ASP.NET MVC Filter data according to the options selected in the drop-down list

Question

I'm new to this whole MVC world, please excuse me if the problem is simple.

I'm trying to is build a project that can let the user should be able to select the field to search in (LastName, FirstName, Department, and Location) using a drop-down list. And the user can type the search term in a text box and clicks the Search button. (Filter data according to the options selected in the drop-down list, and then enter the content that matches the options selected in the drop-down list)

The problem is: I can only search in a field, and the value in my drop-down list cannot be read by the text box.

My model is this:

public class Employee
    {
        public int EmployeeId { get; set; }

        [Required]
        [StringLength(50, MinimumLength = 1)]
        public string LastName { get; set; }

        [Required]
        [StringLength(50)]
        public string FirstName { get; set; }

        [Required]
        public string Department { get; set; }

        [StringLength(50)]
        public string Location { get; set; }
    }

My Controller is this:

public ActionResult Index(string sortOrder, string searchString)
        {
            ViewBag.EmployeeList = new List<SelectListItem>
            {
                new SelectListItem{Selected=true, Text="LastName", Value="LastName" },
                new SelectListItem{Selected=true, Text="FirstName", Value="FirstName" },
                new SelectListItem{Selected=true, Text="Department", Value="Department" },
                new SelectListItem{Selected=true, Text="Location", Value="Location" },
            };

            var employee = from e in db.Employee
                           select e;

            if (!String.IsNullOrEmpty(searchString))
            {
                employee = employee.Where(s => s.FirstName.Contains(searchString));
            }
            return View(employee);
        }

And my View is this:

<p>
        All: @Html.DropDownList( "EmployeeList");
        Search By: @Html.TextBox("searchString")<br />
        <input type="submit" value="Search">
    </p>

I don't know how can I use the drop-down list to select the corresponding field and let the search box search. For example, if I select "Location", I can enter some keywords about "Location" in the text box to search, but it is limited to Location, not FirstName or others

Answer 1

This is the controller where selectOption and searchtext are passed from the View

  public ActionResult Index(string SelectOption, string SearchText)
    {

        var model = from s in db.Employee
                    select s;

        if (!String.IsNullOrEmpty(SearchText) )
        {
            switch (SelectOption)
            {
                case "Email":
                    model = model.Where(a => 
a.Email.ToLower().Contains(SearchText.ToLower()));
                    break;

                case "Forname":
                    model = model.Where(a => 
a.Forename.ToLower().Contains(SearchText.ToLower()));
                    break;

                case "Surname":
                    model = model.Where(a => 
a.Surname.ToLower().Contains(SearchText.ToLower()));
                    break;

            }
        }
       



        return View(model.ToList());
    }

As for the view, you do need to use viewbag all the time for dropdownlist. Sometimes pure plain html can do a better job.

@model IEnumerable<Incendo.Entities.Employee>

@{
ViewBag.Title = "Index";
}

<h2>Index</h2>

@using (Html.BeginForm())
{

<label for="selectoption">Select Option:</label>
<select id="SelectOption" name="SelectOption">
    <option value="Email">Email</option>
    <option value="Surname">Surname</option>
    <option value="Forename">Forename</option>
</select>

<br />

@Html.Label("Search Text")
@Html.TextBox("SearchText") 
<input type="submit" value="Search" />
}


<table class="table table-responsive">
@foreach (var item in Model)
{
    <tr>
        <td>@item.Forename </td>
        <td>@item.Surname </td>
        <td>@item.Email  </td>
    </tr>
}

Finally, please remember to change the model reference to your own namespace