In-Memory Data

The purpose of this tutorial is to show you how to create in-memory data and use it in the context of your WPF application. The following common tasks will be examined:

• Creating in-memory data.

• Setting it as a data source/data context in WPF application.

Creating In-Memory Data

The following example shows how to setup a basic data model along with a view model.

Creating in-memory data

public class Category 
{ 
    public string CategoryName { get; internal set; } 
    public int CategoryID { get; internal set; } 
    public string Description { get; internal set; } 
} 
 
public class ViewModel 
{ 
    private ObservableCollection<Category> categories; 
 
    public ObservableCollection<Category> Categories 
    { 
        get 
        { 
            if(this.categories == null) 
            { 
                this.categories = this.CreateCategories(); 
            } 
            return this.categories; 
        } 
    } 
 
    private ObservableCollection<Category> CreateCategories() 
    { 
        var categories = new ObservableCollection<Category>(); 
        var c = new Category(); 
        c.CategoryID = 1; 
        c.CategoryName = "Beverages"; 
        c.Description = "Soft drinks, coffees, teas, beers, and ales"; 
        categories.Add(c); 
        c = new Category(); 
        c.CategoryID = 2; 
        c.CategoryName = "Condiments"; 
        c.Description = "Sweet and savory sauces, relishes, spreads, and seasonings"; 
        categories.Add(c); 
        c = new Category(); 
        c.CategoryID = 3; 
        c.CategoryName = "Confections"; 
        c.Description = "Desserts, candies, and sweet breads"; 
        categories.Add(c); 
 
        return categories; 
    } 
} 

Public Class Category 
    Private privateCategoryName As String 
    Public Property CategoryName() As String 
        Get 
            Return privateCategoryName 
        End Get 
        Friend Set(ByVal value As String) 
            privateCategoryName = value 
        End Set 
    End Property 
    Private privateCategoryID As Integer 
    Public Property CategoryID() As Integer 
        Get 
            Return privateCategoryID 
        End Get 
        Friend Set(ByVal value As Integer) 
            privateCategoryID = value 
        End Set 
    End Property 
    Private privateDescription As String 
    Public Property Description() As String 
        Get 
            Return privateDescription 
        End Get 
        Friend Set(ByVal value As String) 
            privateDescription = value 
        End Set 
    End Property 
End Class 
 
Public Class ViewModel 
 
    Private _categories As ObservableCollection(Of Category) 
 
    Public ReadOnly Property Categories() As ObservableCollection(Of Category) 
        Get 
            If Me._categories Is Nothing Then 
                Me._categories = Me.CreateCategories() 
            End If 
 
            Return Me._categories 
        End Get 
    End Property 
 
    Private Function CreateCategories() As ObservableCollection(Of Category) 
 
        Dim _categories = New ObservableCollection(Of Category)() 
        Dim c = New Category() 
        c.CategoryID = 1 
        c.CategoryName = "Beverages" 
        c.Description = "Soft drinks, coffees, teas, beers, and ales" 
        _categories.Add(c) 
        c = New Category() 
        c.CategoryID = 2 
        c.CategoryName = "Condiments" 
        c.Description = "Sweet and savory sauces, relishes, spreads, and seasonings" 
        _categories.Add(c) 
        c = New Category() 
        c.CategoryID = 3 
        c.CategoryName = "Confections" 
        c.Description = "Desserts, candies, and sweet breads" 
        _categories.Add(c) 
 
        Return _categories 
    End Function 
End Class 

Setting In-Memory Data as DataSource In WPF Application

You can set the in-memory data as a data source in xaml or in code.

Setting the data source in xaml

<Grid> 
    <Grid.DataContext> 
        <local:ViewModel /> 
    </Grid.DataContext> 
    <telerik:RadTreeView x:Name="radTreeView"  
                         ItemsSource="{Binding Categories}"  
                         DisplayMemberPath="CategoryName"/> 
</Grid> 

Setting the data source in code

public MainWindow() 
{ 
    InitializeComponent(); 
    this.radTreeView.ItemsSource = new ViewModel().Categories; 
} 

Public Sub New() 
    InitializeComponent() 
    Me.radTreeView.ItemsSource = (New ViewModel()).Categories 
End Sub 

See Also

• Using XML