Populating a dropdown listbox problem!

How do I use my datareader object to populate a dropdownlistbox??? Im
getting conversion type errors..??????
here is the code

string myConnection = "........";
string mySelectQuery = "select employee_class_name from onlinetime_empclass
";
OleDbConnection myConn = new OleDbConnection(myConnection);
OleDbCommand objCommand = new OleDbCommand(mySelectQuery, myConn);
OleDbDataReader objDataReader = null;
myConn.Open();
objDataReader = objCommand.ExecuteReader();
string sEmployClass = "";
while (objDataReader.Read() == true)
    {
        *sEmployClass = objDataReader["employee_class_name"];
       ddemployeeClassification.Items.Add(sEmployClass);
}
I get an error when i try to view in a browsers:

*Compiler Error Message: CS0029: Cannot implicitly convert type 'object' to
'string'

You can read messages from the DOTNET archive, unsubscribe from DOTNET, or
subscribe to other DevelopMentor lists at http://discuss.develop.com.