Question

here is code

    String[] month=new String[12]{"January","February","March","April","May","June","July","August","September","Octomber","November","December"};
    int day = DateTime.Now.Day;
    int mon= DateTime.Now.Month;
    mon = mon - 1;      //because month array is with 0
    Label1.Text = day.ToString();
    if (day==21)
    {
        int j = 1;
        SqlCommand cmd1 = new SqlCommand();
        cmd1.Connection = MyConn;
        cmd1.CommandText = "SELECT No_of_times,Dustbin_no from mounthly_data";
        SqlDataReader MyReader = cmd1.ExecuteReader();
        while (MyReader.Read())
        {
            String a = MyReader["No_of_times"].ToString();
            String b = MyReader["Dustbin_no"].ToString();

            SqlCommand cmd = new SqlCommand();
            cmd.Connection = MyConn;
            cmd.CommandText = "update Yearly_data set [" + month[mon] + "]='"+a+"' where Dustbin_no='"+b+"'";   //just see ["+month[mon+"] it's imp
            i = cmd.ExecuteNonQuery();    
        }
        MyReader.Close();
    }

i got error as

There is already an open DataReader associated with this Command which must be closed first.

Answer 1

I think you should give us the rest of the code above this code block because I’m not sure how a ExecuteNonQuery is using up a datareader. But from what I can gather, what you probably want is to open two separate connections. Only one datareader can be open per connection at a time. Either you use two separate connections or you could maybe use a datatable/dataset for the result of both your queries.

EDIT: From the rest of your code, yes, using two connections would be the simplest answer. When a reader is open, the connection associated with it is dedicated to the command that is used, thus no other command can use that connection.