wpf: working with data

7/31/2019 WPF: Working with Data

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WPF: Working With Data

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Objectives

• Set how to retrieve data from a SQL Server

database

• Create common data bound forms

• See how to display information from main and

related tables






Agenda

• Data Binding

• Using Views






Data Binding

• Process of getting information from one object

to another and automatically displaying it in

one or more elements in user interface






Without Data Binding

1. In window’s Loaded event handler, query

database and retrieve list of customers

2. In code or in XAML, set ItemsSource property

of list box to DataTable or other object that

contains customers

3. In list box’s SelectionChanged event handler,

query database and retrieve information for

selected customer






Without Data Binding

4. In list box’s SelectionChanged event handler,

set Text property of each text box to value of

appropriate column of customer data

5. In Save button’s Click event handler, read

value of each text box and update appropriate

column of customer data

6. In Save button’s Click event handler, save

changes back to database






With Data Binding

1. In window’s Loaded event handler, query databaseand retrieve list of customers

2. In code or in XAML, set ItemsSource property of list box to DataTable or other object that contains

customers3. In list box’s SelectionChanged event handler, query

database and retrieve information for selectedcustomer

4. In Save button’s Click event handler, save changesback to database






Data Source Options

• Same as in Windows Forms applications

• Many data sources

• Custom business objects

• ADO.NET DataSets• LINQ to SQL

• Entity Framework

• Services

• Web services

• Windows Communication Foundation (WCF) services

• WCF Data Services






Binding to an Object

• Display clients in a list box

• Create collection of clients in code

• Populate the collection

• Bind to object in XAML

• <ListBox

• Name="listBox1"

• DisplayMemberPath="Name"ItemsSource=

• "{Binding ElementName=bindingToObject,Path=Clients}" />






Binding to an Object

• Select a client and display details in data-bound textboxes in a grid

• Bind grid by setting data context to selected list box item

•

Text boxes in grid inherit data binding• <Grid Grid.Row="1" DataContext=

• "{Binding ElementName=listBox1,

• Path=SelectedItem}" >

• <TextBox Text="{Binding Path=Name}"

• Grid.Row="0" Grid.Column="1"

• Margin="5,5,10,5" MaxHeight="25" />






Binding to a DataTable

• Display customers in a list box and details forselected customer in text boxes in grid

• Use TableAdapter or intermediary data layer to retrievecustomers and store in DataTable

• Set ItemsSource property of list box to Customers table

• Grid data context is set to list box selected item

• Text boxes automatically update when a customer is selected

•

List box SelectionChanged event handler runs query toretrieve orders for selected customer






Binding to a LINQ Query

• Display customers in a list box and details forselected customer in text boxes in grid

• Run LINQ to SQL query to retrieve customers

• Set ItemsSource property of results of query• Grid data context is set to list box selected item

• Text boxes automatically update when a customer isselected

• List box SelectionChanged event handler runs LINQ to SQL query to retrieve orders for selectedcustomer






Binding to One Row of Data

• Display information on a product when user

enters product id and clicks Find button

• Use TableAdapter or LINQ to SQL query to retrieve

information on a product

• Set data context of grid to row in DataTable or

result of LINQ query






Demos

• Binding to an Object

• Binding to a DataTable

•

Binding to a LINQ Query• Binding to One Row of Data






Agenda

• Data Binding

• Using Views






Using Views

• When you bind to a collection, WPF creates acollection view

• View manages currency (position of current item)

• Use view to navigate, sort, filter, group

• In code, use instance of CollectionView class

• To get reference to CollectionView, call

GetDefaultView method of CollectionViewSource (XAML representation of view)






CollectionView Class

• Navigation

• Methods: MoveCurrentToFirst, MoveCurrentToPrevious,MoveCurrentToNext, MoveCurrentToLast

• Properties: CurrentItem, CurrentPosition

• Sorting• SortDescriptions property contains collection of

SortDescription structures

• SortDescription specifies column to sort on and order

• SortDescriptions.Add adds a sorting order• SortDescriptions.Clear clears sorting






CollectionView Class

• Filtering

• Cast view to BindingListCollection

• Set CustomFilter property of BindingListCollection

to filter expression

• Set CustomFilter to empty string to clear filter






CollectionViewSource

• XAML representation of view

• Can define views in XAML rather than in code

• <Window.Resources>

• <local:NorthwindDataSet

• x:Key="northwindDataSet" />

• <CollectionViewSource

• x:Key="customersViewSource"

•

Source="{Binding Path=Customers,• Source={StaticResource

• northwindDataSet}}" />

• </Window.Resources>






Demos

• Using a CollectionView

• Using a CollectionViewSource






Drag and Drop Data Binding

• Drag and drop data binding supported in

Windows Forms since Visual Studio 2005

• Now supported in WPF

• Visual Studio creates CollectionViewSources in

XAML when you drag data onto a window

• One-to-many relationships automatically

handled






Demo

• Drag and Drop Data Binding






Learn More!

• This is an excerpt from a larger course. Visitwww.learnnowonline.com for the full details!

•

Learn more about WPF on SlideShare: Intro to Windows Presentation Foundation

(WPF)

WPF: Advanced Controls

WPF: Binding



http://www.slideshare.net/LearnNowOnline/intro-to-wpf

http://www.slideshare.net/LearnNowOnline/wpf-binding




http://www.slideshare.net/LearnNowOnline/intro-to-wpf



wpf: working with data

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