WPF - ListView Extension with Inspect and Select ListViewItems
I have already read many examples on extending ListViews with checkboxes associated with IsSelected. But I want something else.
I want separation between checked and selected state, so I end up with a ListBox that has one selected item, but can have multiple checked items. Unfortunately the ListViewItem does not have a property to check, and I see no way to get the ListView to work with a custom CheckableListViewItem.
Of course, I could use a Checked Object List as the ItemSource, but I don't think that is a good way. Checked or not, it is a matter of the list or item container, not the object specified in it. Also, I don't want all my classes like user, role, group to have counterparts like checkableUser, checkableRole and checkableGroup.
The behavior I want can be easily complicated for the UI with
<DataTemplate x:Key="CheckBoxCell">
<StackPanel Orientation="Horizontal">
<CheckBox />
</StackPanel>
</DataTemplate>
and a
<GridViewColumn CellTemplate="{StaticResource CheckBoxCell}" Width="30"/>
But without binding to a checkbox, I cannot check if it is checked or not.
Is there a way to do something like this? An ideal solution for me would be to have listView1.SelectedItem, listView1.CheckedItems and possibly listView1.UncheckedItems and of course listView1.CheckItem and listView1.UncheckItem.
Thanks for any help.
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OK I understood. There wasn't much to do, but since I'm new to all WPF stuff, it was some work to figure out. Here's the solution:
public class CheckableListViewItem : ListViewItem
{
[Category("Appearance")]
[Bindable(true)]
public bool IsChecked { get; set; }
}
public class CheckableListView : ListView
{
public IList CheckedItems
{
get
{
List<object> CheckedItems = new List<object>();
for (int i=0;i < this.Items.Count; ++i)
{
if ((this.ItemContainerGenerator.ContainerFromIndex(i) as CheckableListViewItem).IsChecked)
CheckedItems.Add(this.Items[i]);
}
return CheckedItems;
}
}
public bool IsChecked(int index)
{
if (index < this.Items.Count) return (this.ItemContainerGenerator.ContainerFromIndex(index) as CheckableListViewItem).IsChecked;
else throw new IndexOutOfRangeException();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
if (item is CheckableListViewItem) return true;
else return false;
}
protected override DependencyObject GetContainerForItemOverride()
{
return new CheckableListViewItem();
}
}
Paste in your XAML under Window.Resources (clr = class namespace):
<DataTemplate x:Key="CheckBoxCell">
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding Path=IsChecked,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type clr:CheckableListViewItem}}}" />
</StackPanel>
</DataTemplate>
And this is how your CheckableListView:
<clr:CheckableListView SelectionMode="Single" [...] >
<ListView.View>
<GridView>
<GridViewColumn CellTemplate="{StaticResource CheckBoxCell}"
Width="30"/>
[...]
</GridView>
</ListView.View>
</clr:CheckableListView>
Maybe it helps someone with the same problem.
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To do this, you will need to create custom elements ListBox
and a custom ListBoxItem
to use in your application. Otherwise, you will have to add it to the items in your lists as a generic object ICheckable<T>
(where T is a user or role) and have it ICheckableCollection<ICheckable<T>>
for your items, rather than add model objects to check.
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