How to unselect (make default) combobox?

Question

WPF

There is some combobox, in the course of the program I select values ​​from the collection that I myself set.
When moving to the next stage, I want the combobox to become again without the selected element . The
Internet prompted for such a solution . Thus, going beyond the borders and removing the selection. BUT! This does not work in my program, because setting the index "-1" calls the function Through which I have the main operations, thus I can not use the above method. Maybe there is some other way?
combobox1.SelectedItem = -1;
comboBox1_SelectedIndexChanged

Answer 1

comboBox1_SelectedIndexChanged
if (combobox1.SelectedIndex == -1) return;