更改填充时ListViewItem的背景颜色

Question

this is tearing my hair out,

I have a listview

<ListView Canvas.Left="1045"  Canvas.Top="667"  FontSize="25" ItemsSource="{Binding Items}"   FontFamily="Gill Sans MT" Height="173" Name="lvContact" Width="536" SelectionChanged="lvContact_SelectionChanged">

In my code behind im dynamically adding an item to the list

public void UpdateContactList(Hashtable contactList)
{
    this.lvContact.Items.Clear();

    SortedDictionary<string,string> sortedContactList = new SortedDictionary<string,string>();


    foreach (DictionaryEntry de in contactList)
    {
        sortedContactList.Add(de.Key.ToString(), de.Value.ToString());
    }


    foreach (var de in sortedContactList)
    {
        System.Windows.Controls.ListViewItem contactItem = new System.Windows.Controls.ListViewItem();
        string contactItemString = de.Key.ToString();

        System.Windows.Controls.ListViewItem text = new System.Windows.Controls.ListViewItem();

        text.Content = contactItemString;
        if (de.Value == "NLN")
        {
            text.Background = Brushes.Green;
        }
        else
        {
            text.Background = Brushes.Gray;
        }
        lvContact.Items.Add(text);
    }
}

However the background color never changes and the list doesnt update.

Any ideas why ? Many thanks

Answer 1

ListViews can either be bound to an ItemsSource , or you can specify the ListView.Items manually. You cannot have both.

Your ListView definition binds your ListView.ItemsSource , so you cannot manually specify ListView.Items .

Since your ItemsSource is bound to a property Items , then I would assume you have a List<T> or ObservableCollection<T> somewhere called Items with the items for your ListView. To modify the ListView's Items, you should be modifying this collection.

To change the Background color based on a value, I would use a DataTrigger. This will allow you to keep your ItemsSource bindnig, and keeps your data separated from your UI.

<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="Background" Value="Gray" />
    <Style.Triggers>
        <DataTrigger Binding="{Binding Value}" Value="NLN">
            <Setter Property="Background" Value="Green" />
        </DataTriggers>
    </Style.Triggers>
</Style>