问C#：当字段不为空时是否返回IEnumerable？

EN

DataRow[] dr = ds.Tables[0].Select("Address NOT NULL"); // you want filtering on address column
    foreach (DataRow row in dr)
    {

    }

    private IEnumerable<Student> GetAddress()
        {
            DataSet ds = DataOps.GetDataSet(string.Format(" select * from Students Where NOT NULL [address]"));
            DataTable dt = ds.Tables[0];


            foreach (DataRow row in dt.Rows)
            {
                yield return new Student   
                                      {                                        
                                          StudentName = row["StudentName "].ToString(),
                                          Address= row["Address"].ToString()
                                      };
            }

        }

public IEnumerable GetAddress()
{
    DataSet ds = DataOps.GetDataSet(string.Format(" select * from Students"));
    DataTable dt = ds.Tables[0];

    // The chances are that instead of string you will need a struct or a class
    List<string> retVal = new List<string>();
    foreach (DataRow row in dt)
    {
        // This will obviously depend on the table and return type
        retVal.Add((string)row["mycol"]);
    }
}