Artigo
11/18/2011

Selector.SelectedValue Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets or sets the value of the selected item, obtained by using the SelectedValuePath.

Namespace: System.Windows.Controls.Primitives
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
Public Property SelectedValue As Object

public Object SelectedValue { get; set; }

<selector SelectedValue="valueAsString"/>

XAML Values

valueAsString
A string that is equivalent to the desired value as displayed in UI.

Property Value

Type: System.Object
The value of the selected item, obtained by using the SelectedValuePath, or nulla null reference (Nothing in Visual Basic) if no item is selected. The default value is nulla null reference (Nothing in Visual Basic).

Remarks

Dependency property identifier field: SelectedValueProperty

Getting the value of SelectedValue returns the value of the SelectedItem, using SelectedValuePath. For example, if you have a control derived from Selector that is bound to a collection of objects of type Employee, and Employee has two properties named EmployeeName and EmployeeNumber. You can set SelectedValuePath to "EmployeeNumber" to have SelectedValue return the value of EmployeeNumber.

Examples

The following example shows how to use the SelectedValuePath and SelectedValue properties with a ComboBox control. The DisplayMemberPath is set to the name of the displayed document, and the SelectedValuePath is set to the ID property. In this example, the ID for the selected item is simply displayed on the screen, but in a real application, you could use it to retrieve the selected object.

Run this sample

    Public MyDocs As System.Collections.ObjectModel.ObservableCollection(Of Document) =
        New System.Collections.ObjectModel.ObservableCollection(Of Document)

    Public Sub New()
        MyBase.New()
        InitializeComponent()
        ' Add items to the collection.
        MyDocs.Add(New Document("How to: Use SelectedValuePath"))
        MyDocs.Add(New Document("DataGrid Overview"))
        MyDocs.Add(New Document("Silverlight Designer Overview"))
        comboBox1.DataContext = MyDocs
        textBlock2.DataContext = comboBox1
    End Sub
End Class

' Simple business object.
Public Class Document
    Private nameValue As String
    Private guidValue As Guid

    Public Sub New()
        MyBase.New()

    End Sub

    Public Sub New(ByVal docName As String)
        MyBase.New()
        guidValue = Guid.NewGuid()
        Name = docName
    End Sub

    Public Property Name As String
        Get

            Return nameValue

        End Get
        Set(ByVal value As String)
            nameValue = value
        End Set

    End Property

    Public Property ID As Guid
        Get
            Return guidValue
        End Get
        Set(ByVal value As Guid)
            guidValue = value
        End Set

    End Property
End Class

public partial class MainPage : UserControl
{

    public System.Collections.ObjectModel.ObservableCollection<Document> MyDocs =
        new System.Collections.ObjectModel.ObservableCollection<Document>();
    public MainPage()
    {
        InitializeComponent();

        // Add items to the collection.
        MyDocs.Add(new Document("How to: Use SelectedValuePath"));
        MyDocs.Add(new Document("DataGrid Overview"));
        MyDocs.Add(new Document("Silverlight Designer Overview"));
        comboBox1.DataContext = MyDocs;
        textBlock2.DataContext = comboBox1;
    }
}

// Simple business object.
public class Document
{
    public Document() { }
    public Document(string docName)
    {
        ID = Guid.NewGuid();
        Name = docName;
    }
    public string Name { get; set; }
    public Guid ID { get; set; }

}

    <UserControl x:Class="SelectedValuePath.MainPage"
    xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="https://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="https://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">
    <StackPanel x:Name="LayoutRoot" Background="White" Height="312" Width="400">
        <ComboBox Height="23" ItemsSource="{Binding}" DisplayMemberPath="Name" 
                  SelectedValuePath="ID" 
                  HorizontalAlignment="Left" Margin="5" Name="comboBox1" 
                   Width="238" />
        <TextBlock Height="18" HorizontalAlignment="Left" Margin="5" 
                   Name="textBlock1" Text="Selected Value (GUID):"  Width="238" />
        <TextBlock Height="32" HorizontalAlignment="Left"  Name="textBlock2" 
                   Width="238" Text="{Binding SelectedValue}"/>
    </StackPanel>
</UserControl>

Version Information

Silverlight

Supported in: 5, 4

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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