Change means

ParentRow

                    TextColumn           CustomComboBoxColumn

Row1                TestX                              SelectedItem_X

Row2                TestY                              SelectedItem_Y

After collapsing and re-expanding

ParentRow

                    TextColumn           CustomComboBoxColumn

Row1                TestX                              SelectedItem_Y

Row2                TestY                              SelectedItem_X

Hi, 

Could you provide a little more details? 

Perhaps an example of how your data is laid out?

-SteveZ

Hi,

sorry. For example:

ObservableCollection<DemoData> Data contains

string PropA
double PropB
ObservableCollection<Car> PropC

Car contains

string Name { get; set; }
Equipment SelectedEquipment
ObservableCollection<Equipment> Equip

and ItemsSource of the XamGrid is Data

How do i bind Eqip to the Column ItemsSource?

Is Equipment going to be different for each Row?

-SteveZ

Unfortunately  yes.

Ok, so if equipment is going to be different for each row, you'll probably want to add another property to your column. 

Lets call it ItemsSourceMemberPath. 

Then you'll create a binding to the ComboBox's ItemsSource property and use that as the path:

Binding b = new Binding();

            b.Source = cell.Row.Data;

            b.Path = new PropertyPath(column.ItemsSourceMemberPath);

            this._combobox.SetBinding(ComboBox.ItemsSourceProperty, b);

You'd probably put this code in the ResolveDisplayElement method. 

Let me know if this works, 

-SteveZ

One thing is a bit ugly about the solution.

If you catch the event for the selection changing in the comboboxes it will be called several times with partly "wrong" data.

it works finally, thank you very much!

Hi, 

Ok, so comboBox and listBox can a bit of a pain to bind to in a recycling scenario, b/c SelectedItem and ItemSource are tied together. 

So, when you kill the DataContext for a row, which is expected b/c it's being recycled, the binding says, that the SelectedItem must not be valid anymore, and sets it to null. 

So.. with that said, you'll have to move some code around. 

First store off the cell binding in ResolveDisplayElement:

 _cellBinding = cellBinding;

Then move all your SetBinding logic to AdjustDisplayElement, like so:

public override void AdjustDisplayElement(Cell cell)

        {

            ComboBoxColumn column = (ComboBoxColumn)cell.Column;

            this._combobox.ClearValue(ComboBox.SelectedItemProperty);

            Binding b = new Binding();

            b.Source = cell.Row.Data;

            b.Path = new PropertyPath(column.ItemSourceMemberPath);

            this._combobox.SetBinding(ComboBox.ItemsSourceProperty, b);

            this._combobox.SetBinding(ComboBox.SelectedItemProperty, _cellBinding);

            base.AdjustDisplayElement(cell);

        }

Now, everything should work as expected. 

-SteveZ

I think the problem is, that the underlying content of a row is cleared after it is collapsed. Thats the reason why null is stored to SelectedEquipment. Therefore it is empty after expanding again. Is it possible to keep the content of the row?

I just took your last sample, followed your instructions and did this

  <igcc:ComboBoxColumn Key="SelectedEquipment" ItemSourceMemberPath="Equip" DisplayMemberPath="SeatName" Width="200" IsReadOnly="True" />

public override FrameworkElement ResolveDisplayElement(Cell cell, System.Windows.Data.Binding cellBinding)
{
ComboBoxColumn column = (ComboBoxColumn)cell.Column;

Binding b = new Binding();
b.Source = cell.Row.Data;
b.Path = new PropertyPath(column.ItemSourceMemberPath);
this._combobox.SetBinding(ComboBox.ItemsSourceProperty, b);

if (column.DisplayMemberPath != null)
this._combobox.SetValue(ComboBox.DisplayMemberPathProperty, column.DisplayMemberPath);

cellBinding.Mode = BindingMode.TwoWay;

this._combobox.SetBinding(ComboBox.SelectedItemProperty, cellBinding);

this._combobox.Style = cell.EditorStyleResolved;

return this._combobox;
}

ComboBoxColumn

/// <summary>
/// Identifies the <see cref="ItemSourceMemberPath"/> dependency property.
/// </summary>
public static readonly DependencyProperty ItemSourceMemberPathProperty = DependencyProperty.Register("ItemSourceMemberPath", typeof(String), typeof(ComboBoxColumn), null);

/// <summary>
/// Gets or sets a collection used to generate the content of the <see cref="ItemsControl"/>
/// </summary>
public String ItemSourceMemberPath
{
get { return (String)this.GetValue(ItemSourceMemberPathProperty); }
set { this.SetValue(ItemSourceMemberPathProperty, value); }
}