Question

This should be really easy, I just want to update the listview when the user adds something in the textbox to my observable collection.

I don’t understand why I can’t get this working:

XAML

<Window x:Class="MyStuff.WPF.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="486" Width="540" WindowStyle="SingleBorderWindow" ResizeMode="NoResize" >
    <Grid>
        <Menu IsMainMenu="True" VerticalAlignment="Top" HorizontalAlignment="Stretch" FlowDirection="LeftToRight">
            <MenuItem Header="File" >
                <MenuItem Header="Open File..">
                </MenuItem>
                <MenuItem Header="Exit">
                </MenuItem>
            </MenuItem>               
        </Menu>
        <TextBox Height="36" HorizontalAlignment="Left" Margin="12,27,0,0" Name="textBoxSearchTerm" VerticalAlignment="Top" Width="414" FontSize="24" MaxLength="80" AcceptsReturn="False" Background="#FFFFFFE8" Text="asdfasdf" FontWeight="Bold" FontFamily="Calibri" FontStretch="Normal" />
        <Button Content="Add" Height="36" HorizontalAlignment="Left" Margin="435,27,0,0" VerticalAlignment="Top" Width="68" FontSize="20" FontWeight="Normal" FontFamily="Calibri" Click="AddSearchTerm_Click" />

        <ListView Height="338" HorizontalAlignment="Left" Margin="12,97,0,0" Name="listView1" VerticalAlignment="Top" Width="261" ItemsSource="{Binding SearchTerms}">
        <ListView.View>
            <GridView>
                <GridViewColumn Width="120" Header="Search Term" DisplayMemberBinding="{Binding}" />
            </GridView>
        </ListView.View>
    </ListView>

    </Grid>
</Window>

Code Behind

public partial class MainWindow : Window
{
    public ObservableCollection<string> searchItems = new ObservableCollection<string>();

    public MainWindow()
    {
        InitializeComponent();
    }

    // DEFINE A PROPERTY..
    public ObservableCollection<string> SearchItems
    {
        get { return searchItems; }
    }

    private void AddSearchTerm_Click(object sender, RoutedEventArgs e)
    {
        searchItems.Add(textBoxSearchTerm.Text);
    }
}

Answer 1

Tigrans answer is correct with regards to setting the datacontext. This is required to do databinding. There are a number of ways this can be accomplished but the easiest way would be to set the datacontext to your viewmodel (SearchItems).

public MainWindow()
{
    InitializeComponent();
    this.DataContext = SearchItems;
}

Then your binding would look like <ListView ... ItemSource={Binding}>
Also you have {Binding SearchTerm} a couple times but i do not see a property that it would be binding to (maybe a typo).

Another option for binding the DataContext is to set it to the control itself:

this.DataContext = this;

This will change your binding expressions to {Binding Path=SearchItems} as this will tell the binding engine to look for the SearchItems property on the current datacontext.

Hope this helps.