Wednesday, October 16, 2013

Searching in Windows Phone ListBox

One of the most common way of searching in ListBox is to type text in TextBox and filter the ListBox items. In this article we will see how we can do this in Windows Phone application.

As you can see in above image, we have a TextBox where user can type, and a ListBox which get filtered based on text entered.


    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    <!--LayoutRoot is the root grid where all page content is placed-->
    <Grid x:Name="LayoutRoot" Background="Transparent">
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        <!--TitlePanel contains the name of the application and page title-->
        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12">
            <TextBlock x:Name="ApplicationTitle" TextAlignment="Center"  Text="SEARCHABLE LISTBOX" Style="{StaticResource PhoneTextNormalStyle}"/>
        <!--ContentPanel - place additional content here-->
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="*"/>
            <TextBox Grid.Row="0" Name="txtSearchText"/>
            <ListBox Grid.Row="1" Background="LightGray" Name="lstData" Margin="12,0"/>

Windows Phone has a class called CollectionView which allows grouping, sorting, filtering and navigation in a data collection. To create a collection view for a collection that implements IEnumerable, we can create a CollectionViewSource object, and add collection to the Source property. To filter the data based on TextBox text, we have to add event handler for Filter event.

Private Sub BindListBox()
       mTechnologiesCollectionSource.Source = mTechnologies
       Dim b As New Binding
       AddHandler mTechnologiesCollectionSource.Filter, AddressOf mTechnologiesCollectionSource_Filter
       b.Source = mTechnologiesCollectionSource
       lstData.SetBinding(ListBox.ItemsSourceProperty, b)
End Sub
Private Sub mTechnologiesCollectionSource_Filter(sender As Object, e As FilterEventArgs)
       Dim str As String = e.Item
       If String.IsNullOrWhiteSpace(txtSearchText.Text) = True OrElse str.ToUpperInvariant.StartsWith(txtSearchText.Text.ToUpperInvariant) = True Then
           e.Accepted = True
           e.Accepted = False
       End If
End Sub

In the above code, we are using "StartsWith" function to filter the Collection, and show the items which starts with text typed in TextBox. We can also use "Contains" function instead of "StartsWith" to show all the items which contains text typed in TextBox.

Private Sub mTechnologiesCollectionSource_Filter(sender As Object, e As FilterEventArgs)
       Dim str As String = e.Item
       If String.IsNullOrWhiteSpace(txtSearchText.Text) = True OrElse str.ToUpperInvariant.Contains(txtSearchText.Text.ToUpperInvariant) = True Then
           e.Accepted = True
           e.Accepted = False
       End If
End Sub

On TextChanged event on TextBox to reapply the filter we have to refresh the view using "CollectionViewSource.View.Refresh" function.

Imports System.Collections.ObjectModel
Imports System.Windows.Data
Partial Public Class MainPage
    Inherits PhoneApplicationPage
    Dim mTechnologies As New ObservableCollection(Of String)
    Dim mTechnologiesCollectionSource As New CollectionViewSource
    ' Constructor
    Public Sub New()
    End Sub
    Private Sub FillListBox()
        mTechnologies.Add("Visual Basic")
        mTechnologies.Add("Visual C#")
        mTechnologies.Add("Visual F#")
        mTechnologies.Add("Window Communication Foundation")
        mTechnologies.Add("Window Presentation Foundation")
        mTechnologies.Add("Window Phone")
    End Sub
    Private Sub MainPage_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
    End Sub
    Private Sub BindListBox()
        mTechnologiesCollectionSource.Source = mTechnologies
        Dim b As New Binding
        AddHandler mTechnologiesCollectionSource.Filter, AddressOf mTechnologiesCollectionSource_Filter
        b.Source = mTechnologiesCollectionSource
        lstData.SetBinding(ListBox.ItemsSourceProperty, b)
    End Sub
    Private Sub mTechnologiesCollectionSource_Filter(sender As Object, e As FilterEventArgs)
        Dim str As String = e.Item
        If String.IsNullOrWhiteSpace(txtSearchText.Text) = True OrElse str.ToUpperInvariant.StartsWith(txtSearchText.Text.ToUpperInvariant) = True Then
            e.Accepted = True
            e.Accepted = False
        End If
    End Sub
    Private Sub txtSearchText_TextChanged(sender As Object, e As TextChangedEventArgs) Handles txtSearchText.TextChanged
    End Sub
End Class

You can also refer following links to know more about CollectionViewSource

Friday, July 26, 2013

Editable Button in WPF

Today I am going to share a code snippet to create an Editable Button in WPF, where we can update the text of a Button at runtime. In this control the user would right-click a button and then click 'Edit' to make to control Editable, and later right-click it to save/cancel the change.

First step to make the Button editable is to change the Style of Button and add a TextBox inside it, which we will make visible when the user clicks on 'Edit'.

01.<Style TargetType="my:EditableButton">
02.    <Setter Property="FocusVisualStyle">
03.        <Setter.Value>
04.            <Style>
05.                <Setter Property="Control.Template">
06.                    <Setter.Value>
07.                        <ControlTemplate>
08.                            <Rectangle Margin="2" SnapsToDevicePixels="True" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
09.                        </ControlTemplate>
10.                    </Setter.Value>
11.                </Setter>
12.            </Style>
13.        </Setter.Value>
14.    </Setter>
15.    <Setter Property="Background" Value="#FFDDDDDD"/>
16.    <Setter Property="BorderBrush" Value="#FF707070"/>
17.    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
18.    <Setter Property="BorderThickness" Value="1"/>
19.    <Setter Property="HorizontalContentAlignment" Value="Center"/>
20.    <Setter Property="VerticalContentAlignment" Value="Center"/>
21.    <Setter Property="Padding" Value="1"/>
22.    <Setter Property="Template">
23.        <Setter.Value>
24.            <ControlTemplate TargetType="{x:Type Button}">
25.                <Border x:Name="border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True">
26.                    <Grid>
27.                        <ContentPresenter x:Name="tbkContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" Focusable="False" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
28.                        <TextBox   Name="txtContent" Height="{TemplateBinding Height}" TextAlignment="Center" Visibility="Collapsed" Text="{TemplateBinding Content}" Padding="0" Background="Transparent" BorderBrush="Transparent" BorderThickness="0" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"  VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" Margin="{TemplateBinding Padding}"/>
29.                    </Grid>
30.                </Border>
31.                <ControlTemplate.Triggers>
32.                    <Trigger Property="IsDefaulted" Value="True">
33.                        <Setter Property="BorderBrush" TargetName="border" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
34.                    </Trigger>
35.                    <Trigger Property="IsMouseOver" Value="True">
36.                        <Setter Property="Background" TargetName="border" Value="#FFBEE6FD"/>
37.                        <Setter Property="BorderBrush" TargetName="border" Value="#FF3C7FB1"/>
38.                    </Trigger>
39.                    <Trigger Property="IsPressed" Value="True">
40.                        <Setter Property="Background" TargetName="border" Value="#FFC4E5F6"/>
41.                        <Setter Property="BorderBrush" TargetName="border" Value="#FF2C628B"/>
42.                    </Trigger>
43.                    <Trigger Property="ToggleButton.IsChecked" Value="True">
44.                        <Setter Property="Background" TargetName="border" Value="#FFBCDDEE"/>
45.                        <Setter Property="BorderBrush" TargetName="border" Value="#FF245A83"/>
46.                    </Trigger>
47.                    <Trigger Property="IsEnabled" Value="False">
48.                        <Setter Property="Background" TargetName="border" Value="#FFF4F4F4"/>
49.                        <Setter Property="BorderBrush" TargetName="border" Value="#FFADB2B5"/>
50.                        <Setter Property="TextElement.Foreground" TargetName="tbkContent" Value="#FF838383"/>
51.                    </Trigger>
52.                </ControlTemplate.Triggers>
53.            </ControlTemplate>
54.        </Setter.Value>
55.    </Setter>

As you can see in the above code, I have added a "txtContent" textbox which is hidden. Also to make editing look like a part of the Button, the Background and BorderBrush properties of textbox are transparent

01.Public Class EditableButton
02.    Inherits Button
03.    Private mButtonContentPresenter As ContentPresenter
04.    Private mButtonTextBox As TextBox
06.    Public Sub New()
07.        Me.DefaultStyleKey = GetType(EditableButton)
08.        AddHandler Me.Loaded, New RoutedEventHandler(AddressOf EditableButton_Loaded)
09.    End Sub
11.    Private Sub EditableButton_Loaded(sender As Object, e As RoutedEventArgs)
13.        Me.OnApplyTemplate()
14.    End Sub
16.    Public Overrides Sub OnApplyTemplate()
17.        MyBase.OnApplyTemplate()
18.        mButtonContentPresenter = DirectCast(Me.GetTemplateChild("tbkContent"), ContentPresenter)
19.        mButtonTextBox = DirectCast(Me.GetTemplateChild("txtContent"), TextBox)
20.        CreateSaveContextMenu()
21.        CreateEditContextMenu()
22.    End Sub
24.    Public Property IsEditMode() As Boolean
25.        Get
26.            Return CBool(GetValue(IsEditModeProperty))
27.        End Get
28.        Private Set(value As Boolean)
29.            SetValue(IsEditModeProperty, value)
30.        End Set
31.    End Property
33.    ' Using a DependencyProperty as the backing store for IsEditMode.  This enables animation, styling, binding, etc...
34.    Public Shared ReadOnly IsEditModeProperty As DependencyProperty = DependencyProperty.Register("IsEditMode", GetType(Boolean), GetType(EditableButton), New PropertyMetadata(False))
36.    Private Sub CreateSaveContextMenu()
37.        Dim menu As New ContextMenu
38.        Dim itm As New MenuItem()
39.        itm.Header = "Save"
40.        AddHandler itm.Click, New RoutedEventHandler(AddressOf itmSave_Click)
41.        menu.Items.Add(itm)
43.        itm = New MenuItem()
44.        itm.Header = "Cancel"
45.        AddHandler itm.Click, New RoutedEventHandler(AddressOf itmCancel_Click)
46.        menu.Items.Add(itm)
48.        ContextMenuService.SetContextMenu(mButtonTextBox, menu)
49.    End Sub
53.    Private Sub CreateEditContextMenu()
54.        Dim menu As New ContextMenu
55.        Dim itm As New MenuItem
56.        itm.Header = "Edit"
57.        AddHandler itm.Click, New RoutedEventHandler(AddressOf itmEdit_Click)
58.        menu.Items.Add(itm)
60.        ContextMenuService.SetContextMenu(mButtonContentPresenter, menu)
61.    End Sub
63.    Private Sub itmEdit_Click(sender As Object, e As RoutedEventArgs)
64.        mButtonContentPresenter.Visibility = Visibility.Collapsed
65.        mButtonTextBox.Visibility = Visibility.Visible
66.        IsEditMode = True
67.    End Sub
69.    Private Sub itmSave_Click(sender As Object, e As RoutedEventArgs)
70.        mButtonContentPresenter.Visibility = Visibility.Visible
71.        mButtonTextBox.Visibility = Visibility.Collapsed
72.        Me.Content = mButtonTextBox.Text
73.        IsEditMode = False
74.    End Sub
76.    Private Sub itmCancel_Click(sender As Object, e As RoutedEventArgs)
77.        mButtonContentPresenter.Visibility = Visibility.Visible
78.        mButtonTextBox.Visibility = Visibility.Collapsed
79.        IsEditMode = False
80.    End Sub
81.End Class

In the above code we have an "IsEditMode" property which the user can use to know whether the control is in Edit Mode or not. Also, we have two different Context Menus, one to Edit the Control, and the another to Save/Cancel the changes. Based on the menuitems that are clicked, we are going to set the visibility of TextBox and ContentPresenter, defined in XAML.

Now we can use the control in our application as below

01.<Window x:Class="MainWindow"
04.    xmlns:my="clr-namespace:WpfApplication1"
05.    Title="MainWindow" Height="350" Width="525">
07.    <Grid>
08.        <my:EditableButton x:Name="MyButton" Width="100" Height="25" Content="Edit Me"/>
09.    </Grid>

Hope the above control helps you in your development.