Binding array to ListBox WPF

Hi, I'm currently messing around with WPF and I can't seem to get this done right. I'm trying to bind a string array to a ListBox, but when I run the program, the ListBox is empty.

public Window()
{
    string[] names = { "foo", "soo", "too" };
   
    listBox.ItemsSource = names;
}

If I do this:

public Window()
{
    string[] names = { "foo", "soo", "too" };
   
    listBox.ItemsSource = names;
    listBox.DisplayMemberPath = "Length";
}

then the ListBox displays 3,3,3.

How do I get the ListBox to  display the strings.

Thanks.

Your first code snippet can actually do the trick.

Sheva

Don't put your code in the constructor, or it might run before the InitializeComponent() call that sets up the WPF controls from your XAML.

You could use the Loaded event.

MyPage.xaml:
<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="WPF1.MyPage"
  Loaded="MyPage_Loaded">
    <ListBox Name="listBox">
  </ListBox>
</Page>

MyPage.xaml.cs:
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;

namespace WPF1
{
  public partial class MyPage : System.Windows.Controls.Page
  {
    public MyPage()
    {
      InitializeComponent();
    }

    void MyPage_Loaded(object sender, RoutedEventArgs e)
    {
      string[] names = { "foo", "bar", "xyzzy" };
      listBox.ItemsSource = names;
    }
  }
}

The right way to do it is by using Binding

<Window.Resources>

<ObjectDataProvider x:Key="data" ObjectType="{x:Type l:MyNames}"/>

</Window.Resources>

<StackPanel>

<ListBox ItemsSource="{Binding Source={StaticResource data}}"/>

-----------------

public class MyNames : List<string>

{

public MyNames()

{

this.Add("foo");

this.Add("soo");

this.Add("too");

}

}

But you also can show you string array in the listbox this way

<ListBox Name="list"/>
------------------

public Window1()

{

InitializeComponent();

list.Loaded += new RoutedEventHandler(list_Loaded);

}

string[] names = { "foo", "soo", "too" };

void list_Loaded(object sender, RoutedEventArgs e)

{

list.ItemsSource = names;

}

tamir wrote:

The right way to do it is by using Binding

Correction:  that's the declarative way to do it, not the "right" way.

The "right" way, I mean is to use Binding instead of regular reference

tamir wrote:

The "right" way, I mean is to use Binding instead of regular reference

   It depends on the type of scenario you wanna enable, if you simply show the data, assign the source collection directly to ItemsSource should be more appropriate, since it doesn't incur the performance implication which binding brings.
   If you wanna enable notification from data source to the UI element, then Binding should be the right way to do it.

Sheva

It's really hard for me to imagin, that I need only to show someting. If I do not want it to be updated, when the source changes, put it into resources or use directly in markup (e.g. state options). For all other cases (when you need to set this information from code-behind), you might want to bind to data, to be sure it'll be updated on source update

tamir wrote:

It's really hard for me to imagine, that I need only to show someting.

Standard operating procedure for reporting, which is typically read-only data binding.

JChung2006 said:

Don't put your code in the constructor, or it might run before the InitializeComponent() call that sets up the WPF controls from your XAML.

You could use the Loaded event.

MyPage.xaml:
<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="WPF1.MyPage"
  Loaded="MyPage_Loaded">
    <ListBox Name="listBox">
  </ListBox>
</Page>

MyPage.xaml.cs:
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;

namespace WPF1
{
  public partial class MyPage : System.Windows.Controls.Page
  {
    public MyPage()
    {
      InitializeComponent();
    }

    void MyPage_Loaded(object sender, RoutedEventArgs e)
    {
      string[] names = { "foo", "bar", "xyzzy" };
      listBox.ItemsSource = names;
    }
  }
}

void list_Loaded(object sender, RoutedEventArgs e)

{

list.ItemsSource = names;

}

/*I want to add one more line */

void list_Loaded(object sender, RoutedEventArgs e)

{

list.ItemsSource = names;

list.Items.Add("Happy"); /* Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead.*/

}

hi all I want to add some more Item after set Itemsource can u help me how to add after Set Itemsoure please Help me out

 

 

Thanks and regards

HAPPY

@tamir:Hi!

I read your answer and have some questions (maybe not too smart )

I have Visual Studio 2008, NET Framework 3.5/SP1

<ObjectDataProvider x:Key="data" ObjectType="{x:Type l:MyNames}"/>

1. Should I use x:Name instead of x:Key ?

2. What is "I:" here? I couldn't find such namespace in your code. I can't find the right namespace namу for me to compile such code

3. The main question. I have class:

 

public class A
{
private readonly string _name;
public A(string n)
{
_name = n;
}
public ShowName
{
get {return _name;}
}

public DoSmth
{
// Do something
}

I want to render list of class A objects as TextBlock with ShowName as text, and button wich will call DoSmth for this object. How can I do it?

Now I am trying something like this:

                <StackPanel x:Name="spLstOfA">
                    <ListBox Grid.Row="0" x:Name="lstOfA">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <StackPanel Orientation="Horizontal">
                                    <TextBlock Text="{Binding Path=ShowName}" />
                                    <Button Command="{Binding Path=DoSmth}" >Button!!</Button>
                                    
                                </StackPanel>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>
                </StackPanel>

P/s I am not familiar with WPF

@pivoo: You're almost there. You just need to set the ItemsSource property of the ListBox to your list of A objects. While there are other ways to do this, the easiest way is to set it in the code-behind during the Initialized event.

To answer your other questions:

1. No, this line goes in the <Window.Resources> section, so a key is needed.

2. You'll need to add a namespace to reference your assembly. <xmlns local="clr-namespace:MyAssembly"> will let you reference your own classes in XAML by prefixing them with local, such as <local:A>.

 

I think you'd benefit greatly by getting a book on WPF. I found Apress' "Pro WPF in C# 2008" to be very helpful. I'm sure there's an updated edition now for .NET 4.