Adds Knockout 3 bindings for rendering ASP.Net MVC input and validation markup for indexed primitive and complex types.

knockout-3.0.0.aspnet-bindings.js

// Assigns an ASP.Net MVC-style name attribute to a form field that is part of a list.
// Used inside a foreach: binding.
// Example for an indexed primitive type (string, int, etc.) :
// <div data-bind="foreach: Items">
// <input type="text" data-bind="value: SomeValue, aspnetIndexedName: 'Items'" />
// </div>
//
// The above will name the input fields "Items[0]", "Items[1]", etc.  For a complex type,
// a property can be specified in addition to the name:
// <div data-bind="foreach: Items">
// <input type="text" data-bind="value: FirstName, aspnetIndexedName: { name: 'Items', property: 'FirstName' }" />
// </div>
// or using a shorthand name.property form:
// <input type="text" data-bind="value: FirstName, aspnetIndexedName: 'Items.FirstName' }" />
//
// The above will name the input fields "Items[0].FirstName", "Items[1].FirstName", etc.
//
// The numeric index value defaults to the $index property of the binding context, but can be specified
// in the parameters:
// <div data-bind="foreach: Items">
// <input type="text" data-bind="value: FirstName, aspnetIndexedName: { name: 'Items', property: 'FirstName', index: Line }" />
// </div>
//
// For this to work properly with the ASP.Net MVC model binder, the index values must start at 0 and increase by 1; 
// the sequence cannot omit any values.
//
// To render validation errors, the ASP.Net MVC model state must be available through the viewmodel. One way to
// do this is:
// function MyViewModel {
//   var self = this;
//   ...
//   // Serialize the model state to capture the validation messages.
//   self.modelState = @Html.Raw(Newtonsoft.Json.JsonConvert.SerializeObject(ViewData.ModelState));
// }
;(function($) {
ko.bindingHandlers.aspnetIndexedName = {
	update: function (element, valueAccessor, allBindings, viewModel, bindingContext) {

		var name, property, index;
		var bindings = allBindings().aspnetIndexedName;

		// If just a string, parse it as "name.property".  For primitive values, property is empty.
		if (typeof bindings === "string") {
			var parts = bindings.split(".");
			name = parts[0];
			property = parts[1];
			index = bindingContext.$index();
		}
		else {
			name = bindings.name;
			property = bindings.property;
			index = bindings.index || bindingContext.$index();
		}

		var fullname = name + '[' + index + ']';
		if (property)
			fullname = fullname + '.' + property;

		$(element).attr({ name: fullname, id: fullname });


		// Is there a modelstate error?
		var modelStateProperty = bindings.modelState || 'modelState';
		var modelState = bindingContext.$root[modelStateProperty];
		if (modelState && modelState[fullname] && modelState[fullname].Errors.length) {
			$(element).addClass("input-validation-error");
		}

	}
}

// Populates an ASP.Net MVC validation control that is rendered within a foreach: binding.  The
// data-valmsg-for attribute is given the name of the input control, and the validation
// message is inserted.
// The validation messages must be serialized into the viewmodel.
//
// Example markup:
// <div data-bind="foreach: Items">
//   <input type="text" data-bind="value: FirstName, aspnetIndexedName: 'Items.FirstName' }" />
//   <span class="control-label" data-bind="aspnetIndexedValidation: 'Items.FirstName'}" />
// </div>
//
// Example view model:
// function MyViewModel {
//   var self = this;
//   ...
//   // Serialize the model state to capture the validation messages.
//   self.modelState = @Html.Raw(Newtonsoft.Json.JsonConvert.SerializeObject(ViewData.ModelState));
// }
ko.bindingHandlers.aspnetIndexedValidation = {
	update: function (element, valueAccessor, allBindings, viewModel, bindingContext) {

		var name, index, property;

		var bindings = allBindings().aspnetIndexedValidation;

		// If parameters are just a string, it's the name
		if (typeof bindings === "string") {
			var parts = bindings.split(".");
			name = parts[0];
			property = parts[1];
			index = bindingContext.$index();
		}
		else {
			name = bindings.name;
			property = bindings.property;
			index = bindings.index || bindingContext.$index();
		}

		var fullname = name + '[' + index + ']';
		if (property)
			fullname = fullname + '.' + property;

		$elem = $(element);

		$elem.attr({ 'data-valmsg-for': fullname });
		$elem.attr({ 'data-valmsg-replace': true });

		var modelStateProperty = bindings.modelState || 'modelState';

		// Insert initial error message
		var modelState = bindingContext.$root[modelStateProperty];
		if (modelState && modelState[fullname] && modelState[fullname].Errors.length) {
			$elem.text(modelState[fullname].Errors[0].ErrorMessage);
			$elem.addClass("field-validation-error");
		}
		else {
			$elem.addClass("field-validation-valid")
		}
	},
};
})(jQuery);

Renamed file so it can be picked up with a ScriptBundle -{version}; added closure for jQuery.