Combobox selected item set on Loaded="UserControl_Loaded" event

Im working on WPF application, that passes a value from a listview on one page to the next page to have a combox pre selected when the page loads. But its not working.

the follow is a snippet of code within the UserControl_loaded event.

Right now the a1 and a2 are there for debugging to make sure there are some values and the right values being returned before setting the selected value / item /index neither of which work.

Should i be trying to do this under another event? can anyone help point me in the right direction.

thanks

            string a1 = string.Empty;
            string a2 = string.Empty;

            DataTable dtCaseInfo = dac.getCaseInfo(caseid);
            if (dtCaseInfo.Rows.Count > 0)
            {
                caseName = dtCaseInfo.Rows[0]["casename"].ToString();

                for( int i=0;i< cbCaseName.Items.Count ;i++){
                    if (cbCaseName.Items[i].Equals(caseName)) {
                        cbCaseName.SelectedIndex = i;
                    }
                }
                cbCaseName_SelectionChanged2();
                // cbCaseName.SelectedIndex  
                //cbCaseName.SelectedValue = caseName;
                //a1 = cbCaseName.SelectedValue.ToString();
                //a2 = caseid.ToString();
            }