Object reference not set to an instance of an object.

Question

 This is my code:

 

protected void txtcmd_Click(object sender, EventArgs e)

{

         SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["connect"].ConnectionString);

         SqlCommand cmd = new SqlCommand();

         int ID = int.Parse(Session["Id"].ToString());

         string comments = ((TextBox)statusgrdview.FindControl("txtcommt")).Text;

         cmd.CommandType = CommandType.Text;

         cmd.CommandText = "insert into TBL_Comments(ID,comments) " + "values("+ID+",@comments);" + "select * from TBL_Comments";

         cmd.Parameters.Add("@comments", SqlDbType.VarChar).Value = comments;

         statusgrdview.DataSource = GetData(cmd);

         statusgrdview.DataBind();

}

private object GetData(SqlCommand cmd)

{

   throw new NotImplementedException();

}