How can I put combobox in editing mode from code

See more:

WPF

C#3.5

DataGrid

Hi,

I'm working on a datagrid including most combobox (DataGridComboBoxColumn) and one DataGridTextColumn.

I'll like to use this datagrid like a worksheet to be completed without using mouse "on kilometer typing"
I'm using combo only to validate typing

First, I clic on first combo, It go an edit mode (where I can type with keyboard without select with keu)
On tabkey, I go to the second combobox (who's too in edit mode)
and so on...

Problem :
I put an isediting order when I lost focus on a line and get it on next line
When I get out a line and pass to the new line, the first combo seems to be in edit mode (it's bordered) but I need to type again tabkey to put it really in edit mode.

What can I do to put whis combobox immediatly in edit mode ?

Think's a lot for your help.