private void ComboBox_PreviewKeyDown(object sender, KeyEventArgs e)
{
var cb = sender as ComboBox;
if ((e.Key == Key.Return ||
e.Key == Key.Enter) &&
cb.Text != "")
{
bool duplicate = false;
foreach (ChildVM vm in MyVM.ChildVMCollection)
{
if (vm.Text == cb.Text)
{
cb.SelectedItem = vm;
duplicate = true;
break;
}
}
if (duplicate)
{
return;
}
// create a ChildM and corresponding ChildVM
// (ChildVM inherits from ChildM)
var cvm = new ChildVM()
{
Text = cb.Text
};
MyVM.ChildMCollection.Insert(0, cvm);
cb.SelectedItem = cvm;
}
}
private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var cb = sender as ComboBox;
//if (cb.SelectedItem is the VM with Style != Normal)
ChildVM foundVM = null;
foreach (ChildVM vm in MyVM.ChildVMCollection)
{
if (vm.Style != FontStyles.Normal &&
cb.SelectedItem == vm)
{
foundVM = vm;
break;
}
}
if (foundVM != null)
{
cb.Text = "";
e.Handled = true;
}
}
private void ChildMCollection_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
if (SynchDisabled)
{
return;
}
SynchDisabled = true;
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
foreach (object item in e.NewItems)
{
var vmItem = new ChildVM((ChildM)item);
// the operation could have been either Insert or Add
if (0 <= e.NewStartingIndex &&
e.NewStartingIndex <= ChildMCollection.Count)
{
ChildVMCollection.Insert(e.NewStartingIndex, vmItem);
}
else // e.NewStartingIndex < 0, so addition
{
ChildVMCollection.Insert(ChildMCollection.Count - 1, vmItem);
}
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (object item in e.OldItems)
{
// find VM objects that wrap the relevant model object and remove them
IEnumerable <ChildVM> query;
while ((query = from vm in ChildVMCollection
where vm.Text == ((ChildM)item).Text
select vm).Count() > 0)
{
ChildVM vmItem = query.First();
int index = ChildVMCollection.IndexOf(vmItem);
ChildVMCollection.Remove(vmItem); // TODO: what if I implement the == or != operator?
}
}
break;
case NotifyCollectionChangedAction.Reset:
for (int i = ChildVMCollection.Count - 2; i >= 0; --i)
{
ChildVMCollection.RemoveAt(i);
}
break;
case NotifyCollectionChangedAction.Move:
// TODO: handle multiple items
ChildVMCollection.Move(e.OldStartingIndex, e.NewStartingIndex);
break;
case NotifyCollectionChangedAction.Replace:
// TODO: handle multiple items
ChildVMCollection[e.OldStartingIndex] = new ChildVM((ChildM)e.NewItems[0]);
break;
default:
throw new NotImplementedException();
}
SynchDisabled = false;
}
