Modifies the source data before passing it to the target for display in the UI.
Syntax
Function Convert( value As Object, targetType As Type, parameter As Object, language As String ) As Object
Parameters
- value
-
Type: System.Object [.NET] | Platform::Object [C++]
The source data being passed to the target.
- targetType
-
Type: System.Type [.NET] | TypeName [C++]
The type of the target property, specified by a helper structure that wraps the type name.
- parameter
-
Type: System.Object [.NET] | Platform::Object [C++]
An optional parameter to be used in the converter logic.
- language
-
Type: System.String [.NET] | Platform::String [C++]
The language of the conversion.
Return value
Type: System.Object [.NET] | Platform::Object [C++]
The value to be passed to the target dependency property.
Examples
The following example shows how to implement the Convert method using the parameter and language parameters.
Imports System.Collections.ObjectModel Imports System.Windows.Data Imports System.Globalization Partial Public Class Page Inherits UserControl Public MyMusic As New ObservableCollection(Of Recording)() Public Sub New() InitializeComponent() ' Add items to the collection. MyMusic.Add(New Recording("Sheryl Crow", "Detours", New DateTime(2008, 2, 5))) MyMusic.Add(New Recording("Brandi Carlisle", "The Story", New DateTime(2007, 4, 3))) MyMusic.Add(New Recording("Patty Griffin", "Children Running Through", New DateTime(2007, 2, 6))) ' Set the data context for the combo box. MusicCombo.DataContext = MyMusic End Sub End Class ' Simple business object. Public Class Recording Public Sub New() End Sub Public Sub New(ByVal artistName As String, ByVal cdName As String, _ ByVal release As DateTime) Artist = artistName Name = cdName ReleaseDate = release End Sub Private artistValue As String Private nameValue As String Private releaseDateValue As DateTime Public Property Artist() As String Get Return artistValue End Get Set(ByVal value As String) artistValue = value End Set End Property Public Property Name() As String Get Return nameValue End Get Set(ByVal value As String) nameValue = value End Set End Property Public Property ReleaseDate() As DateTime Get Return releaseDateValue End Get Set(ByVal value As DateTime) releaseDateValue = value End Set End Property End Class Public Class DateFormatter Implements IValueConverter ' This converts the DateTime object to the string to display. Public Function Convert(ByVal value As Object, ByVal targetType As Type, _ ByVal parameter As Object, ByVal language As System.String) As Object _ Implements IValueConverter.Convert ' Retrieve the format string and use it to format the value. Dim formatString As String = TryCast(parameter, String) If Not String.IsNullOrEmpty(formatString) Then Return String.Format(New CultureInfo(language), formatString, value) End If ' If the format string is null or empty, simply call ToString() ' on the value. Return value.ToString() End Function ' No need to implement converting back on a one-way binding. Public Function ConvertBack(ByVal value As Object, ByVal targetType As Type, _ ByVal parameter As Object, _ ByVal language As System.String) As Object _ Implements IValueConverter.ConvertBack Throw New NotImplementedException() End Function End Class
Requirements
|
Minimum supported client | Windows 8 |
|---|---|
|
Minimum supported server | Windows Server 2012 |
|
Namespace |
|
|
Metadata |
|
See also
Build date: 12/4/2012