Indexer Support

In R2 2016, Telerik introduced Indexer Support for RadPropertyGrid's PropertyDefinition bindings. It covers the following scenarios:

• Binding to an Item of a Collection Through Indexer

• Binding of NestedProperties

• Binding to a collection property with a string key

• Binding to an Item which Implements an Indexer

• Using Unbound Mode

For the purposes of this article, we will assume the following class hierarchy is present:

Example 1: The class hierarchy

• C#
• VB.NET

public class League 
{ 
    public string Name { get; set; } 
    public ObservableCollection<Club> Clubs { get; set; } 
    public Dictionary<string, Club> ClubsDictionary { get; set; } 
} 
public class Club 
{ 
    public string Name { get; set; } 
    public DateTime Established { get; set; } 
    public int StadiumCapacity { get; set; } 
    public ObservableCollection<Player> Players { get; set; } 
    public Player this[int index] 
    { 
        get { return this.Players.First(x => x.Number == index); } 
    } 
} 
public class Player 
{ 
    public string Name { get; set; } 
    public int Number { get; set; } 
    public string Position { get; set; } 
} 

Public Class League 
    Public Property Name() As String 
    Public Property Clubs() As ObservableCollection(Of Club) 
    Public Property ClubsDictionary() As Dictionary(Of String, Club) 
End Class 
Public Class Club 
    Public Property Name() As String 
    Public Property Established() As Date 
    Public Property StadiumCapacity() As Integer 
    Public Property Players() As ObservableCollection(Of Player) 
    Default Public ReadOnly Property Item(ByVal index As Integer) As Player 
        Get 
            Return Me.Players.First(Function(x) x.Number = index) 
        End Get 
    End Property 
End Class 
Public Class Player 
    Public Property Name() As String 
    Public Property Number() As Integer 
    Public Property Position() As String 
End Class 

Binding to an Item of a Collection Through Indexer

A common scenario when using RadPropertyGrid is when we have a collection member of our business object. Example 2 shows how to bind to an item at a specified index in the collection:

Example 2: Binding to a collection

• XAML

<telerik:RadPropertyGrid Item="{Binding League}"  AutoGeneratePropertyDefinitions="False"> 
    <telerik:RadPropertyGrid.PropertyDefinitions> 
        <telerik:PropertyDefinition Binding="{Binding Clubs[0]}" DisplayName="Name" /> 
    </telerik:RadPropertyGrid.PropertyDefinitions> 
</telerik:RadPropertyGrid> 

Binding of NestedProperties

You can also use indexing in NestedProperties, as shown in Example 3:

Example 3: Binding of NestedProperties

• XAML

<telerik:RadPropertyGrid Item="{Binding League}" AutoGeneratePropertyDefinitions="False" NestedPropertiesVisibility="Visible"> 
    <telerik:RadPropertyGrid.PropertyDefinitions> 
        <telerik:PropertyDefinition Binding="{Binding Clubs[0]}" DisplayName="Club"> 
            <telerik:PropertyDefinition.NestedProperties> 
                <telerik:PropertyDefinition DisplayName="Goalkeeper Name" Binding="{Binding Players[0].Name}"/> 
            </telerik:PropertyDefinition.NestedProperties> 
        </telerik:PropertyDefinition> 
    </telerik:RadPropertyGrid.PropertyDefinitions> 
</telerik:RadPropertyGrid> 

Binding to a Collection Property with a String Key

As our League class has a Dictionary of clubs, we can access any club by its name, as demonstrated in Example 4.

Example 4: Binding to item in Dictionary

• XAML

<telerik:RadPropertyGrid Item="{Binding League}" AutoGeneratePropertyDefinitions="False" NestedPropertiesVisibility="Visible"> 
    <telerik:RadPropertyGrid.PropertyDefinitions> 
        <telerik:PropertyDefinition Binding="{Binding ClubsDictionary[Liverpool]}" DisplayName="Club"> 
            <telerik:PropertyDefinition.NestedProperties> 
                <telerik:PropertyDefinition DisplayName="Goalkeeper Name" Binding="{Binding Players[0].Name}"/> 
            </telerik:PropertyDefinition.NestedProperties> 
        </telerik:PropertyDefinition> 
    </telerik:RadPropertyGrid.PropertyDefinitions> 
</telerik:RadPropertyGrid> 

Binding to an Item which Implements an Indexer

Since our Club class implements an indexer, we can also bind to the Player, whose number is 25, for example:

Example 5: Indexing a class that implements indexer

• XAML

<telerik:RadPropertyGrid Item="{Binding League}" AutoGeneratePropertyDefinitions="False"> 
    <telerik:RadPropertyGrid.PropertyDefinitions> 
        <telerik:PropertyDefinition Binding="{Binding ClubsDictionary[Liverpool][25]}" DisplayName="Player with number 25" /> 
    </telerik:RadPropertyGrid.PropertyDefinitions> 
</telerik:RadPropertyGrid> 

Using Unbound Mode

Indexer support also works when AutoGenerateBindingPaths is set to False.

Example 6: Indexing when AutoGenerateBindingPaths is set to False

• XAML

<telerik:RadPropertyGrid Item="{Binding League}" AutoGenerateBindingPaths="False" AutoGeneratePropertyDefinitions="False" NestedPropertiesVisibility="Visible"> 
    <telerik:RadPropertyGrid.PropertyDefinitions> 
        <telerik:PropertyDefinition Binding="{Binding ClubsDictionary[Liverpool]}" DisplayName="Club"> 
            <telerik:PropertyDefinition.NestedProperties> 
                <telerik:PropertyDefinition DisplayName="Chelsea Goalkeeper Name" Binding="{Binding Clubs[Chelsea].Players[0].Name}"/> 
            </telerik:PropertyDefinition.NestedProperties> 
        </telerik:PropertyDefinition> 
    </telerik:RadPropertyGrid.PropertyDefinitions> 
</telerik:RadPropertyGrid>