c# - WPF Send combox's selected value to another window's identical combobox -

i have window @ startup select interface , port 2 comboboxs. when click done, takes main window, can see 2 more comboxes identical. these have selected values picked in popup window. can in code behind?

here's popup window, winresetinterface.xaml:

window x:class="simpliphy.winresetinterface"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     title="winresetinterface" height="280" width="259"> <grid margin="0,-1,2,1">     <combobox name="cmbinterface" itemssource="{binding interface}" displaymemberpath="name" horizontalalignment="left" margin="94,52,0,0" verticalalignment="top" width="91"/>     <button x:name="btnfinishsetup" click="btnfinishsetup_click" content="done" horizontalalignment="left" margin="76,173,0,0" verticalalignment="top" width="75"/>    <combobox x:name="cmbport"  itemssource="{binding selecteditem.port, elementname=cmbinterface}" horizontalalignment="left" margin="94,88,0,0" verticalalignment="top" width="91"/> </grid> 

and in code behind:

     namespace project     {          public partial class winresetinterface : window         {             public observablecollection<model.device_class> interface { get; set; }                  public winresetinterface()                 {                    initializecomponent();                    datacontext = this;                    interface = new observablecollection<model.device_class>();                    interface.add(new device_class() { name = "xgbe", port = new observablecollection<string>() { "0" } });                    interface.add(new device_class() { name = "sata0", port = new observablecollection<string>() { "0", "1", "2", "3" } });                  }           }          private void btnfinishsetup_click(object sender, routedeventargs e)         {             mainwindow main = new mainwindow();             app.current.mainwindow = main;             this.close();             main.show();              //set selected options on device stats sidebar             ///this i'm stuck!             main.cmbinterface_main.selecteditem = cmbinterface.selecteditem;           }     } 

in mainwindow, have combobox filled same way box1, cmbinterface. can not set 2 selecteditems equal each other?

you this:

main.cmbinterface_main.selectedindex = cmbinterface_main.findstringexact(cmbinterface.text, 0); 

although loopedcode's comment better answer.