Question

I have a two model classes which have relationship of one to many.

public class CycleType
{
    [Required(ErrorMessage = "Cycle is required.")]
    public int CycleTypeID { get; set; }

    [Required(ErrorMessage = "Cycle Type is required.")]
    [StringLength(20, ErrorMessage = "Cycle Type may not be longer than 20 characters")]
    public string Type { get; set; }

    public List<CycleModel> CycleModels { get; set; }
}

public class CycleModel
{
    public int CycleModelID { get; set; }

    [DisplayName("Cycle Type")]
    [Required(ErrorMessage = "Cycle is required.")]
    public int CycleTypeID { get; set; }

    [Required(ErrorMessage = "Model is required.")]
    [StringLength(20, ErrorMessage = "Model may not be longer than 20 characters")]
    public string Model { get; set; }

    public virtual CycleType CycleType { get; set; }
}

Razor file.

    <div class="editor-label">
        @Html.LabelFor(model => model.CycleTypeID)
    </div>
    <div class="editor-field">            
        @Html.DropDownListFor(model => model.CycleTypeID,
                                (SelectList)ViewBag.CycleType,
                                "Select Cycle Type",
                              new { id = "ddlCycleType" })
        @Html.ValidationMessageFor(model => model.CycleTypeID)
    </div>


    <div class="editor-label">
        @Html.LabelFor(model => model.Model)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Model)
        @Html.ValidationMessageFor(model => model.Model)
    </div>

1)Fist of my problem is, Validaion function did not fire when I choose select cycle type and it only give error back as

The ViewData item that has the key 'CycleTypeID' is of type 'System.Int32' but must be of type 'IEnumerable<SelectListItem>'.

2)Second problem is, When I choose one of the cycle type and put value to model more than 20 characters so that validator could check as I expected. But I get the same error message again.

The ViewData item that has the key 'CycleTypeID' is of type 'System.Int32' but must be of type 'IEnumerable<SelectListItem>'.

Every suggestion will be appreciated.

Answer 1

Well this is a bug in Asp.net MVC due to which the validations don’t work for DropDownListFor and TextAreaFor extension methods.

You can check the details at http://aspnet.codeplex.com/workitem/8576

So, you will need to make use of HTML.DropDownList instead of DropDownListFor and then your validations will work as expected.

Update

From your controller, pass this

ViewBag.CycleTypeId = new SelectList(db.CycleTypes, "CycleTypeId", "Type"); // db is ur context instance

And in View use this

@Html.DropDownList("CycleTypeId", String.Empty)

More Update

There is one more work-around for this problem.

Just use your original code of DropDownListFor. And then just make use of class property in it like following

 @Html.DropDownListFor(model => model.CycleTypeID,
                            (SelectList)ViewBag.CycleType,
                            "Select Cycle Type",
                          new { id = "ddlCycleType", @class = "required" })

This will make the validation work, but it will display the default message of The field is required. But else will work as you expect it to be.

I guess this is a better solution and good one for your requirements.