ExecuteReader- An exception of type 'System.InvalidOperationException' occurred in System.Data.dll but was not handled in user code

Question

I am getting the above mentioned error everytime I try to run this particular web page. I am adding some code and an image of the database structure (given as a link). In the additional information line of the error, it says there has been attempt to read data when the data table is empty. When I go back to check the table data, there is data present. Please help!

SqlConnection con = new SqlConnection(@"ConnectionString");
protected void Page_Load(object sender, EventArgs e)
{
    string checkdu = "select Top 1 Hour, Minute, Hour1, Minute1 from Clockin";
    SqlCommand cmddu = new SqlCommand(checkdu, con);
    con.Open();
    SqlDataReader dru = cmddu.ExecuteReader();
    int td1 = (Convert.ToInt16(dru["Hour"]) * 60) + (Convert.ToInt16(dru["Minute"]));      //error shown here[enter image description here][1]
    int td2 = (Convert.ToInt16(dru["Hour1"]) * 60) + (Convert.ToInt16(dru["Minute1"]));

Answer 1

You have to use SqlDataReader.Read to advance the reader to the next(first) record:

using(var dru = cmddu.ExecuteReader())
{
    if(dru.Read())
    {
        int td1 = (Convert.ToInt16(dru["Hour"]) * 60) + (Convert.ToInt16(dru["Minute"]));      //error shown here[enter image description here][1]
        int td2 = (Convert.ToInt16(dru["Hour1"]) * 60) + (Convert.ToInt16(dru["Minute1"]));
    }
}

Remarks :

The default position of the SqlDataReader is before the first record. Therefore, you must call Read to begin accessing any data.