How to open connection close and dispose in asp.netcC#

 

        string connString = @"your connection string here";
        string query = "select * from table";

        SqlConnection conn = new SqlConnection(connString);        
        SqlCommand cmd = new SqlCommand(query, conn);
        conn.Open();

        // create data adapter
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        // this will query your database and return the result to your datatable
        da.Fill(dataTable);
        conn.Close();
        da.Dispose();

ref:- https://stackoverflow.com/questions/6073382/how-to-read-sql-table-data-into-a-c-sharp-datatable