Simpler forms

gistfile1.cs

// CreateEdit.cshtml
@using (Html.BeginForm("Create", "Licenses", FormMethod.Post, new {role = "form"}))
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true, "", new {@class = "text-danger"})
    @Html.HiddenFor(m => m.App.Id)

    <fieldset>
        <legend>Constraints</legend>
        @Html.EditorFor(m => m.Constraints.MaxInitialReleaseDateOfMinorVersion, "TextBox")
        @Html.EditorFor(m => m.Constraints.MaxStartups, "DropDownListVmInt")
        @Html.EditorFor(m => m.Constraints.MaxTimeFromFirstStartup, "DropDownListVmTimeSpan")
        @Html.EditorFor(m => m.Constraints.MaxTimeRunningApp, "DropDownListVmTimeSpan")
        @Html.EditorFor(m => m.Constraints.MaxVersion, "TextBox")
        @Html.EditorFor(m => m.Constraints.ValidTo, "TextBox")
    </fieldset>

// ...
}

// ConstraintsVm (Constraints property in CreateEditVm)
public class ConstraintsVm
{
    [Display(Name = "Time Limit from First Startup",
    Description = "Stops working after a given time after the first startup, regardless of how much it has been run after that.")]
    public DropDownListVm<TimeSpan> MaxTimeFromFirstStartup { get; set; }
    
    // ...
}

// DropDownListVmTimeSpan.cshtml
@model simplicense.ViewModels.Shared.DropDownListVm<TimeSpan>
<div class="form-group">
    @Html.LabelFor(x => x, new {@class = "col-md-3 control-label"})

    <div class="col-md-9">
        @Html.DropDownListFor(x => x.Value, Model.Values, new { @class = "form-control", title = ViewData.ModelMetadata.Description })
        <span class="help-block">@ViewData.ModelMetadata.Description</span>
        @Html.ValidationMessageFor(x => x, "", new {@class = "text-danger"})
    </div>
</div>

// TextBox.cshtml
@model Object
<div class="form-group">
    @Html.LabelFor(x => x, new {@class = "col-md-3 control-label"})
    <div class="col-md-9">
        @Html.TextBoxFor(x => x, new {@class = "form-control", title = ViewData.ModelMetadata.Description, placeholder = ViewData.ModelMetadata.Watermark})
        <span class="help-block">@ViewData.ModelMetadata.Description</span>
        @Html.ValidationMessageFor(x => x, "", new {@class = "text-danger"})
    </div>
</div>

// CheckBox.cshtml
@model bool
<div class="form-group">
    @Html.LabelFor(x => x, new {@class = "col-md-3 control-label"})
    <div class="col-md-9">
        @Html.CheckBoxFor(x => x, new { title = ViewData.ModelMetadata.Description })
        <span class="help-block">@ViewData.ModelMetadata.Description</span>
        @Html.ValidationMessageFor(x => x, "", new {@class = "text-danger"})
    </div>
</div>

// ControlModelBinder
using System;
using System.Web.Mvc;
using simplicense.ViewModels.Shared;

namespace simplicense.ViewModels.ModelBinders
{
    /// <remarks>Based on: http://stackoverflow.com/a/6333898/134761 </remarks>
    public class ControlModelBinder : DefaultModelBinder
    {
        protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext,
            Type modelType)
        {
            ValueProviderResult type = bindingContext.ValueProvider.GetValue(bindingContext.ModelName + ".Type");
            object model = null;
            switch (type.AttemptedValue)
            {
                case "textbox":
                {
                    model = new TextBoxVm<string>();
                    break;
                }
                case "checkbox":
                {
                    model = new CheckBoxVm();
                    break;
                }
                case "ddl":
                {
                    model = new DropDownListVm<string>();
                    break;
                }
                default:
                {
                    throw new NotImplementedException();
                }
            }
            ;

            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model,
                model.GetType());
            return model;
        }
    }
}

// View models
    public class DropDownListVm<TValue> : TextBoxVm<TValue>
    {
        public DropDownListVm()
        {
        }

        public DropDownListVm(SelectList<TValue> values)
        {
            Values = values;
            Value = values.SelectedValue;
        }

        public DropDownListVm(string label, string name, TValue value, SelectList values) : base(label, name, value)
        {
            Values = values;
        }

        public override string Type
        {
            get { return "ddl"; }
        }

        public SelectList Values { get; set; }
    }
    
    public class SelectList<TValue> : SelectList
    {
        public SelectList(IEnumerable<SelectItem<TValue>> items, TValue selectedValue)
            : base(items, "Value", "Text", selectedValue)
        {
        }

        [UsedImplicitly]
        public SelectList() : base(new List<TValue>())
        {
        }

        public new TValue SelectedValue
        {
            get { return (TValue) base.SelectedValue; }
        }
    }    
    
    public class SelectItem<TValue>
    {
        [UsedImplicitly]
        public SelectItem()
        {
        }

        public SelectItem(TValue value, string text)
        {
            Value = value;
            Text = text;
        }

        [UsedImplicitly]
        public TValue Value { get; set; }

        [UsedImplicitly]
        public string Text { get; set; }
    }