C #-, design a Windows application to implement different operations.

Using system; using system. collections. generic; using system. componentmodel; using system. data; using system. drawing; using system. LINQ; using system. text; using system. windows. forms; namespace windowsformsapplication1 {public partial class form1: FORM {public form1 () {initializecomponent ();} private void combobox1_selectedindexchanged (Object sender, eventargs E) {} private void form1_load (Object sender, eventargs e) {combobox1.items. add ("+"); combobox1.items. add ("-"); combobox1.items. add ("*"); combobox1.items. add ("/"); combobox1.selectedindex = 0;} private void button#click (Object sender, eventargs e) {If (combobox1.text = "+") {Double X = double. parse (textbox1.text); Double Y = double. parse (textbox2.text); textbox3.text = (x + y ). tostring ();} If (combobox1.text = "-") {Double X = double. parse (textbox1.text); Double Y = double. parse (textbox2.text); textbox3.text = (x-y ). tostring ();} If (combobox1.text = "*") {Double X = double. parse (textbox1.text); Double Y = double. parse (textbox2.text); textbox3.text = (x * Y ). tostring ();} If (combobox1.text = "/") {Double X = double. parse (textbox1.text); Double Y = double. parse (textbox2.text); textbox3.text = (x/y ). tostring ();}}}}