WPF Discussion Boards

beginner : binding ListBox

26-Sep-12 18:25

Sorry about the heading, but I really couldnt resist. The question is realted to arcitecture of the implementation of ViewModels in WPF, and its based on the application a wrote an article about here[^], and the code that Im wondering about changing to, hopefully, something better is this:

I have a MainViewModel class where I initiate a Property of ObservableCollections, that contains elements of this class:

Public Class RadioButtonProperies

        Private _Text As String
        Public Property Text() As String
            Get
                Return _Text
            End Get
            Set(ByVal value As String)
                _Text = value
            End Set
        End Property

        Private _Index As Integer
        Public Property Index() As Integer
            Get
                Return _Index
            End Get
            Set(ByVal value As Integer)
                _Index = value
            End Set
        End Property

        Private _IsChecked As Boolean = False
        Public Property IsChecked() As Boolean
            Get
                Return _IsChecked
            End Get
            Set(ByVal value As Boolean)
                _IsChecked = value
                If value Then
                    SelectionIndexChanged(Index)
                End If
            End Set
        End Property

        Public Event SelectionIndexUpdated(ByVal index As Integer)

        Private Sub SelectionIndexChanged(ByVal index As Integer)
            RaiseEvent SelectionIndexUpdated(index)
        End Sub

    End Class

As you can see, I Raise an event when the IsChecked property is set to true, and this event is also raised and passed on from the MAinViewModel class, so I can react if you changed the RadioButton selection on the MainWindow:

'Store a pointer to a ViewModel cthat contains all the RadioButtons
Private _Intersections As MainViewModel

Public Sub New()

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.

    'Get all the radiobuttons, and add a handler to Selection changed
    _Intersections = DirectCast(rbtn.DataContext, MainViewModel)
    AddHandler _Intersections.SelectionIndexUpdated, AddressOf rbtnSelectionChanged
End Sub


Public Sub rbtnSelectionChanged(ByVal Value As Integer)
    'Sets the enum of selection on the child control
    DrawingControl.DrawingCanvas.CanvasEvent = Value
End Sub

My question is this: theres got to be a more effective way of doing this, as my implementation is really cumbersome, and the more I look at it the more ridiculose it seems, and the more i dislike it.

What are the guidelines for implementing functionallity like this? Are there any other ways whitch is easyer or better? Any thoughts?

Regards

Kenneth

dominioYP26-Sep-12 4:05

Re: beginner : binding ListBox

26-Sep-12 4:05

class c#:

using System.Collections.ObjectModel;

namespace WpfApplication3
{
    bindingListBoxTOstring.xaml
    public partial class bindingListBoxTOstring : Window
    {
        
        ObservableCollection<ListBoxData> _ListBoxCollection =
            new ObservableCollection<ListBoxData>();
        public bindingListBoxTOstring()
        {
            InitializeComponent();
            _ListBoxCollection.Add(new ListBoxData 
                          { Profilo = "netgear" });
            _ListBoxCollection.Add(new ListBoxData 
                          { Profilo = "alice13" });
        }


        public ObservableCollection<ListBoxData> ListBoxCollection
        { get { return _ListBoxCollection; } }

        public class ListBoxData
        {
            public string Profilo { get; set; }
        }
    }

}

in XAML which property should I use to make binding??
XAML code:

XML

<Window x:Class="WpfApplication3.bindingListBoxTOstring"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="bindingListBoxTOstring" Height="300" Width="300">
    <Grid>
        <ListBox Height="100"  HorizontalAlignment="Left"
           Margin="108,67,0,0" Name="listBox1" 
           VerticalAlignment="Top" Width="120" />
            
    </Grid>
</Window>

WPF, binding, ListBox

Pete O'Hanlon26-Sep-12 4:26

Re: beginner : binding ListBox

26-Sep-12 4:26

In your ListBox, you need to set the ItemsSource to your ListBoxCollection. To do this, you would add ItemsSource="{Binding ListBoxCollection}" in the ListBox. You also need to set the DataSource - as you are just learning, I would suggest keeping it simple and put DataContext = this; immediately after the call to InitializeComponent();.

Finally, you need to actually display something in your ListBox - if you run the application as it stands, you won't see the underlying data because WPF has no way to tell that it should be displaying Profilo. What you want to do is add an ItemTemplate to your ListBox (I'll leave that to you to look up). So, your XAML will look like this:

XML

<ListBox ItemsSource="{Binding ListBoxCollection}" ... put in your other settings here>
  <ListBox.ItemTemplate>
    <DataTemplate>
      <StackPanel>
        <TextBlock Text="{Binding Profilo}" />
      </StackPanel>
    </DataTemplate>
  </ListBox.ItemTemplate>
</ListBox>

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

dominioYP26-Sep-12 5:41

Re: beginner : binding ListBox

26-Sep-12 5:41

ok!! it works! Smile | :)

dominioYP28-Sep-12 5:38

beginner : listView, add scrollBar

28-Sep-12 5:38

before taking this way, I would add items to the listbox like this:

void InserisciItemInListBox(string s, ListBox lb)
        {
            ListBoxItem lbi = new ListBoxItem();
            lbi.Content = s;
            lb.Items.Add(lbi);
        }

after that, I check which item was selected

private void ListBoxSelectedPrintText(object sender, SelectionChangedEventArgs e)
{
    ListBoxItem item = ((ListBox)sender).SelectedItem as ListBoxItem;
    String itemText = (item != null) ? item.Content.ToString() : String.Empty;
    tb.Text = "   You selected " + itemText; ;
}

i've updated XAML

XML

<ListBox ItemsSource="{Binding ProfiliCollection}"
                         Width="100" SelectionChanged="ListBoxSelectedPrintText"
                         ...

now I can not extract the text of the item selected, how do I fix it?

dominioYP26-Sep-12 3:50

Trying to set focus on DataGrid with DataGridTemplateColumn

26-Sep-12 3:50

hello
I added a scrollbar, but it does not work
help me please

XML

<ListView ItemsSource="{Binding GameCollection}" ScrollViewer.VerticalScrollBarVisibility="Visible">

here is the immgine of my problem
linkToSnap

abollmeyer23-Sep-12 3:44

abollmeyer

23-Sep-12 3:44

Hello, I have a DataGrid that I am using where the user clicks a button to add information to the DataGrid. I would like to set focus to the first cell when the user clicks the button. My previous code worked great in a plain ol' DataGridTextColumn, but no longer works.

Here is my XAML:

HTML

<DataGrid.Columns>
                    <DataGridTemplateColumn x:Name="partName" 
                                             Header="Part Name" 
                                             CanUserResize="True" 
                                             Width="225" 
                                             MinWidth="225">
                        <DataGridTemplateColumn.CellTemplate>
                            <DataTemplate>
                                <TextBlock VerticalAlignment="Center" Focusable="True" FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Self}}">
                                    <Hyperlink NavigateUri="http://www.bing.com"
                                               RequestNavigate="Hyperlink_RequestNavigate"
                                               TextDecorations="None">
                                        <TextBlock Text="{Binding Path=description}" x:Name="hyperLinkTextBlock"
                                                   FontSize="20" 
                                                   FontWeight="Black" 
                                                   TextWrapping="WrapWithOverflow"
                                                   TextDecorations="Underline" 
                                                   Focusable="True"
                                                   FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Self}}"/>
                                    </Hyperlink>                                        
                                </TextBlock>
                            </DataTemplate>
                        </DataGridTemplateColumn.CellTemplate>
                        <DataGridTemplateColumn.CellEditingTemplate>
                            <DataTemplate>
                                <TextBox FontSize="20" 
                                         FontWeight="Black" 
                                         HorizontalAlignment="Stretch"          
                                         VerticalContentAlignment="Center"/>
                            </DataTemplate>
                        </DataGridTemplateColumn.CellEditingTemplate>
                    </DataGridTemplateColumn>

And here is my C# code:

partsDataGrid.Focus();
                partsDataGrid.UpdateLayout();
                DataGridCellInfo cellInfo = new DataGridCellInfo (partsDataGrid.Items[0], partsDataGrid.Columns[0]);
                partsDataGrid.CurrentCell = cellInfo;

                partsDataGrid.BeginEdit();

What am I doing wrong? Thanks in advance!

Re: Trying to set focus on DataGrid with DataGridTemplateColumn

abollmeyer24-Sep-12 14:13

abollmeyer

24-Sep-12 14:13

Just for anyone else, I discovered my problem. Even though I had set everything inside my DataGridTemplateColumn to focusable, I hadn't set focusable to true inside my CellStyle.

On ContextMenu MouseLeave

Kenneth Haugland21-Sep-12 3:46

Re: On ContextMenu MouseLeave

21-Sep-12 3:46

I have a custom user control that inherits FrameWorkElement and draws some custom shapes on a canvas. I added this code to get the context menus for the item:

Sub New()
        
        ......
        
        Dim contextmenu As New ContextMenu()
        Dim mi As New MenuItem()
        Dim mia As New MenuItem()
        mi.Header = ("Item 1")
        contextmenu.Items.Add(mi)
        mia.Header = ("Item 2")
        contextmenu.Items.Add(mia)
        AddHandler contextmenu.MouseLeave, AddressOf CloseContextmenu
        Me.ContextMenu = (contextmenu)
End Sub

    Private Sub CloseContextmenu(ByVal sender As Object, ByVal e As Input.MouseEventArgs)
        Me.ContextMenu.IsOpen = False
    End Sub

Which does close the contextmenu, but not when you leave the menu, only when you click outside the contextmenu. My question is has anybody managed to close the contextmenu on mouse leave?

Kenneth Haugland21-Sep-12 13:42

WPF DataGrid Not SHowing Any Data

21-Sep-12 13:42

Ok, I nearly sovled this myself, though its not the ideal solution:

If Mouse.RightButton = MouseButtonState.Pressed Then
                If TypeOf (selectedElement) Is CustomElement Then
                    Dim ga As CustomLine = DirectCast(selectedElement, CustomElement)
                    Dim contextmenu As New ContextMenu()

                    Dim bord As New StackPanel
                    Dim mi As New MenuItem()
                    Dim mia As New MenuItem()
                    mi.Header = ("Item 1")
                    mia.Header = ("Item 2")

                    bord.Children.Add(mi)
                    bord.Children.Add(mia)

                    AddHandler bord.MouseLeave, AddressOf menuitem1_leave

                    contextmenu.Items.Add(bord)
                    contextmenu.IsOpen = True
                    ga.ContextMenu = (contextmenu)
                End If
            End If

with the mouse leave sub:

Private Sub menuitem1_leave(ByVal sender As Object, ByVal e As Input.MouseEventArgs)
     Dim dep As DependencyObject = DirectCast(e.OriginalSource, DependencyObject)

     'Stepping through the visual tree
     While (dep IsNot Nothing) AndAlso Not (TypeOf dep Is ContextMenu)
         dep = VisualTreeHelper.GetParent(dep)
     End While

     If dep Is Nothing Then
         Exit Sub
     End If

     DirectCast(dep, ContextMenu).IsOpen = False
 End Sub

Problem is that the items are messed up inside the ContextMenu, so it looks wierd. So the next question is does anybod have any ideas on how to do this properly?

Kevin Marois20-Sep-12 11:30

Kevin Marois

20-Sep-12 11:30

When I set AutoGenerateColumns = false, then I see no data. I see the data when AutoGenerateColumns = True. Here's my grid:

<DataGrid Grid.Row="1"
            Grid.Column="0"
            Grid.ColumnSpan="2"
            Margin="5"
            ItemsSource="{Binding AccountItems}"
            SelectedItem="{Binding SelectedAccountItem}"
            AutoGenerateColumns="True">
    <DataGrid.Columns>
        <DataGridTemplateColumn Header="Date" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding DisplayDate}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTemplateColumn Header="Memo 1" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Memo1}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

        <DataGridTemplateColumn Header="Memo 2" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Memo2}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTemplateColumn Header="Debit" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Debit}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTemplateColumn Header="Credit" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Credit}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTemplateColumn Header="Balance" 
                                Width="SizeToCells" 
                                IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Balance}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

What am I doing wrong here?

Thanks

If it's not broken, fix it until it is

Kenneth Haugland20-Sep-12 11:47

20-Sep-12 11:47

Not exactly sure but the http://msdn.microsoft.com/en-us/library/system.windows.controls.datagrid.autogeneratecolumns.aspx[^] seems to give an answer:

XML

<!-- The DataGrid.DataContext is a DataTable that contains a list of customers.  The DataTable columns are  
     Title, FirstName, MiddleName, LastName, Suffix, CompanyName, EmailAddress, and Phone.-->
<DataGrid Name="DG1" ItemsSource="{Binding}" AutoGenerateColumns="True" AutoGeneratingColumn="DG1_AutoGeneratingColumn" />

and in the code behind:

//Access and update columns during autogeneration
private void DG1_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
    string headername = e.Column.Header.ToString();

    //Cancel the column you don't want to generate
    if (headername == "MiddleName")
    {
        e.Cancel = true;
    }

    //update column details when generating
    if (headername == "FirstName")
    {
        e.Column.Header = "First Name";
    }
    else if (headername == "LastName")
    {
        e.Column.Header = "Last Name";
    }
    else if (headername == "EmailAddress")
    {
        e.Column.Header = "Email";

    }

}

You could use the code and step through the code with the debugger, at least then you could see whats going on.

modified 20-Sep-12 18:10pm.

Pete O'Hanlon20-Sep-12 11:59

20-Sep-12 11:59

Kenneth Haugland wrote:
Windows Forms Designer

He's talking about WPF, not Windows Forms, and he's put what looks like well formed templates in there.

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Kenneth Haugland20-Sep-12 12:10

20-Sep-12 12:10

Dang it... Sigh | :sigh:

Pete O'Hanlon20-Sep-12 12:01

20-Sep-12 12:01

Hard to say from that - we only have half the picture here. Tell you what, what do you see if you change the DataGridTemplateColumns into DataGridTextColumns? What appears in the text? Is the source correct then?

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Kevin Marois20-Sep-12 13:23

Kevin Marois

20-Sep-12 13:23

That did it. Thanks Pete

If it's not broken, fix it until it is

Pete O'Hanlon20-Sep-12 13:58