Sql 通过参数调出结果时出错

我正试图通过一个下拉选择，其中有日期范围的选择，如今天，每周，每月，每年拉结果

protected void ddlFilter_SelectedIndexChanged(object sender, EventArgs e)
    {
        DateTime StartDate;
        DateTime? EndDate;

        if (ddlFilter.SelectedValue == "today")
        {
            //StartDate = Convert.ToInt32(ddlFilter.SelectedValue)
            StartDate = DateTime.Today;
            EndDate = DateTime.Today;
        }
        if (ddlFilter.SelectedValue == "weekly")
        {
            StartDate = DateTime.Today;
            EndDate = DateTime.Now.AddDays(-7).Date;
        }
        if (ddlFilter.SelectedValue == "byweekly")
        {
            StartDate = DateTime.Today;
            EndDate = DateTime.Now.AddDays(-15).Date;
        }
        if (ddlFilter.SelectedValue == "monthly")
        {
            StartDate = DateTime.Today;
            EndDate = DateTime.Now.AddMonths(-1).Date;
        }
        if (ddlFilter.SelectedValue == "yearly")
        {
            StartDate = DateTime.Today;
            EndDate = DateTime.Now.AddYears(-1).Date;
        }
        FillGridFilter(StartDate, EndDate);
    }

private void FillGridFilter(DateTime StartDate, DateTime? EndDate)
    {
        if (EndDate != null)
        {
            hdnid.Value = EndDate.ToString();
        }

        grdCrew.DataSource = null;
        DataTable dtbl = BIZ.ReportsBIZAdmin.ReportsCityFilter(StartDate, EndDate).Tables[0];

        if (dtbl != null && dtbl.Rows.Count > 0)
        {
            grdCrew.DataSource = dtbl;
            grdCrew.DataBind();
            ViewState["griddata"] = dtbl;
        }
        else
        {
            grdCrew.DataSource = null;
            grdCrew.DataBind();
            ViewState["griddata"] = null;
        }
    }

现在，它在

“FillGridFilter（StartDate，EndDate）；”

表示

使用未分配的局部变量“EndDate”

，

使用未分配的局部变量“EndDate”

及

表示“BIZ.ReportsBIZAdmin.ReportsCityFilter（System.DateTime，System.DateTime）”的最佳重载方法匹配项有一些无效参数

存储过程似乎工作正常，它是：

if @end_date = 'today' 
begin
    select jp.id, city.name[City]

    from rs_job_posting jp

    inner join rs_job_posting_location jpl on jpl.id = jp.id
    inner join rs_cor_city city on city.id = jpl.city_fk
    inner join rs_organization_detail od on od.id = jp.id

    where posting_date between '@start_date' and '@end_date'
    order by no_of_posts Desc 
END

---

因为

EndDate

可以为空，所以在声明它时必须为它赋值（甚至为空）

DateTime? EndDate = null;

至于第二个错误，您应该使用nullable的属性

Value

（您应该首先检查它是否有值）来获取

DateTime

对象：

if (EndDate.HasValue)
    DataTable dtbl = BIZ.ReportsBIZAdmin.ReportsCityFilter(StartDate, EndDate.Value).Tables[0];

---

问号是打字错误吗

private void FillGridFilter（DateTime StartDate，DateTime？EndDate）

。又学到了一些新的东西：）你是什么意思……请你解释一下……我不知道你可以像这样定义可为null的参数：）

if (EndDate.HasValue)
    DataTable dtbl = BIZ.ReportsBIZAdmin.ReportsCityFilter(StartDate, EndDate.Value).Tables[0];