WPF datagrid column autocomplete

Question

Hello I need a help about datagrid in wpf. Actually I have C# experiences but new in WPF. I can answer my question in c# but don't know how to do this on WPF. I am using this code to solve datagridview cell autocomplete problem in c# and it works very good.

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    if(dataGridView1.CurrentCell.ColumnIndex == 7)
    {
        AutoCompleteStringCollection acBusIDSorce = new    AutoCompleteStringCollection();
        acBusIDSorce.Add("Autocomplete Value 1");
        acBusIDSorce.Add("Autocomplete Value 2");
        acBusIDSorce.Add("Autocomplete Value 3");

        TextBox txtBusID = e.Control as TextBox;

        if (txtBusID != null)
        {
            txtBusID.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
            txtBusID.AutoCompleteCustomSource = acBusIDSorce;
            txtBusID.AutoCompleteSource = AutoCompleteSource.CustomSource;
        }
    }
}

But I can't see EditingControlShowing Event in Wpf. How can i make this solution in WPF ? I searched many platforms but couldn't find anything

edit: I am populating my dataGrid with codebehind with this code

dataGrid1.ItemsSource=dt.DefaultView;