ForeignKeyConfiguration Property (Column)

Gets or sets a ForeignKeyConfiguration through which the visual representation of a foreign key description can be configured.

Syntax

Visual Basic
C#

'Declaration
 
Public Property ForeignKeyConfiguration As ForeignKeyConfiguration

'Usage
 
Dim instance As Column
Dim value As ForeignKeyConfiguration
 
instance.ForeignKeyConfiguration = value
 
value = instance.ForeignKeyConfiguration

public ForeignKeyConfiguration ForeignKeyConfiguration {get; set;}

Property Value

A reference to a ForeignKeyConfiguration through which the visual representation of a foreign key description can be configured.

Remarks

By default, if a CellContentTemplate is specified, the same template will be applied to the foreign key configuration (see EmployeeID column in Example 1). For simpler configurations, or when a cell-content template is not required, a configuration's ValuePath and DisplayMemberPath can be used to indicate the path to the value on the source object that corresponds to the "key" and the path to its its visual representation, respectively (see ShipVia and CustomerID columns in Example).

Example

All examples in this topic assume that the grid is bound to the Orders table of the Northwind database or a collection of Person objects, unless stated otherwise.

The following example demonstrates how to define foreign key configurations for foreign key descriptions that were automatically created from the constraints extracted from the underlying DataTable.

XAML

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
 <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                       Source="{Binding Source={x:Static Application.Current}, Path=Orders}"
                                       AutoCreateForeignKeyDescriptions="True"/>
 </Grid.Resources>      
 
 <xcdg:DataGridControl x:Name="OrdersGrid"
                       ItemsSource="{Binding Source={StaticResource cvs_orders}}"
                       AutoCreateForeignKeyConfigurations="True">
    <xcdg:DataGridControl.Columns>
       <xcdg:Column FieldName="EmployeeID"
                    Title="Employee">
          <xcdg:Column.CellContentTemplate>
             <DataTemplate>
                <StackPanel Orientation="Horizontal">
                   <TextBlock Text="{Binding FirstName}" />
                   <TextBlock Text=" " />
                   <TextBlock Text="{Binding LastName}" />
                </StackPanel>
             </DataTemplate>
          </xcdg:Column.CellContentTemplate>
       </xcdg:Column>
       <xcdg:Column FieldName="CustomerID"
                    Title="Customer">
          <xcdg:Column.ForeignKeyConfiguration>
             <xcdg:ForeignKeyConfiguration DisplayMemberPath="CompanyName"
                                           ValuePath="CustomerID" />
          </xcdg:Column.ForeignKeyConfiguration>
       </xcdg:Column>
       
       <xcdg:Column FieldName="ShipVia"
                    Title="Shipping Company">
          <xcdg:Column.ForeignKeyConfiguration>
             <xcdg:ForeignKeyConfiguration DisplayMemberPath="CompanyName"
                                           ValuePath="ShipperID" />
          </xcdg:Column.ForeignKeyConfiguration>
       </xcdg:Column>
    </xcdg:DataGridControl.Columns>
 </xcdg:DataGridControl>
</Grid>

The following example demonstrates how to bind the grid directly to a BindingList objects and provide a custom key/value mapping through a ForeignKeyConverter, which will return the appropriate employee first and last names for the provided employee ID.

XAML

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
  <Grid.Resources>
     <local:OccupationToStringConverter x:Key="occupationToStringConverter" />
     <local:PersonForeignKeyConverter x:Key="personForeignKeyConverter" />

     <ObjectDataProvider x:Key="occupationValues"
                         MethodName="GetValues"
                         ObjectType="{x:Type sys:Enum}">
        <ObjectDataProvider.MethodParameters>
           <x:Type TypeName="local:Occupation" />
        </ObjectDataProvider.MethodParameters>
     </ObjectDataProvider>

  </Grid.Resources>     
 
  <xcdg:DataGridControl x:Name="PersonsGrid"
                        ItemsSource="{Binding Source={x:Static Application.Current}, Path=Persons}">

    <xcdg:DataGridControl.Columns>
       <xcdg:Column FieldName="Occupation">
          <xcdg:Column.CellContentTemplate>
             <DataTemplate>
                <TextBlock Text="{Binding Converter={StaticResource occupationToStringConverter}}" />
             </DataTemplate>
          </xcdg:Column.CellContentTemplate>
          <xcdg:Column.ForeignKeyConfiguration>
             <xcdg:ForeignKeyConfiguration ItemsSource="{Binding Source={StaticResource occupationValues}}" />
          </xcdg:Column.ForeignKeyConfiguration>
       </xcdg:Column>
       <xcdg:Column FieldName="ReportsTo">
          <xcdg:Column.CellContentTemplate>
             <DataTemplate>
                <StackPanel Orientation="Horizontal">
                   <TextBlock Text="{Binding FirstName}" />
                   <TextBlock Text=" " />
                   <TextBlock Text="{Binding LastName}" />
                </StackPanel>
             </DataTemplate>
          </xcdg:Column.CellContentTemplate>
          <xcdg:Column.ForeignKeyConfiguration>
             <xcdg:ForeignKeyConfiguration ItemsSource="{Binding Source={x:Static Application.Current}, Path=Persons}"
                                           ForeignKeyConverter="{StaticResource personForeignKeyConverter}"
                                           ValuePath="PersonID"/>
          </xcdg:Column.ForeignKeyConfiguration>
       </xcdg:Column>
    </xcdg:DataGridControl.Columns>
  </xcdg:DataGridControl>
</Grid>

The following code provides the implementation of the PersonForeignKeyConverter class.

Visual Basic

Public Class PersonForeignKeyConverter
             Inherits ForeignKeyConverter

  Public Overrides Function GetKeyFromValue( value As Object, configuration As ForeignKeyConfiguration ) As Object
    Dim bindingList As PersonBindingList = TryCast( configuration.ItemsSource, PersonBindingList )
    If Not bindingList Is Nothing Then
      Dim person As Person = TryCast( value, Person )
      If Not person Is Nothing Then
        Return person.PersonID
      End If
    End If
    Return -1
  End Function
  Public Overrides Function GetValueFromKey( key As Object, configuration As ForeignKeyConfiguration ) As Object
   Dim bindingList As PersonBindingList = TryCast( configuration.ItemsSource, PersonBindingList )
    If Not bindingList Is Nothing Then
      Try
        Dim personID As Integer = CInt( key )
        Dim person As Person
        For Each person In bindingList
          If person.PersonID = personID Then
            Return person
          End If
        Next person
      Catch e As Exception
        ' key can be nothing
      End Try
    Return Nothing
  End Function
End Class

The following code provides the implementation of the PersonForeignKeyConverter class.

public class PersonForeignKeyConverter : ForeignKeyConverter
{
 public override object GetKeyFromValue( object value, ForeignKeyConfiguration configuration )
 {
   PersonBindingList bindingList = configuration.ItemsSource as PersonBindingList;
   if( bindingList != null )
   {
     Person person = value as Person;
     if( person != null )
     {
       return person.PersonID;
     }
   }
   return -1;
 }
 public override object GetValueFromKey( object key, ForeignKeyConfiguration configuration )
 {
   PersonBindingList bindingList = configuration.ItemsSource as PersonBindingList;
   if( bindingList != null )
   {
     try
     {
       int personID = ( int )key;
       foreach( Person person in bindingList )
       {
         if( person.PersonID == personID )
         {
           return person;
         }
       }
     }
     catch( Exception )
     {
       // key can be null
     }
   }
   return null;
 }
}

Requirements

Target Platforms: Windows 11, Windows 10, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Column Class
Column Members

DataGrid Fundamentals

Foreign Key Detection