I got this error "Invalid attempt to call Read when reader is closed" when I close dataReader inside While

Question

while (dr.Read())
                {
                    conn.Open();
                    string Qry = "SELECT COUNT(*) FROM tbl')";
                    SqlCommand com = new SqlCommand(Qry, conn);
                    int Cond = Convert.ToInt32(com.ExecuteScalar().ToString());
                    conn.Close();
                    if (Cond == 0)
                    {
                        //Do Some Actions
                    }
                    else
                    {
                        dr.Close();
                        myCon.Close();

                    }
                }

Answer 1

@Osama Abdelkader , If you want to get the count of the rows in the table, there is no need to use the SqlDatareader.

Here is a code example you could refer to.

Code:

        string connstr = "connstr";  
        SqlConnection connection = new SqlConnection(connstr);  
        connection.Open();  
        string comamnd = "select COUNT(*) from Student";  
        SqlCommand com = new SqlCommand(comamnd, connection);  
        int Cond = Convert.ToInt32(com.ExecuteScalar().ToString());  
        Console.WriteLine(Cond);  
        connection.Close();  

Hope the code example could help you. If I have some misunderstanding, Pleas feel free to let me know.

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Probably you should add a break after myCon.Close.

Or maybe you can use if instead of while.