SelectListItem selected = true not working in view

Question

I have a gender select field (--Select--, Male, Female) and I\'m populating that in my controller. When the page loads, I want the gender that is selected in the model pm.

Answer 1

Method to get genders with select:

private Dictionary<string,string> GetGender(){
    Dictionary<string, string> myDic = new Dictionary<string, string>();
    myDic.Add(System.DBNull.Value.ToString(), "Select");
    myDic.Add("Male", "Male");
    myDic.Add("Female", "Female");
    return myDic;
}

In the controller:

//without selectedValue
ViewData["gender"]  = new SelectList(GetGender(), "Key", "Value");

OR

//"Male" as selectedValue
ViewData["gender"]  = new SelectList(GetGender(), "Key", "Value", "Male");

In the view:

Html.DropDownListFor(m => m.Gender, (SelectList)(ViewData["gender"]),
                        new { @class = "span2" })

Answer 2

Try this;

public static List<SelectListItem> ListSexo { get; } = new List<SelectListItem>
    {
        new SelectListItem{Selected =true, Value="N", Text="Seleccione"},
        new SelectListItem{Value="F", Text="Femenino"},
        new SelectListItem{Value="M", Text="Masculino"}
    };

<select asp-for="Sexo" asp-items="Commons.ListSexo" class="form-control"></select>

Answer 3

After searching myself for answer to this problem - I had some hints along the way but this is the resulting solution. It is an extension Method. I am using MVC 5 C# 4.52 is the target. The code below sets the Selection to the First Item in the List because that is what I needed, you might desire simply to pass a string and skip enumerating - but I also wanted to make sure I had something returned to my SelectList from the DB)

Extension Method:

public static class SelectListextensions
{

    public static System.Web.Mvc.SelectList SetSelectedValue
(this System.Web.Mvc.SelectList list, string value)
    {
        if (value != null)
        {
            var selected = list.Where(x => x.Text == value).FirstOrDefault();
            selected.Selected = true;                
        }
        return list;
    }    
}

And for those who like the complete low down (like me) here is the usage. The object Category has a field defined as Name - this is the field that will show up as Text in the drop down. You can see that test for the Text property in the code above.

Example Code:

SelectList categorylist = new SelectList(dbContext.Categories, "Id", "Name");

SetSelectedItemValue(categorylist);

select list function:

private SelectList SetSelectedItemValue(SelectList source)
{
   Category category = new Category();

    SelectListItem firstItem = new SelectListItem();

    int selectListCount = -1;

    if (source != null && source.Items != null)
    {
        System.Collections.IEnumerator cenum = source.Items.GetEnumerator();

        while (cenum.MoveNext())
        {
            if (selectListCount == -1)
            {
                selectListCount = 0;
            }

            selectListCount += 1;

            category = (Category)cenum.Current;

            source.SetSelectedValue(category.Name);

            break;
        }
        if (selectListCount > 0)
        {
            foreach (SelectListItem item in source.Items)
            {
                if (item.Value == cenum.Current.ToString())
                {
                    item.Selected = true;

                    break;
                }
            }
        }
    }
    return source;
}

You can make this a Generic All Inclusive function / Extension - but it is working as is for me.

Answer 4

I suggest it's better if you use strongly typed property for SelectList (rather than using ViewBag/ViewData). I believe what you are expecting is that your dropdownlist to be pre-selected with the gender selection made in the model. Here is a solution (code is not 100% clean. But this will work)

Model

public class TestModel
{
    public string Gender { get; set; }

    public IEnumerable<SelectListItem> GenderList
    {
        get
        {
            List<SelectListItem> list = new List<SelectListItem> { new SelectListItem() { Text = "Select", Value = "Select" }, new SelectListItem() { Text = "Male", Value = "Male" }, new SelectListItem() { Text = "Female", Value = "Female" } };
            return list.Select(l => new SelectListItem { Selected = (l.Value == Gender), Text = l.Text, Value = l.Value });
        }
    }
}

Controller Action

public ActionResult MyView()
{
    TestModel m = new TestModel();
    m.Gender = "Female";
    return View(m);
}

MyView.cshtml

@model TestModel

@{
    ViewBag.Title = "MyView";
}

<h2>MyView</h2>
@using (Html.BeginForm())
{
    <div>
          @Html.DropDownListFor(model => model.Gender, Model.GenderList)
    </div>
}

OUTPUT

dropdown with 'Female' option selected

EDIT

Based on comments find below links to sample projects

1) https://github.com/prashanth-t/DropdownDemo_BareBones (Using the MVC 4 empty template. Smaller file size with bare minimum)

2) https://github.com/prashanth-t/DropdownDemo (Using the MVC 4 internet application template. Bigger file size)

Answer 5

This is a known bug in ASP.NET MVC Razor View. As per the known bug documentation

"The reason behind this problem is that asp.net MVC first looks for a match between the name of the drop down and property on the model. If there’s a match, the selected value of the SelectList is overridden. Changing the name of the drop down is all it takes to remedy the issue."

I'm here giving a small example which you can use to test the resolution.

 var paymentTypeList = new List<SelectListItem>
                {
                    new SelectListItem { Text = "Select Payment Type", Value = "NA" },
                    new SelectListItem { Text = "Card", Value = "Card" },
                    new SelectListItem { Text = "Paytm Wallet", Value = "Paytm Wallet" },
                    new SelectListItem { Text = "Cash", Value = "Cash", Selected = true },
                    new SelectListItem { Text = "Credit", Value = "Credit" },
                    new SelectListItem { Text = "Other", Value = "Other" }
                };
 ViewBag.paymentTypeList = paymentTypeList;

Resolution Option 1 (Easiest) - Change the Name of declaration id of select list id in MVC view e.g

@Html.DropDownList("paymentTypeListNew", (List<SelectListItem>)ViewBag.paymentTypeList, new { @class = "form-control select2 select1" })

Resolution 2: (Use only single constructor of @Html.DropDownList that matches viewbag/viewdata property)

To ensure that selected item (cash in this example) gets selected do the following in MVC Razor View. Use only the following constructor without any CSS or new object values

 @Html.DropDownList("paymentTypeList") 

Now if you are worried that you cannot initialize the CSS then you need to initialize the css programitally. For example if you are using Jquery then can you can use

$("#paymentTypeList").addClass("form-control");
            $("#paymentTypeList").addClass("select2");

Answer 6

Try this instead in the controller:

string[] gender = new string[] {"Male", "Female"};
string selectedGender = gender.Where(x => x.StartsWith(pm.gender)).FirstOrDefault();
ViewData["gender"] = new SelectList(gender, selectedGender);

And in the view:

<%: Html.Dropdownlist(x => x.Gender, ViewData["gender"], "Select") %>