private void button20_Click(object sender, EventArgs e)//点击 后台总金
        {
            this.sqlConnection1.Open();
            SqlCommand sqlcon5 = new SqlCommand();
            sqlcon5.Connection = this.sqlConnection1;
             = "select Maccount from M_account";
            SqlDataReader dr = sqlcon5.ExecuteReader();
            while (dr.Read())
            {
                this.ATMMessagelistBox1.Items.Add(dr[0].ToString);
            }
            this.sqlConnection1.Close();

        }
這是ATM查詢金額的button 想實現在listbox顯示出來 但是有錯誤 幫忙看看

1：与“System.Windows.Forms.ListBox.ObjectCollection.Add(object)”最匹配的重载方法具有一些无效参数    

2：参数“1”: 无法从“方法组”转换为“object”