how can i solve this problem. The dt have fiften records out of which 10 have null value
<p>how can i get  list of students with values in it. I can not write in select query to retrieve, actually for dataset i will be calling method which returns all students</p>

<pre><code>   public IEnumerable GetCallingCodes()
    {
        DataSet ds = DataOps.GetDataSet(string.Format(" select * from students"));
       // foreach 


        DataTable dt = ds.Tables[0];

        List&lt;string&gt; retVal = new List&lt;string&gt;();

        foreach (DataRow row in dt.Rows)
        {
           if (row["address"]!=null)
       // line above is not ab
            { retVal.Add((string)row["student"]); }
        }
        return retVal;
</code></pre>
