如何在MVC的幫助下使用if else條件傳遞單個返回值？

Question

我創建了兩個過濾器搜索框，並在if else語句的幫助下將值傳遞給了控制器。 在我的if語句中，我創建了兩個單獨的條件以將返回值傳遞給視圖頁面。 對於兩種不同的條件，我只需要一個返回值。

public ActionResult ViewCompany(string Company, string City)
        {
            //View All Records
            var data = dp.Company.SqlQuery("Select * from CompanyRegistration ORDER BY CompanyID  DESC").ToList();
            //return View(dp.Company.Where(x => x.CompanyName.Contains(searching) || searching == null).ToList());

            //Search Function
            var customers1 = from s in dp.Company select s;
            if (Company != null || City != null)
            {
                if (!String.IsNullOrEmpty(Company))
                {
                    customers1 = customers1.Where(s => s.CompanyName.Contains(Company));
                    return View(customers1.ToList());
                }

                if (!String.IsNullOrEmpty(City))
                {
                    customers1 = customers1.Where(s => s.City.Contains(City));
                    return View(customers1.ToList());
                }
            }

            return View(data);
        }

csHTML頁面

@Html.BeginForm("ViewCompany", "Company", FormMethod.Get)
{
<div class="modal fade" id="upload3Modal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="modal-close" data-dismiss="modal" aria-label="Close">
                    <i class="font-icon-close-2"></i>
                </button>
                <h4 class="modal-title" id="myModalLabel">Search Company</h4>
            </div>
            <div class="modal-upload menu-big-icons">
                <div class="modal-upload-cont">
                    <div class="modal-upload-cont-in" style="border-left: none;">
                        <div class="tab-content">
                            <div role="tabpanel" class="tab-pane active" id="tab-upload-3-1">
                                <br />
                                <br />
                                Company Name: @Html.TextBox("Company")
                                <br />
                                <br />
                                City: @Html.TextBox("City")
                                <br />
                                <br />
                                <input type="submit" name="submit" value="Search" class=" btn btn-rounded btn-inline btn-success" />
                            </div><!--.tab-pane-->
                        </div><!--.tab-content-->
                    </div><!--.modal-upload-cont-in-->
                </div><!--.modal-upload-cont-->
            </div>
        </div>
    </div>
</div><!--.modal-->
}

Answer 1

你可以做：

var companies = from s in dp.Company select s;

if(!String.IsNullOrEmpty(Company)) companies = companies.Where(s => s.CompanyName.Contains(Company));

if(!String.IsNullOrEmpty(City)) companies = companies.Where(s => s.City.Contains(City));

return View(companies);

Answer 2

那這樣的事呢？

    public ActionResult ViewCompany(string Company, string City)
    {
        //View All Records
        var data = dp.Company.SqlQuery("Select * from CompanyRegistration ORDER BY CompanyID  DESC").ToList();
        //return View(dp.Company.Where(x => x.CompanyName.Contains(searching) || searching == null)).ToList());

        //Search Function
        var customers1 = from s in dp.Company select s;
        if (Company != null || City != null)
        {
            return !String.IsNullOrEmpty(Company) ?
                View(customers1.Where(s => s.CompanyName.Contains(Company)).ToList())
                : View(customers1.Where(s => s.City.Contains(City)).ToList());
        }

        return View(data);
    } 

編輯：

好的，我不明白您想要什么，請嘗試以下操作：

        if (Company != null || City != null)
        {
            if (!string.IsNullOrEmpty(Company))
            {
                customers1 = (!string.IsNullOrEmpty(City)) ?
                    customers1.Where(s => s.CompanyName.Contains(Company) && s.City.Contains(City))
                    : customers1.Where(s => s.CompanyName.Contains(Company));
            }

            if (!string.IsNullOrEmpty(City))
            {
                customers1 = (!string.IsNullOrEmpty(Company)) ?
                    customers1.Where(s => s.CompanyName.Contains(Company) && s.City.Contains(City))
                    : customers1.Where(s => s.City.Contains(City));
            }

            return customers1.ToList();
        }

Answer 3

我認為您根本不需要第一個if語句

public ActionResult ViewCompany(string Company, string City)
    {
        // Don't do redurant work

        //Search Function
        var customers = from s in dp.Company select s;
            if (!String.IsNullOrEmpty(Company))
            {
                customers = customers.Where(s => s.CompanyName.Contains(Company));
                return View(customers);
            }

            if (!String.IsNullOrEmpty(City))
            {
                customers = customers.Where(s => s.City.Contains(City));
                return View(customers);
            }

        return View(dp.Company.SqlQuery("Select * from CompanyRegistration ORDER BY CompanyID  DESC"));
    }

並將您的視圖模型簽名更改為IEnumerable而不是List 。 這是使用接口而不是其實現進行編碼的一種更好的方法。