Possibility to have Range data annotation validation only on form submit?

Question

I have been searching through the stackoverflow website for an answer to my question, but I couldn't find a proper solution. So I hope I can get the solution this way.

Situation: I have a form with several fields; 2 of them are required: one of them is an EnumDropDownListFor which has an extra 'empty option'.

Problem: The validation of the dropdownlist triggers on the change event of the dropdown/when the empty option has been selected.

Wanted behavior: Only validate the dropdownlist when the form is submitted and NOT on the change event.

Here is my code:

public class SearchOrderViewModel
{
    [Required]
    [Display(Name = "Supplier", ResourceType = typeof(SearchOrderStrings))]
    public string Supplier { get; set; }

    [Required]
    [Range(1, int.MaxValue, ErrorMessageResourceType = typeof(SearchOrderStrings), ErrorMessageResourceName = "OrderTypeRequired")]
    [Display(Name = "OrderType", ResourceType = typeof(SearchOrderStrings))]
    public OrderTypeEnum OrderType { get; set; }

    [Display(Name = "PurchasingReason", ResourceType = typeof(SearchOrderStrings))]
    public int PurchasingReason { get; set; }
}

public enum OrderTypeEnum
    {
        OpenOrder = 1,
        ClosedOrder = 2
    }

Index.cshtm

<div id="divExternalSupplierSearch" class="form-group">
    @Html.LabelFor(model => model.Supplier)
    @Html.ValidationMessageFor(model => model.Supplier)
    <div id="divDropdown">
        @Html.DropDownListFor(model => model.Supplier,
        Model.SupplierCodes, new { @class = "form-control" })
    </div>
</div>
<div id="divOrderTypes" class="form-group">
    @Html.LabelFor(model => model.OrderType)
    @Html.ValidationMessageFor(model => model.OrderType)
    <div id="divDropdown">
        @Html.EnumDropDownListFor(model => model.OrderType, new { @class = "form-control" })
    </div>
</div>
<div id="divPurchasingReasons" class="form-group">
    @Html.LabelFor(model => model.PurchasingReason)
    <div id="divDropdown">
        @Html.DropDownListFor(model => model.PurchasingReason, Model.PurchasingReasons, new { @class = "form-control" })
    </div>
</div>

If more information is needed, let me know.

Thanks

EDIT (Solution):

By combining @Elmer Dantas answer and trying some things, I found that I could become the wanted behaviour by removing the [Range] data-annotation and making the OrderType property in my SearchOrderViewModel nullable.

So this code is only validating the OrderType value on submit of the form:

[Required]
[Display(Name = "OrderType", ResourceType = typeof(SearchOrderStrings))]
public OrderTypeEnum? OrderType { get; set; }

Apparently the

[Range(1, int.MaxValue, ErrorMessageResourceType = typeof(SearchOrderStrings), ErrorMessageResourceName = "OrderTypeRequired")]

data-annotation was checking if the value was valid on the change event of the dropdownlist. By making the property nullable and just keeping the [Required] data-annotation, I could keep the validation to only be triggered when submitting the form.