Data reader error

[magic987654]

SqlConnection con = new SqlConnection(cn.getcon());
            if (con.State == ConnectionState.Open)
                con.Close();
            con.Open();
            SqlCommand cmd;
            SqlCommand cmd1;
            SqlDataAdapter dr1;
            SqlDataAdapter dr;  
            cmd = new SqlCommand("select * from sabha00a where s00a0004<='" + A00D0001.Value.ToString("yyyy-MM-dd") + "'",con);
            dr=cmd.ExecuteReader();
            while (dr.Read())
            {
                cmd1 = new SqlCommand("select * from milka00b where a00b0002=" + dr[0].ToString() + "",con);
                dr1 = cmd1.ExecuteReader(); 
            }
            con.Close();

//--------------------------------------------------------------------


Exception := Datareader already opened

I found this error in while loop. Please give me the solution for this error...

[tlhintoq]

TIP: When you first created your question you were asked to wrap your code with [code] tags.

It really does help a bunch. Look how much easier it is to read now that someone has done it for you. Its the button with a '#' on it. More on tags. They're cool. Check'em out.

[tlhintoq]

if (con.State == ConnectionState.Open) con.Close();
            con.Open();

I'm out of my element here but if I had to guess it is because you are making an assumption. Just because you order a con.Close() you assume it actually happens. What if it doesn't for some reason? You are not checking for the possibility of a less than perfect world.

if (con.State == ConnectionState.Open)   con.Close();
if (con.State == ConnectionState.Open)
{
   MessageBox.Show("Unable to close connection", "Error", MessageBoxButtons.Ok, MessageBox.Icon.Error);
}
            con.Open();

[jkmyoung]

you probably want:
if (con.State != ConnectionState.Close) con.Close();

Don't forget there are more states than just open and close.

See: http://msdn.microsoft.com/en-us/libr...v=VS.100).aspx
You were probably in fetching mode, or another state.