Bind lookup field data to the dropdownlist

Below code will help you to bind the lookup field data to the dropdown list.

if (spListItem["LookupField"] != null) {   SPFieldLookupValue spv = new      SPFieldLookupValue(spListItem["LookupField"].ToString());   string lookupValue = spv.LookupValue;   dropdownlist1.SelectedIndex = spv.LookupId;  }

 To bind field values to the dropdownlist:

dropdownlist1.SelectedValue = spListItem["Field1"].ToString();