I have a TextBlock and to show translated text I use
x:Uid="/FileResourceName/txtControldName" Name="txtControlName"
(in resource file I write: txtControldName.Text = "some text") it works fine. But I would like to hide or show it depend on codebehind object and for that I use
Visibility="{Binding Path = IsMyControlVisible}"
(in that case for text I have to assign some text directly in control like Text="some text"). If I use one of this two properties everything works fine but simultaneously these two properties do not work. Is there any way to do the same?
If I use one of this two properties everything works fine but simultaneously these two properties do not work. Is there any way to do the same?
It's not a normal behavior. There is no conflict between binding to Visibility property and setting text in resource file. Have you set DataContext for your Binding?
Please see the following code sample, it worked well.
<Grid>
<TextBlock x:Uid="txtControldName" Visibility="{Binding IsMyControlVisible}"></TextBlock>
<Button Content="test" Click="Button_Click"></Button>
</Grid>
public sealed partial class MainPage : Page,INotifyPropertyChanged
{
private Visibility _IsMyControlVisible;
public Visibility IsMyControlVisible
{
get { return _IsMyControlVisible; }
set
{
_IsMyControlVisible = value;
RaisePropertyChange("IsMyControlVisible");
}
}
public MainPage()
{
this.InitializeComponent();
this.DataContext = this;
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChange(String PropertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,new PropertyChangedEventArgs(PropertyName));
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
IsMyControlVisible = IsMyControlVisible == Visibility.Collapsed ? Visibility.Visible : Visibility.Collapsed;
}
}
Please note that you need to implement the INotifyPropertyChanged interface, when the property value is change, it will notify the UI.
Related
How to present a string, number or a also view model with binding and DataTemplate?
I am looking for a MAUI replacement for the WPF ContentControl.
The ContentView has a Content property but this is from type View.
The ContentPresenter has a Content property but this is also from type View. <Ignorable>WTF, Why this is not named ViewPresenter when it can only present a View??? Someoteimes MAUI is weird.</Ignorable>
How to present any content with defining DataTemplates for each data type?
class PropertyViewModel {
public string Name {get;set;}
public object Value {get;set;}
}
<Page.Resources>
<DataTemplate DataType="System.String">
<Entry Text="{Binding}/>
</DataTemplate>
<DataTemplate DataType="System.Int32">
<NumberPicker Value="{Binding}/>
</DataTemplate>
.. more templates, eg. DatePicker for System.DateOnly
</Page.Resources>
<DockLayout>
<Label Text="{Binding Name}
<TemplatedContenView Content={Binding Value}/>
</DockPanel>
The TemplatedContenView or ContentControl (that does not exist in MAUI), can use different templates for different types of Value. In WPF the ContentControl uses ContentTemplate, ContentTemplateSelector or if none specified it looked into the resources to find the template.
<Ignorable>I often have the feeling with MAUI that I have to constantly reinvent things that are standard in WPF. Yes I know MAUI is not WPF, but there should still be at least similar concepts. The switch from WinForms to WPF was much easier and the differences were considerably greater.</Ignorable>
Edit1: a more detailed example
I'm a WPF developer and recently I've started MAUI project. And It looks like you have to reinvent the wheel every time when you are going to write such a simple scenario as you mentioned :(. When you do it using WPF you even don't need to thought about that, it's too easy to implement, but when you use MAUI you should break your mind to do such minor things.
I also encountered the same issue and I didn't find a simple in-box solution. But I came up with the idea to create a control with some layout inside that has attached properties from BindableLayout
TemplatedContentPresenter.xaml.cs:
public partial class TemplatedContentPresenter : ContentView
{
public TemplatedContentPresenter()
{
InitializeComponent();
}
public static readonly BindableProperty DataTemplateSelectorProperty = BindableProperty.Create(nameof(DataTemplateSelector), typeof(DataTemplateSelector), typeof(TemplatedContentPresenter), null, propertyChanged: DataTemplateSelectorChanged);
public static readonly BindableProperty DataTemplateProperty = BindableProperty.Create(nameof(DataTemplate), typeof(DataTemplate), typeof(TemplatedContentPresenter), null, propertyChanged: DataTemplateChanged);
public static readonly BindableProperty DataProperty = BindableProperty.Create(nameof(Data), typeof(object), typeof(TemplatedContentPresenter), null, propertyChanged: DataChanged);
public DataTemplateSelector DataTemplateSelector
{
get =>(DataTemplateSelector)GetValue(DataTemplateSelectorProperty);
set => SetValue(DataTemplateSelectorProperty, value);
}
public DataTemplate DataTemplate
{
get => (DataTemplate)GetValue(DataTemplateProperty);
set => SetValue(DataTemplateProperty, value);
}
public object Data
{
get => GetValue(DataProperty);
set => SetValue(DataProperty, value);
}
private static void DataTemplateSelectorChanged(BindableObject bindable, object oldValue, object newValue)
{
if(bindable is TemplatedContentPresenter contentPresenter && newValue is DataTemplateSelector dataTemplateSelector)
{
BindableLayout.SetItemTemplateSelector(contentPresenter.HostGrid, dataTemplateSelector);
}
}
private static void DataTemplateChanged(BindableObject bindable, object oldValue, object newValue)
{
if (bindable is TemplatedContentPresenter contentPresenter && newValue is DataTemplate dataTemplate)
{
BindableLayout.SetItemTemplate(contentPresenter.HostGrid, dataTemplate);
}
}
private static void DataChanged(BindableObject bindable, object oldValue, object newValue)
{
if (bindable is TemplatedContentPresenter contentPresenter)
{
BindableLayout.SetItemsSource(contentPresenter.HostGrid, new object[] { newValue });
}
}
}
TemplatedContentPresenter.xaml:
<?xml version="1.0" encoding="utf-8" ?>
<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="MyApp.TemplatedContentPresenter">
<Grid x:Name="HostGrid" x:FieldModifier="private" />
</ContentView>
Usage:
<Frame WidthRequest="500" HeightRequest="500">
<controls:TemplatedContentPresenter
Data="{Binding}"
DataTemplateSelector="{StaticResource CardTemplateSelector}"/>
</Frame>
UPD:
While I was writing the answer I came up with another solution with a simple converter:
SingleObjectToArray.xaml
internal class SingleObjectToArray : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return new object[] { value };
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
Usage:
<Frame>
<Frame.Resources>
<converters:SingleObjectToArray x:Key="SingleObjectToArrayConverter"/>
</Frame.Resources>
<Grid BindableLayout.ItemsSource="{Binding Converter={StaticResource SingleObjectToArrayConverter}}"
BindableLayout.ItemTemplateSelector="{StaticResource CardTemplateSelector}" />
</Frame>
I try to set the values of a selectManyCheckbox to my testBean backing bean.
If I use a property of type List<String> instead of Attributed<List<String>> it works perfectly. It is the workaround I'm using currently.
But on my backing bean I have a generic object which contains the List.
The javax.el.BeanELResolver resolve this to an Object. Which is correct due to Type erasure.
I tried to implement a custom ElResolver. But I should know to which type to convert the object to. It isn't obviously always a List. I have the information in the xhtml pages. So I hoped I could pass some child element which would contain the information, but could not find a way to access the child element from the ElResolver.
A Custom converted does not work either as it converts selectItems, not the List.
Here is the simplest form
<h:form>
<p:selectManyCheckbox value="#{testBean.attributed.value}" >
<f:selectItems value="#{testBean.selection}" />
</p:selectManyCheckbox>
<p:commandButton action="#{testBean.execute}" value="do it" />
</h:form>
and the bean
private Attributed<List<String>> attributed = new Attributed<>();
public Map<String, String> getSelection() {
return ImmutableMap.<String, String> of("key1", "value1", "key2", "value2");
}
public static class Attributed<T> {
private T value;
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
}
}
public Attributed<List<String>> getAttributed() {
return attributed;
}
public void setAttributed(Attributed<List<String>> attributed) {
this.attributed = attributed;
}
So the question is:
Is there a way to set the value to testBean.attributed.value directly and with the correct type.
Is it possible by defining a custom ElResolver, or are there other way to do it?
The situation is that I have a ViewScoped page that uses ui:repeat for laying out some components. I also on this page have some h:commandLinks that have action method specified. The action method performs some conditional logic to determine what navigation outcome to return. Upon returning an outcome and including "faces-redirect=true" to perform a redirect, the current view's bean is reinstantiated before the redirect occurs.
Removing the ui:repeat causes the issue to stop, I know longer see the constructor of the bean being invoked. Also, I cannot use h:links in this case, because I want to be able to calculate the outcome at the moment the link is clicked.
Is this a known bug with ui:repeat? I have searched around and could not find why this is happening.
Here is some sample code that I can reproduce this with using Mojarra JSF 2.1.6:
example.xhtml
<h:form>
<h:outputText value="Bean property value: #{exampleBean.property}"/>
<ui:repeat value="#{exampleBean.list}" var="item">
<h:outputText value="#{item}"/>
</ui:repeat>
<br/><h:commandLink value="Action" action="#{exampleBean.someAction()}"/>
<br/><h:commandLink value="Action w/Redirect" action="#{exampleBean.someRedirectAction()}"/>
</h:form>
ExampleBean.java
#ManagedBean(name="exampleBean")
#ViewScoped
public class ExampleBean {
private String property;
private List<String> list;
public ExampleBean() {
System.err.println("Constructor invoked");
list = new ArrayList<String>();
list.add("list item 1");
list.add("list item 2");
}
public String getProperty() {
return property;
}
public void setProperty(String property) {
this.property = property;
}
public List<String> getList() {
return list;
}
public void setList(List<String> list) {
this.list = list;
}
public String someAction() {
System.err.println("someAction() invoked");
if (calculateSomeCondition()) {
return "otherView1";
} else {
return "otherView2";
}
}
public String someRedirectAction() {
System.err.println("someRedirectAction() invoked");
if (calculateSomeCondition()) {
return "otherView1?faces-redirect=true";
} else {
return "otherView2?faces-redirect=true";
}
}
private boolean calculateSomeCondition() {
// some logic to calc true/false
}
}
Note that otherView1.xhtml and otherView2.xhtml are simple files sitting in the same directory as example.xhtml.
The output seen in the log upon loading the page and clicking the "Action" link:
Constructor invoked
someAction() invoked
The output seen in the log upon loading the page and clicking the "Action w/Redirect" link:
Constructor invoked
someRedirectAction() invoked
Constructor invoked
In the past I've stuck common properties, such as the current user, onto ViewData/ViewBag in a global fashion by having all Controllers inherit from a common base controller.
This allowed my to use IoC on the base controller and not just reach out into global shared for such data.
I'm wondering if there is an alternate way of inserting this kind of code into the MVC pipeline?
The best way is using the ActionFilterAttribute. I'll show you how to use it in .Net Core and .Net Framework.
.Net Core 2.1 & 3.1
public class ViewBagActionFilter : ActionFilterAttribute
{
public ViewBagActionFilter(IOptions<Settings> settings){
//DI will inject what you need here
}
public override void OnResultExecuting(ResultExecutingContext context)
{
// for razor pages
if (context.Controller is PageModel)
{
var controller = context.Controller as PageModel;
controller.ViewData.Add("Avatar", $"~/avatar/empty.png");
// or
controller.ViewBag.Avatar = $"~/avatar/empty.png";
//also you have access to the httpcontext & route in controller.HttpContext & controller.RouteData
}
// for Razor Views
if (context.Controller is Controller)
{
var controller = context.Controller as Controller;
controller.ViewData.Add("Avatar", $"~/avatar/empty.png");
// or
controller.ViewBag.Avatar = $"~/avatar/empty.png";
//also you have access to the httpcontext & route in controller.HttpContext & controller.RouteData
}
base.OnResultExecuting(context);
}
}
Then you need to register this in your startup.cs.
.Net Core 3.1
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews(options => {
options.Filters.Add<Components.ViewBagActionFilter>();
});
}
.Net Core 2.1
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(options =>
{
options.Filters.Add<Configs.ViewBagActionFilter>();
});
}
Then you can use it in all views and pages
#ViewData["Avatar"]
#ViewBag.Avatar
.Net Framework (ASP.NET MVC .Net Framework)
public class UserProfilePictureActionFilter : ActionFilterAttribute
{
public override void OnResultExecuting(ResultExecutingContext filterContext)
{
filterContext.Controller.ViewBag.IsAuthenticated = MembershipService.IsAuthenticated;
filterContext.Controller.ViewBag.IsAdmin = MembershipService.IsAdmin;
var userProfile = MembershipService.GetCurrentUserProfile();
if (userProfile != null)
{
filterContext.Controller.ViewBag.Avatar = userProfile.Picture;
}
}
}
register your custom class in the global. asax (Application_Start)
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
GlobalFilters.Filters.Add(new UserProfilePictureActionFilter(), 0);
}
Then you can use it in all views
#ViewBag.IsAdmin
#ViewBag.IsAuthenticated
#ViewBag.Avatar
Also there is another way
Creating an extension method on HtmlHelper
[Extension()]
public string MyTest(System.Web.Mvc.HtmlHelper htmlHelper)
{
return "This is a test";
}
Then you can use it in all views
#Html.MyTest()
Since ViewBag properties are, by definition, tied to the view presentation and any light view logic that may be necessary, I'd create a base WebViewPage and set the properties on page initialization. It's very similar to the concept of a base controller for repeated logic and common functionality, but for your views:
public abstract class ApplicationViewPage<T> : WebViewPage<T>
{
protected override void InitializePage()
{
SetViewBagDefaultProperties();
base.InitializePage();
}
private void SetViewBagDefaultProperties()
{
ViewBag.GlobalProperty = "MyValue";
}
}
And then in \Views\Web.config, set the pageBaseType property:
<system.web.webPages.razor>
<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<pages pageBaseType="MyNamespace.ApplicationViewPage">
<namespaces>
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
</namespaces>
</pages>
</system.web.webPages.razor>
Un-tried by me, but you might look at registering your views and then setting the view data during the activation process.
Because views are registered on-the-fly, the registration syntax doesn't help you with connecting to the Activated event, so you'd need to set it up in a Module:
class SetViewBagItemsModule : Module
{
protected override void AttachToComponentRegistration(
IComponentRegistration registration,
IComponentRegistry registry)
{
if (typeof(WebViewPage).IsAssignableFrom(registration.Activator.LimitType))
{
registration.Activated += (s, e) => {
((WebViewPage)e.Instance).ViewBag.Global = "global";
};
}
}
}
This might be one of those "only tool's a hammer"-type suggestions from me; there may be simpler MVC-enabled ways to get at it.
Edit: Alternate, less code approach - just attach to the Controller
public class SetViewBagItemsModule: Module
{
protected override void AttachToComponentRegistration(IComponentRegistry cr,
IComponentRegistration reg)
{
Type limitType = reg.Activator.LimitType;
if (typeof(Controller).IsAssignableFrom(limitType))
{
registration.Activated += (s, e) =>
{
dynamic viewBag = ((Controller)e.Instance).ViewBag;
viewBag.Config = e.Context.Resolve<Config>();
viewBag.Identity = e.Context.Resolve<IIdentity>();
};
}
}
}
Edit 2: Another approach that works directly from the controller registration code:
builder.RegisterControllers(asm)
.OnActivated(e => {
dynamic viewBag = ((Controller)e.Instance).ViewBag;
viewBag.Config = e.Context.Resolve<Config>();
viewBag.Identity = e.Context.Resolve<IIdentity>();
});
Brandon's post is right on the money. As a matter of fact, I would take this a step further and say that you should just add your common objects as properties of the base WebViewPage so you don't have to cast items from the ViewBag in every single View. I do my CurrentUser setup this way.
You could use a custom ActionResult:
public class GlobalView : ActionResult
{
public override void ExecuteResult(ControllerContext context)
{
context.Controller.ViewData["Global"] = "global";
}
}
Or even a ActionFilter:
public class GlobalView : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
filterContext.Result = new ViewResult() {ViewData = new ViewDataDictionary()};
base.OnActionExecuting(filterContext);
}
}
Had an MVC 2 project open but both techniques still apply with minor changes.
You don't have to mess with actions or change the model, just use a base controller and cast the existing controller from the layout viewcontext.
Create a base controller with the desired common data (title/page/location etc) and action initialization...
public abstract class _BaseController:Controller {
public Int32 MyCommonValue { get; private set; }
protected override void OnActionExecuting(ActionExecutingContext filterContext) {
MyCommonValue = 12345;
base.OnActionExecuting(filterContext);
}
}
Make sure every controller uses the base controller...
public class UserController:_BaseController {...
Cast the existing base controller from the view context in your _Layout.cshml page...
#{
var myController = (_BaseController)ViewContext.Controller;
}
Now you can refer to values in your base controller from your layout page.
#myController.MyCommonValue
If you want compile time checking and intellisense for the properties in your views then the ViewBag isn't the way to go.
Consider a BaseViewModel class and have your other view models inherit from this class, eg:
Base ViewModel
public class BaseViewModel
{
public bool IsAdmin { get; set; }
public BaseViewModel(IUserService userService)
{
IsAdmin = userService.IsAdmin;
}
}
View specific ViewModel
public class WidgetViewModel : BaseViewModel
{
public string WidgetName { get; set;}
}
Now view code can access the property directly in the view
<p>Is Admin: #Model.IsAdmin</p>
I have found the following approach to be the most efficient and gives excellent control utilizing the _ViewStart.chtml file and conditional statements when necessary:
_ViewStart:
#{
Layout = "~/Views/Shared/_Layout.cshtml";
var CurrentView = ViewContext.Controller.ValueProvider.GetValue("controller").RawValue.ToString();
if (CurrentView == "ViewA" || CurrentView == "ViewB" || CurrentView == "ViewC")
{
PageData["Profile"] = db.GetUserAccessProfile();
}
}
ViewA:
#{
var UserProfile= PageData["Profile"] as List<string>;
}
Note:
PageData will work perfectly in Views; however, in the case of a
PartialView, it will need to be passed from the View to
the child Partial.
I implemented the ActionFilterAttribute solution from #Mohammad Karimi. It worked well as I had the same scenario as the OP. I needed to add data to every view. The action filter attribute was executed for every Razor page request, but it was also called for every web API controller request.
Razor Pages offers a page filter attribute to avoid unnecessary execution of the action filter when a web API controller request is made.
Razor Page filters IPageFilter and IAsyncPageFilter allow Razor Pages to run code before and after a Razor Page handler is run.
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Configuration;
namespace MyProject
{
// learn.microsoft.com/en-us/aspnet/core/razor-pages/filter?view=aspnetcore-6.0
// "The following code implements the synchronous IPageFilter"
// Enable the page filter using 'services.AddRazorPages().AddMvcOptions( ... )
// in the 'ConfigureServices()' startup method.
public class ViewDataPageFilter : IPageFilter
{
private readonly IConfiguration _config;
public ViewDataPageFilter(IConfiguration config)
{
_config = config;
}
// "Called after a handler method has been selected,
// but before model binding occurs."
public void OnPageHandlerSelected(PageHandlerSelectedContext context)
{
}
// "Called before the handler method executes,
// after model binding is complete."
public void OnPageHandlerExecuting(PageHandlerExecutingContext context)
{
PageModel page = context.HandlerInstance as PageModel;
if (page == null) { return; }
page.ViewData["cdn"] = _config["cdn:url"];
}
// "Called after the handler method executes,
// before the action result."
public void OnPageHandlerExecuted(PageHandlerExecutedContext context)
{
}
}
}
As per the sample in the filter methods for Razor Pages documentation, the page filter is enabled by:
public void ConfigureServices(IServiceCollection services)
{
services.AddRazorPages()
.AddMvcOptions(options =>
{
options.Filters.Add(new ViewDataPageFilter(Configuration));
});
}
Setup:
CustomViewEngine
CustomController Base
CustomViewPage Base (in this base, a new property is added "MyCustomProperty")
Problem:
When a view is strongly typed such as: <# Page Inherits="CustomViewPage<MyCustomObject" MyCustomProperty="Hello">, I get a compiler "Parser" error stating that MyCustomProperty is not a public property of System.Web.Mvc.ViewPage
I have done numerous trial and errors (see below) to see whats causing this error and have come to the following conclusions:
The error only occurs when I declare "MyCustomProperty" or any other property in the #Page directive of the view.
The error will always display "System.Web.Mvc.ViewPage" rather than the declared inherits=".." class.
Update: Looks like Technitium found another way to do this that looks much easier, at least on newer versions of ASP.NET MVC. (copied his comment below)
I'm not sure if this is new in ASP.NET MVC 3, but when I swapped the
Inherits attribute from referencing the generic in C# syntax to CLR
syntax, the standard ViewPageParserFilter parsed generics correctly --
no CustomViewTypeParserFilter required. Using Justin's examples, this
means swapping
<%# Page Language="C#" MyNewProperty="From #Page directive!"
Inherits="JG.ParserFilter.CustomViewPage<MvcApplication1.Models.FooModel>
to
<%# Page Language="C#" MyNewProperty="From #Page directive!"`
Inherits="JG.ParserFilter.CustomViewPage`1[MvcApplication1.Models.FooModel]>
Original answer below:
OK, I solved this. Was a fascinating exercise, and the solution is non-trivial but not too hard once you get it working the first time.
Here's the underlying issue: the ASP.NET page parser does not support generics as a page type.
The way ASP.NET MVC worked around this was by fooling the underlying page parser into thinking that the page is not generic. They did this by building a custom PageParserFilter and a custom FileLevelPageControlBuilder. The parser filter looks for a generic type, and if it finds one, swaps it out for the non-generic ViewPage type so that the ASP.NET parser doesn't choke. Then, much later in the page compilation lifecycle, their custom page builder class swaps the generic type back in.
This works because the generic ViewPage type derives from the non-generic ViewPage, and all the interesting properties that are set in a #Page directive exist on the (non-generic) base class. So what's really happening when properties are set in the #Page directive is that those property names are being validated against the non-generic ViewPage base class.
Anyway, this works great in most cases, but not in yours because they hardcode ViewPage as the non-generic base type in their page filter implementation and don't provide an easy way to change it. This is why you kept seeing ViewPage in your error message, since the error happens in between when ASP.NET swaps in the ViewPage placeholder and when it swaps back the generic ViewPage right before compilation.
The fix is to create your own version of the following:
page parser filter - this is almost an exact copy of ViewTypeParserFilter.cs in the MVC source, with the only difference being that it refers to your custom ViewPage and page builder types instead of MVC's
page builder - this is identical to ViewPageControlBuilder.cs in the MVC source, but it puts the class in your own namespace as opposed to theirs.
Derive your custom viewpage class directly from System.Web.Mvc.ViewPage (the non-generic version). Stick any custom properties on this new non-generic class.
derive a generic class from #3, copying the code from the ASP.NET MVC source's implementation of ViewPage.
repeat #2, #3, and #4 for user controls (#Control) if you also need custom properties on user control directives too.
Then you need to change the web.config in your views directory (not the main app's web.config) to use these new types instead of MVC's default ones.
I've enclosed some code samples illustrating how this works. Many thanks to Phil Haack's article to help me understand this, although I had to do a lot of poking around the MVC and ASP.NET source code too to really understand it.
First, I'll start with the web.config changes needed in your web.config:
<pages
validateRequest="false"
pageParserFilterType="JG.ParserFilter.CustomViewTypeParserFilter"
pageBaseType="JG.ParserFilter.CustomViewPage"
userControlBaseType="JG.ParserFilter.CustomViewUserControl">
Now, here's the page parser filter (#1 above):
namespace JG.ParserFilter {
using System;
using System.Collections;
using System.Web.UI;
using System.Web.Mvc;
internal class CustomViewTypeParserFilter : PageParserFilter
{
private string _viewBaseType;
private DirectiveType _directiveType = DirectiveType.Unknown;
private bool _viewTypeControlAdded;
public override void PreprocessDirective(string directiveName, IDictionary attributes) {
base.PreprocessDirective(directiveName, attributes);
string defaultBaseType = null;
// If we recognize the directive, keep track of what it was. If we don't recognize
// the directive then just stop.
switch (directiveName) {
case "page":
_directiveType = DirectiveType.Page;
defaultBaseType = typeof(JG.ParserFilter.CustomViewPage).FullName; // JG: inject custom types here
break;
case "control":
_directiveType = DirectiveType.UserControl;
defaultBaseType = typeof(JG.ParserFilter.CustomViewUserControl).FullName; // JG: inject custom types here
break;
case "master":
_directiveType = DirectiveType.Master;
defaultBaseType = typeof(System.Web.Mvc.ViewMasterPage).FullName;
break;
}
if (_directiveType == DirectiveType.Unknown) {
// If we're processing an unknown directive (e.g. a register directive), stop processing
return;
}
// Look for an inherit attribute
string inherits = (string)attributes["inherits"];
if (!String.IsNullOrEmpty(inherits)) {
// If it doesn't look like a generic type, don't do anything special,
// and let the parser do its normal processing
if (IsGenericTypeString(inherits)) {
// Remove the inherits attribute so the parser doesn't blow up
attributes["inherits"] = defaultBaseType;
// Remember the full type string so we can later give it to the ControlBuilder
_viewBaseType = inherits;
}
}
}
private static bool IsGenericTypeString(string typeName) {
// Detect C# and VB generic syntax
// REVIEW: what about other languages?
return typeName.IndexOfAny(new char[] { '<', '(' }) >= 0;
}
public override void ParseComplete(ControlBuilder rootBuilder) {
base.ParseComplete(rootBuilder);
// If it's our page ControlBuilder, give it the base type string
CustomViewPageControlBuilder pageBuilder = rootBuilder as JG.ParserFilter.CustomViewPageControlBuilder; // JG: inject custom types here
if (pageBuilder != null) {
pageBuilder.PageBaseType = _viewBaseType;
}
CustomViewUserControlControlBuilder userControlBuilder = rootBuilder as JG.ParserFilter.CustomViewUserControlControlBuilder; // JG: inject custom types here
if (userControlBuilder != null) {
userControlBuilder.UserControlBaseType = _viewBaseType;
}
}
public override bool ProcessCodeConstruct(CodeConstructType codeType, string code) {
if (codeType == CodeConstructType.ExpressionSnippet &&
!_viewTypeControlAdded &&
_viewBaseType != null &&
_directiveType == DirectiveType.Master) {
// If we're dealing with a master page that needs to have its base type set, do it here.
// It's done by adding the ViewType control, which has a builder that sets the base type.
// The code currently assumes that the file in question contains a code snippet, since
// that's the item we key off of in order to know when to add the ViewType control.
Hashtable attribs = new Hashtable();
attribs["typename"] = _viewBaseType;
AddControl(typeof(System.Web.Mvc.ViewType), attribs);
_viewTypeControlAdded = true;
}
return base.ProcessCodeConstruct(codeType, code);
}
// Everything else in this class is unrelated to our 'inherits' handling.
// Since PageParserFilter blocks everything by default, we need to unblock it
public override bool AllowCode {
get {
return true;
}
}
public override bool AllowBaseType(Type baseType) {
return true;
}
public override bool AllowControl(Type controlType, ControlBuilder builder) {
return true;
}
public override bool AllowVirtualReference(string referenceVirtualPath, VirtualReferenceType referenceType) {
return true;
}
public override bool AllowServerSideInclude(string includeVirtualPath) {
return true;
}
public override int NumberOfControlsAllowed {
get {
return -1;
}
}
public override int NumberOfDirectDependenciesAllowed {
get {
return -1;
}
}
public override int TotalNumberOfDependenciesAllowed {
get {
return -1;
}
}
private enum DirectiveType {
Unknown,
Page,
UserControl,
Master,
}
}
}
Here's the page builder class (#2 above):
namespace JG.ParserFilter {
using System.CodeDom;
using System.Web.UI;
internal sealed class CustomViewPageControlBuilder : FileLevelPageControlBuilder {
public string PageBaseType {
get;
set;
}
public override void ProcessGeneratedCode(
CodeCompileUnit codeCompileUnit,
CodeTypeDeclaration baseType,
CodeTypeDeclaration derivedType,
CodeMemberMethod buildMethod,
CodeMemberMethod dataBindingMethod) {
// If we find got a base class string, use it
if (PageBaseType != null) {
derivedType.BaseTypes[0] = new CodeTypeReference(PageBaseType);
}
}
}
}
And here's the custom view page classes: the non-generic base (#3 above) and the generic derived class (#4 above):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Diagnostics.CodeAnalysis;
using System.Web.Mvc;
namespace JG.ParserFilter
{
[FileLevelControlBuilder(typeof(JG.ParserFilter.CustomViewPageControlBuilder))]
public class CustomViewPage : System.Web.Mvc.ViewPage //, IAttributeAccessor
{
public string MyNewProperty { get; set; }
}
[FileLevelControlBuilder(typeof(JG.ParserFilter.CustomViewPageControlBuilder))]
public class CustomViewPage<TModel> : CustomViewPage
where TModel : class
{
// code copied from source of ViewPage<T>
private ViewDataDictionary<TModel> _viewData;
public new AjaxHelper<TModel> Ajax
{
get;
set;
}
public new HtmlHelper<TModel> Html
{
get;
set;
}
public new TModel Model
{
get
{
return ViewData.Model;
}
}
[SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public new ViewDataDictionary<TModel> ViewData
{
get
{
if (_viewData == null)
{
SetViewData(new ViewDataDictionary<TModel>());
}
return _viewData;
}
set
{
SetViewData(value);
}
}
public override void InitHelpers()
{
base.InitHelpers();
Ajax = new AjaxHelper<TModel>(ViewContext, this);
Html = new HtmlHelper<TModel>(ViewContext, this);
}
protected override void SetViewData(ViewDataDictionary viewData)
{
_viewData = new ViewDataDictionary<TModel>(viewData);
base.SetViewData(_viewData);
}
}
}
And here are the corresponding classes for user controls (#5 above) :
namespace JG.ParserFilter
{
using System.Diagnostics.CodeAnalysis;
using System.Web.Mvc;
using System.Web.UI;
[FileLevelControlBuilder(typeof(JG.ParserFilter.CustomViewUserControlControlBuilder))]
public class CustomViewUserControl : System.Web.Mvc.ViewUserControl
{
public string MyNewProperty { get; set; }
}
public class CustomViewUserControl<TModel> : CustomViewUserControl where TModel : class
{
private AjaxHelper<TModel> _ajaxHelper;
private HtmlHelper<TModel> _htmlHelper;
private ViewDataDictionary<TModel> _viewData;
public new AjaxHelper<TModel> Ajax {
get {
if (_ajaxHelper == null) {
_ajaxHelper = new AjaxHelper<TModel>(ViewContext, this);
}
return _ajaxHelper;
}
}
public new HtmlHelper<TModel> Html {
get {
if (_htmlHelper == null) {
_htmlHelper = new HtmlHelper<TModel>(ViewContext, this);
}
return _htmlHelper;
}
}
public new TModel Model {
get {
return ViewData.Model;
}
}
[SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public new ViewDataDictionary<TModel> ViewData {
get {
EnsureViewData();
return _viewData;
}
set {
SetViewData(value);
}
}
protected override void SetViewData(ViewDataDictionary viewData) {
_viewData = new ViewDataDictionary<TModel>(viewData);
base.SetViewData(_viewData);
}
}
}
namespace JG.ParserFilter {
using System.CodeDom;
using System.Web.UI;
internal sealed class CustomViewUserControlControlBuilder : FileLevelUserControlBuilder {
internal string UserControlBaseType {
get;
set;
}
public override void ProcessGeneratedCode(
CodeCompileUnit codeCompileUnit,
CodeTypeDeclaration baseType,
CodeTypeDeclaration derivedType,
CodeMemberMethod buildMethod,
CodeMemberMethod dataBindingMethod) {
// If we find got a base class string, use it
if (UserControlBaseType != null) {
derivedType.BaseTypes[0] = new CodeTypeReference(UserControlBaseType);
}
}
}
}
Finally, here's a sample View which shows this in action:
<%# Page Language="C#" MyNewProperty="From #Page directive!" Inherits="JG.ParserFilter.CustomViewPage<MvcApplication1.Models.FooModel>" %>
<%=Model.SomeString %>
<br /><br />this.MyNewPrroperty = <%=MyNewProperty%>
</asp:Content>