Question

Any idea why the following dropdownlist won’t validate with required field as type int (the “Title” field below)?

    [Required]             // This works!
    [Display(Name = "Name")]
    public string Name { get; set; }

    [Required]             // This doesn't work 
    [Display(Name = "Title")]
    public int TitleId { get; set; }



     <div class="editor-label">
        @Html.LabelFor(model => model.Name, "Name")
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Name)
        @Html.ValidationMessageFor(model => model.Name, "This can't be blank!")
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.TitleId, "Title")
    </div>
    <div class="editor-field">
         @Html.DropDownListFor(model => model.TitleId, (SelectList)ViewBag.TitleId, String.Empty)
        @Html.ValidationMessageFor(model => model.TitleId)
    </div>

Answer 1

According to this work item, client-side validation breaks when the SelectList in the ViewBag uses the same name as the field in question. (i.e. both are TitleId in your case.)

Try this:

@Html.DropDownListFor(model => 
    model.TitleId, (SelectList)ViewBag.TitleIdList, String.Empty)

with your SelectList renamed to TitleIdList accordingly.