向 Datatable 函数添加参数

问：

我想在DataGridView中显示过程结果并从Combobox获取参数值

我创建了一个名为Report_with_depo

Create proc [dbo].[Report_with_depo]
@customer_id nvarchar (50)

AS
select customer_id ,customer_fullname, amount_withdraw ,amount_deposit ,entry_date
from Oprations b 
inner join Customers a
    on b.customer_id2 = a.customer_id
where customer_id = @customer_id

和数据表函数

public DataTable Report_with_depo()
{
    DAL.DataAccessLayer DAL = new DAL.DataAccessLayer();
    DAL.Open();
    DataTable dt = new DataTable();
    dt = DAL.SelectData("Report_with_depo", null);
    return dt;
}

显示按钮代码就像

this.dgv_Report.DataSource = Report_con.Report_with_depo();

我已经测试了我的代码并将参数替换为它有效的值，但现在我想从 Combobox 中获取值