Why ItemContainerGenerator.ContainerFromIndex() returns null and how to avoid this behavior?

Question

I'm using this snippet to analyze the rows I've selected on a datagrid.

for (int i = 0; i < dgDetalle.Items.Count; i++)
{
    DataGridRow row = (DataGridRow)dgDetalle.ItemContainerGenerator.ContainerFromIndex(i);
    FrameworkElement cellContent = dgDetalle.Columns[0].GetCellContent(row);
    // ... code ...
}

The cycle runs smoothly, but when processing certain indexes, the second line throws a null exception. MSDN's documentation says that ItemContainerGenerator.ContainerFromIndex(i) will return null if 'if the item is not realized', but this doesn't help me to guess how could I get the desired value.

How can I scan all the rows? Is there any other way?

UPDATE

I'm using this snippet to read a CheckBox as explained here. So I can't use binding or ItemSource at all unless I change a lot of things. And I cannot. I'm doing code maintenance.

Answer 1

Try this,

DataGridRow row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromIndex(index);
        if (row == null)
        {
                          grid.UpdateLayout();
            grid.ScrollIntoView(grid.Items[index]);
            row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromIndex(index);
        }