Programmatically selecting Items/Indexes in a ListBox

Question

In WPF, I'd like to set the selected indexes of a System.Windows.Controls.ListBox

I best way I've found so far is to remove all the items from the control, insert the selected, call SelectAll(), then insert the rest, but this solution neither works in my situation nor is very efficient.

So, how do you set items in a Listbox to be selected, programmatically?

Naturally

Answer 1

One way you can do this is to add a Selected field to your data object. Then you need to overide the default listboxitem style and bind the isselected property to the Selected property in your object. Then you just need to go through your data items and update the Selected value.

If you don't implement that Selected property as a dependency property, you need your class to implented the INotifyPropertyChanged interface and raise the propertychanged event when you set the value.

Dulla

Thanks !...This worked fine. I'll just add a Code segment that I used below. – Farleigh

actually this is overcomplicated when compared to danlash's below. – Genaro

Answer 2

You can set multiple items as selected by using the SelectedItems collection. This isn't by index, but by what you have bound:

foreach (var boundObject in objectsBoundToListBox)
{
    ListBox.SelectedItems.Add(boundObject);
}

Macropterous

This will raise the SelectionChanged event once for each item added. When you select a group of items manually with shift it only gets raised once for the whole group. – Pia

Answer 3

You have to do this:

ListBoxObject.SelectedItem = ListBoxObject.Items.GetItemAt(itemIndex);

Where itemIndex would be the item you want to select. If you want to select multiple items, you need to use the ListBox.SelectedIndexCollection property.

Sawtelle

System.Windows.Controls.ListBox is not like System.Windows.Forms.ListBox in contining a SelectedIndexCollection property – Naturally

but not for mor than one item - and SelectedItems is read only – Sibylle

Answer 4

You can do this for multiple sections:

ListBoxObject.SelectedItems.Add(ListBoxObject.Items.GetItemAt(i));

Where i is the item index.

Fortdefrance

Answer 5

Thanks to mdm20. My case was actually checking a CheckBox within the ListBox, and this Dependency Property worked like a charm. I had to inherit my custom class from DependencyObject and implement the property

public class ProjectListItem : DependencyObject{ 

    public Boolean IsChecked
    {
        get { return (Boolean)this.GetValue(CheckedProperty); }
        set { this.SetValue(CheckedProperty, value); }
    }
    public static readonly DependencyProperty CheckedProperty =
        DependencyProperty.Register("IsChecked", typeof(Boolean), typeof(ProjectListItem), 
                                    new PropertyMetadata(false));
}

Farleigh

Answer 6

how to programmatically select multiple items in listbox in wpf

foreach (var boundObject in objectsBoundToListBox)
{
    ListBox.SelectedItems.Add(boundObject);
}

Schutzstaffel

Did you actually cut and paste this from danlash on this thread. – Hooded