SharePoint sets the value of the lookup field

How to set the value of the lookup field, first we also need to understand spfieldlookupvaluecollection and Spfieldlookupvalue, The principles of these 2 classes are as spfielduservaluecollection as they were previously explained, and are not explained much here.

1         /// <summary>2         ///Convert dropdownList value to Spfieldlookupvalue3         /// </summary>4         /// <param name= "DropdownList" >DropDownList Control</param>5         /// <returns>Spfieldlookupvalue</returns>6         Privatespfieldlookupvalue setlookupvalue (DropDownList DropDownList)7         {8Spfieldlookupvalue LookupValue =NewSpfieldlookupvalue (Convert.ToInt32 (dropdownList.SelectedItem.Value), dropdownList.SelectedItem.Text);9             returnLookupValue;Ten}

SharePoint sets the value of the lookup field