// ------------------------------------------------------
//
// ISelectionProvider interface implementation
//
// ------------------------------------------------------
// Returns an enumerator over the current selection.
IRawElementProviderSimple[] ISelectionProvider.GetSelection()
{
int count = Length;
int countSelection = IsMultipleSelection() ? GetSelectionCount() : 1;
if (count <= 0 || countSelection <= 0)
{
return(null);
}
IRawElementProviderSimple[] selection = new IRawElementProviderSimple[countSelection];
int index = 0;
for (int itemPos = 0; itemPos < count; itemPos++)
{
if (ListboxItem.IsSelected(_hwnd, itemPos))
{
selection[index] = CreateListboxItem(itemPos);
index++;
}
}
if (index == 0)
{
return(null);
}
return(selection);
}
// Detect if there any selections in
// This is used by the WindowsListBoxItem class
// returns true if any items are selected
private bool HasSelection()
{
int i, count;
for (i = 0, count = Length; i < count && !ListboxItem.IsSelected(_hwnd, i); i++)
{
;
}
return(i < count);
}
// Detect if listbox has any element except skipItem selected
// This is used by the WindowsListBoxItem class
// returns true if any items
private bool HasOtherSelections(int skipItem)
{
for (int i = 0, count = Length; i < count; i++)
{
if (i != skipItem && ListboxItem.IsSelected(_hwnd, i))
{
return(true);
}
}
return(false);
}
private int GetOtherSelection(int skipItem)
{
for (int i = 0, count = Length; i < count; i++)
{
if (i != skipItem && ListboxItem.IsSelected(_hwnd, i))
{
// Win32 listbox items are 0 based, UIAutomation listbox items are 1 based.
return(i + 1);
}
}
return(NativeMethods.LB_ERR);
}
// Adds this element to the selection
void ISelectionItemProvider.AddToSelection()
{
// Check that control can be interacted with.
// This state could change anytime
if (!SafeNativeMethods.IsWindowEnabled(_hwnd))
{
throw new ElementNotEnabledException();
}
// check if item already selected
if (ListboxItem.IsSelected(_hwnd, _item) && !_listBox.IsParentedByCombo())
{
// if it is a combo, then always perform the selection otherwise the listbox won't disappear
return;
}
bool multipleSelection = _listBox.IsMultipleSelection();
// object does not support multi-selection
if (!multipleSelection)
{
IRawElementProviderSimple container = ((ISelectionItemProvider)this).SelectionContainer;
bool selectionRequired = container != null ? ((ISelectionProvider)container).IsSelectionRequired : true;
// For single selection containers that IsSelectionRequired == false and nothing is selected
// an AddToSelection is valid.
if (selectionRequired || _listBox.HasSelection())
{
throw new InvalidOperationException(SR.Get(SRID.DoesNotSupportMultipleSelection));
}
}
if (_listBox.IsParentedByCombo())
{
// if this is a combo and the listbox is not displayed the selection will not stick, so
// display the listbox before doing the select.
if (((IExpandCollapseProvider)_listBox._parent).ExpandCollapseState == ExpandCollapseState.Collapsed)
{
((IExpandCollapseProvider)_listBox._parent).Expand();
}
}
// At this point we know: Item either supports multiple selection or nothing
// is selected in the list
// Try to select an item
if (!Select(multipleSelection))
{
throw new InvalidOperationException(SR.Get(SRID.OperationCannotBePerformed));
}
}