Erro ao vincular componente dataGridView

protected void Button1_Click(object sender, EventArgs e)
        {
         
            SqlDataReader sqldr = null;
            SqlConnection con = null;
            SqlCommand cmd = null;

            try
            {
                string ConnectionString = "Data Source=SIDI06;Initial Catalog=dbIntranetAdm;Integrated Security=SSPI";
                con = new SqlConnection(ConnectionString);
                con.Open();
                
                string CommandText = "SELECT * " + "FROM exp_expenses_details " + "WHERE (expense_id LIKE @criterio)";
                
                cmd = new SqlCommand(CommandText);
                cmd.Connection = con;
                
                cmd.Parameters.Add(
                    new SqlParameter(
                    "@criterio",                                 
                    System.Data.SqlDbType.NVarChar, 
                    40,                                              
                    "expense_id"));

                cmd.Parameters["@criterio"].Value = TextBox4.Text + "%";
               
                sqldr = cmd.ExecuteReader();
                //lbDados.Items.Clear();

                int nColunas = sqldr.FieldCount;

                for (int i = 0; i < nColunas; i++)
                {
                    grdExpenses.Columns.Add(sqldr.GetName(i).ToString(), sqldr.GetName(i).ToString());
                }
                                
                string[] linhaDados = new string[nColunas];
                
                while (sqldr.Read())
                {
                    //lbDados.Items.Add(sqldr["expense_id"].ToString());

                    for (int a = 0; a < nColunas; a++)
                        {
                            if (sqldr.GetFieldType(a).ToString() == "System.Int32")
                            {
                                linhaDados[a] = sqldr.GetInt32(a).ToString();
                            }
                            if (sqldr.GetFieldType(a).ToString() == "System.String")
                            {
                                linhaDados[a] = sqldr.GetString(a).ToString();
                            }
                            if (sqldr.GetFieldType(a).ToString() == "System.DateTime")
                            {
                                linhaDados[a] = sqldr.GetDateTime(a).ToString();
                            } 
                        }
                        
                        grdExpenses.Rows.Add(linhaDados);                                                          
                }
            }
            catch (Exception ex)
            {
                ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "sua-mensagem", "alert(''Informe um número a procurar'')", true);
            }
            finally
            {
                
                if (sqldr != null)
                    sqldr.Close();
                if (con.State == ConnectionState.Open)
                    con.Close();
            }
        }