(...

In my previous post I’ve used almost 2 million records to the check the grid performance in WPF and I’ve decided to do the same for Silverlight 4 using WCF RIA Services. The grid again is bound completely codeless using DomainDataSource and RadDataPager:

  <Grid  x:Name="LayoutRoot">
        <Grid.RowDefinitions>
            <RowDefinition  />
            <RowDefinition  Height="Auto" />
        </Grid.RowDefinitions>
        <riaControls:DomainDataSource  Name="orderDomainDataSource"  QueryName="GetOrdersAndOrderDetails">
            <riaControls:DomainDataSource.DomainContext>
                <my:NorthwindDomainContext  />
            </riaControls:DomainDataSource.DomainContext>
        </riaControls:DomainDataSource>
        <telerik:RadGridView  Name="RadGridView1"  IsReadOnly="True"  ...

Just before our upcoming release of Q1 2010 SP1 (early next week), I’ve decided to check how RadGridView for WPF will handle complex Entity Framework 4.0 query with almost 2 million records:

public  class  MyDataContext
{
    IQueryable _Data;
    public  IQueryable Data
    {
        get
        {
            if  (_Data ==  null)
            {
                var northwindEntities =  new  NorthwindEntities();
                var queryable = from o  in  northwindEntities.Orders
                                from od  in  northwindEntities.Order_Details
                                select  new
                                {
                                    od.OrderID,
                                    od.ProductID,
                                    od.UnitPrice,
                                    od.Quantity,
                                    od.Discount,
                                    o.CustomerID,
                                    o.EmployeeID,
                                    o.OrderDate
                                };
                ...

I’ve made small example on how to place RadGridView inside editable RadComboBox and filter the grid items as you type in the combo:

The easiest way to place any UI element in RadComboBox is to create single RadComboBoxItem and define desired Template:

<telerikInput:RadComboBox  Text="{Binding  Text,  Mode=TwoWay}"
                           IsEditable="True"  Height="25"  Width="200">
    <telerikInput:RadComboBox.Items>
        <telerikInput:RadComboBoxItem>
            <telerikInput:RadComboBoxItem.Template>
                <ControlTemplate>
                    <telerikGrid:RadGridView  x:Name="RadGridView1"  ShowGroupPanel="False"  CanUserFreezeColumns="False" 
                                              RowIndicatorVisibility="Collapsed"  IsReadOnly="True"
                                              IsFilteringAllowed="False"  ItemsSource="{Binding  ...

I’m happy to announce that with our upcoming Q1 2010 Service Pack 1 (middle of April) you will be able to apply conditionally styles and templates for RadGridView easily using DataTemplateSelectors and StyleSelectors for both Silverlight and WPF:

You can test the new functionally with our upcoming latest internal build this Friday and in the meantime here is an example:

XAML

<Grid  x:Name="LayoutRoot">
   <Grid.Resources>
        <local:MyStyleSelector  x:Key="styleSelector" />
        <local:MyDataTemplateSelector  x:Key="templateSelector" />
    </Grid.Resources>
    <telerik:RadGridView  AutoGenerateColumns="False"  ItemsSource="{Binding...

I’m happy to inform you that with our latest internal build you will be able to export the grid totals in all supported formats:



Check the attached demo application & enjoy!

Did you know that you can serialize any DataTable to Silverlight easily from your custom WCF service in very few lines of code?

[OperationContract]
public  IEnumerable<Dictionary<string,  object>> GetData()
{
     var  table = YourDataTable;

     var  columns = table.Columns.Cast<DataColumn>();

     return  table.AsEnumerable().Select(r => columns.Select(c =>
                          new  { Column = c.ColumnName, Value = r[c] })
                     .ToDictionary(i => i.Column, i => i.Value !=  DBNull.Value ? i.Value :  null));
}

I’ve made small update for my lightweight DataTable for Silverlight and now you can create the table directly from IEnumerable<Dictionary<string, object>>:

namespace  Telerik.Data
{
     ...

In Silverlight 4 you can use PrintDocument to print easily any UIElement:
…

   var doc = new PrintDocument();
   doc.DocumentName = YourDocumentName;

   doc.PrintPage += (s, e) =>
   {
        e.PageVisual = YouUIElement;
   };
   doc.Print();
…

and I’ve made an extension method that can be used to print any UIElement on multiple pages:

public static void Print(this UIElement source, string documentName)
{
    var doc = new PrintDocument();
    doc.DocumentName = documentName;

    var offsetY = 0d;
    var totalHeight = 0d;

    var canvas = new Canvas();
    canvas.Children.Add(source); ...