InstanceInitializer Class

Represents item initializers.

Namespace: DevExpress.Xpf.PropertyGrid

Assembly: DevExpress.Xpf.PropertyGrid.v19.2.dll

Declaration

C#

public class InstanceInitializer :
    IInstanceInitializer

VB.NET

Public Class InstanceInitializer
    Implements IInstanceInitializer

Remarks

This example shows how to use the InstanceInitializerAttribute to create objects of a class that does not contain the default constructor.

Click the New Client button within the Clients property menu to set a Clients class instance as the property’s value.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-set-a-property-to-a-custom-value-via-the-popup-menu-t135069.

Data.vb

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel.DataAnnotations
Imports DevExpress.Mvvm.DataAnnotations

Namespace pgrid_attribute
    Public Class EmployeesViewModel
        Private privateData As EmployeesData
        Public Overridable Property Data() As EmployeesData
            Get
                Return privateData
            End Get
            Protected Set(ByVal value As EmployeesData)
                privateData = value
            End Set
        End Property
        Public Sub New()
            Data = New EmployeesData() With {.FirstName = "Anita", .LastName = "Benson", .Group = "Inventory Management", .HireDate = New Date(2002, 2, 2), .Salary = 65000D, .Phone = "7138638137", .Email = "[e-mail]", .AddressLine1 = "9602 South Main", .AddressLine2 = "Seattle, 77025, USA", .BirthDate = New Date(1985, 3, 18)}
        End Sub
    End Class
    Public Class EmployeesData
        Private Const JobGroup As String = "Job"
        Private Const ContactGroup As String = "Contact"
        Private Const AddressGroup As String = "Address"
        Private Const Personal As String = "Personal"
        Private Const NameGroup As String = "Name"

        <Display(GroupName := NameGroup, Name := "First name")> _
        Public Property FirstName() As String
        <Display(GroupName := NameGroup, Name := "Last name")> _
        Public Property LastName() As String

        <Display(GroupName := JobGroup)> _
        Public Property Group() As String
        <DisplayFormat(NullDisplayText := "Title not set"), Display(GroupName := JobGroup)> _
        Public Property Title() As String
        <Display(GroupName := JobGroup, Name := "Hire date")> _
        Public Property HireDate() As Date
        <Display(GroupName := JobGroup), DataType(DataType.Currency)> _
        Public Property Salary() As Decimal

        <Display(GroupName := JobGroup, Name := "Clients"), InstanceInitializer(GetType(Clients), "New Client")> _
        Public Property Clients() As Object

        <Display(GroupName := ContactGroup), DataType(DataType.PhoneNumber)> _
        Public Property Phone() As String
        <Display(GroupName := ContactGroup), DataType(DataType.EmailAddress)> _
        Public Property Email() As String

        <Display(GroupName := Personal, Name := "Birth date"), DisplayFormat(DataFormatString := "m", ApplyFormatInEditMode := True)> _
        Public Property BirthDate() As Date

        <Display(GroupName := AddressGroup, Name := "Address line 1")> _
        Public Property AddressLine1() As String
        <Display(GroupName := AddressGroup, Name := "Address line 2")> _
        Public Property AddressLine2() As String
    End Class
    Public Class Client
        Public Property FirstName() As String
        Public Property LastName() As String
        Public Property Phone() As String
    End Class
    Public Class Clients
        Inherits List(Of Client)

    End Class
End Namespace

MainWindow.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Markup
Imports DevExpress.Mvvm.Native

Namespace pgrid_attribute
    Partial Public Class MainWindow
        Inherits Window

        Public Sub New()
            InitializeComponent()
        End Sub
    End Class
    Public Class ItemInitializer
        Inherits MarkupExtension
        Implements IInstanceInitializer

        Public Overrides Function ProvideValue(ByVal serviceProvider As IServiceProvider) As Object
            Return Me
        End Function
        Private Function IInstanceInitializer_CreateInstance(ByVal type As TypeInfo) As Object Implements IInstanceInitializer.CreateInstance
            Return Date.Today
        End Function
        Private ReadOnly Property IInstanceInitializer_Types() As IEnumerable(Of TypeInfo) Implements IInstanceInitializer.Types
            Get
                Return New List(Of TypeInfo)() From {New TypeInfo(GetType(Date), "Today")}
            End Get
        End Property
    End Class
End Namespace

MainWindow.xaml

<Window x:Class="pgrid_attribute.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
        xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
        xmlns:dxprg="http://schemas.devexpress.com/winfx/2008/xaml/propertygrid" 
        xmlns:local="clr-namespace:pgrid_attribute"
        dx:ThemeManager.ThemeName="Office2013"
        Title="MainWindow" Height="450" Width="600" 
        DataContext="{dxmvvm:ViewModelSource Type={x:Type local:EmployeesViewModel}}">
    <Grid>
        <dxprg:PropertyGridControl
            x:Name="pGrid"
            ShowCategories="True"
            ExpandCategoriesWhenSelectedObjectChanged="True" SelectedObject="{Binding Data}">
            <dxprg:PropertyDefinition Path="HireDate" InstanceInitializer="{local:ItemInitializer}"/>
        </dxprg:PropertyGridControl>
    </Grid>
</Window>

Application.xaml

<Application x:Class="pgrid_attribute.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>

Application.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Threading.Tasks
Imports System.Windows

Namespace pgrid_attribute
    ''' <summary>
    ''' Interaction logic for App.xaml
    ''' </summary>
    Partial Public Class App
        Inherits Application

    End Class
End Namespace

Data.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using DevExpress.Mvvm.DataAnnotations;

namespace pgrid_attribute {
    public class EmployeesViewModel {
        public virtual EmployeesData Data { get; protected set; }
        public EmployeesViewModel() {
            Data = new EmployeesData() {
                FirstName = "Anita",
                LastName = "Benson",
                Group = "Inventory Management",
                HireDate = new DateTime(2002, 2, 2),
                Salary = 65000m,
                Phone = "7138638137",
                Email = "[e-mail]",
                AddressLine1 = "9602 South Main",
                AddressLine2 = "Seattle, 77025, USA",
                BirthDate = new DateTime(1985, 3, 18)
            };
        }
    }
    public class EmployeesData {
        const string JobGroup = "Job";
        const string ContactGroup = "Contact";
        const string AddressGroup = "Address";
        const string Personal = "Personal";
        const string NameGroup = "Name";

        [Display(GroupName = NameGroup, Name = "First name")]
        public string FirstName { get; set; }
        [Display(GroupName = NameGroup, Name = "Last name")]
        public string LastName { get; set; }

        [Display(GroupName = JobGroup)]
        public string Group { get; set; }
        [DisplayFormat(NullDisplayText = "Title not set"), Display(GroupName = JobGroup)]
        public string Title { get; set; }
        [Display(GroupName = JobGroup, Name = "Hire date")]
        public DateTime HireDate { get; set; }
        [Display(GroupName = JobGroup), DataType(DataType.Currency)]
        public decimal Salary { get; set; }

        [Display(GroupName = JobGroup, Name = "Clients")]
        [InstanceInitializer(typeof(Clients), "New Client")]
        public object Clients { get; set; }

        [Display(GroupName = ContactGroup), DataType(DataType.PhoneNumber)]
        public string Phone { get; set; }
        [Display(GroupName = ContactGroup), DataType(DataType.EmailAddress)]
        public string Email { get; set; }

        [Display(GroupName = Personal, Name = "Birth date")]
        [DisplayFormat(DataFormatString = "m", ApplyFormatInEditMode = true)]
        public DateTime BirthDate { get; set; }

        [Display(GroupName = AddressGroup, Name = "Address line 1")]
        public string AddressLine1 { get; set; }
        [Display(GroupName = AddressGroup, Name = "Address line 2")]
        public string AddressLine2 { get; set; }
    }
    public class Client {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Phone { get; set; }
    }
    public class Clients : List<Client> { }
}

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Markup;
using DevExpress.Mvvm.Native;

namespace pgrid_attribute {
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }
    }
    public class ItemInitializer : MarkupExtension, IInstanceInitializer {
        public override object ProvideValue(IServiceProvider serviceProvider) {
            return this;
        }
        object IInstanceInitializer.CreateInstance(TypeInfo type) {
            return DateTime.Today;
        }
        IEnumerable<TypeInfo> IInstanceInitializer.Types {
            get {
                return new List<TypeInfo>() {
                        new TypeInfo(typeof(DateTime), "Today"),
                    };
            }
        }
    }
}

Inheritance

Object

InstanceInitializer