How Close SqlReader calling it in a function?

Question

4.50/5 (2 votes)

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I get this Error when call the page again:
There is already an open DataReader associated with this Command which must be closed first

C#

public static SqlDataReader FillGridView()
        {
            SqlCommand SqlCmd = new SqlCommand("SELECT * FROM MYTABLE");
            SqlCmd.Connection = conn;
            SqlCmd.CommandType = CommandType.Text;
            SqlDataReader SqlRd = SqlCmd.ExecuteReader();            
            return SqlRd;           
        }

Posted 10-Jun-11 5:12am

TheCodeVB

Updated 10-Jun-11 5:21am

Wayne Gaylard

v2

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3 solutions

Solution 1

This is not the way to use SQLDataReader:

SqlDataReader SqlRd = SqlCmd.ExecuteReader();
return SqlRd;

SQLDatareader is connected mode thing and thus you cannot just return it's instance without closing it.

Look here and read on how to use it:
Retrieving Data Using a DataReader (ADO.NET)[^]
SqlDataReader Class[^]

Posted 10-Jun-11 5:37am

Sandeep Mewara

Solution 3

This may help to you..
Better to use DataTable than the DataReader

public static DataTable FillGridView()
{
    DataTable dt = new DataTable();
    SqlCommand SqlCmd = new SqlCommand("SELECT * FROM MYTABLE",conn);
    SqlCmd.CommandType = CommandType.Text; // no need of this line it is by detault.
    try
    {
        conn.Open();
        dt.Load(SqlCmd.ExecuteReader());
        conn.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show("Error : "+ex.Message);
    }
    return dt;
}

Posted 11-Jun-11 2:11am

parmar_punit

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J a a n s · Accepted Answer · 2011-06-10T05:49:00

Solution 2

Use CommandBehaviour as a parameter for the ExecuteReader method. Also close the reader once the usage is over by calling the Close() method.

SqlDataReader SqlRd = SqlCmd.ExecuteReader(CommandBehaviour.CloseConnection);

Click here[^] for more details.

Posted 10-Jun-11 5:49am

J a a n s

Updated 10-Jun-11 5:51am

v2

Comments

TheCodeVB 10-Jun-11 14:08pm

With this parameter Works.