Problems binding Silverlight DataGrid after updating or installing selectedIndex = -1

Question

I have datagrid and combobox in form. The combobox is attached to the selected datagrid element.

I load everything in order, and if I select different lines, then combobox is updated accordingly.

If, however, I set datagrid.selectedIndex = -1 after loading (so the first row is not selected), the combobox binding no longer works. This is problem.

I also have another scenario where the exact thing happens. If I filter the datagrid, combobox binding also stops working.

I bind a datagrid to a CollectionViewSource as shown below, where _codes is an ObservableCollection

_ocvsCode = (CollectionViewSource) this.Resources ["cvsCode"]; _ocvsCode.Source = _codes; dataGrid1.ItemsSource = _ocvsCode.View;
Code>

I don't know why binding to combobox fails after some operation on a datagrid.

Answer 1

The appropriate solution in this case is to bind the datagrid selecteditem to some variable and then bind other controls to this variable. It is generally a bad practice to associate UIElement properties directly with other UIElement properties. This will also debug the issue, which you seem to encounter forcing the selecteditem property in the combo box.

Answer 2

, ComboBox SelectedItem DataGrid.

ComboBox , . , , , . DataGrid , SelectedItem null, SelectedItem . SelectedItem , ComboBox .

:

SelectedItem , DataContext. , null. DataGrid ComboBox.

public YourItem SelectedItem
{
    get { return _selectedItem; }
    set
    {
        if (value == _selectedItem || value == null)
            return;

        _selectedItem = value;
        RaisePropertyChanged("SelectedItem");
    }
}