@model object
@{
    Type tModel = ViewData.ModelMetadata.ContainerType.GetProperty(ViewData.ModelMetadata.PropertyName).PropertyType;
}
@if(typeof(string).IsAssignableFrom(tModel)) {
    @Html.DevExpress().TextBoxFor(m => m).GetHtml();
}
else if(typeof(Enum).IsAssignableFrom(tModel)) {
    Html.DevExpress().ComboBoxFor(m => m, s => {
        s.Properties.Items.AddRange(Enum.GetValues(tModel));
        s.SelectedIndex = 0;
        s.Properties.DropDownStyle = DropDownStyle.DropDownList;
    }).GetHtml();
}