I'd like to alter ChildContent my component receives from the parent like this:
<Markdown>
# Title
Some _Content_
</Markdown>
To interpret this content I would need to do something like Markdown.ToHTML(#ChildContent).
But as ChildContent is not a string, I need some means to access the ChildContent and retrieve it as string. Is this possible and how can it be done? Any other idea to solve this?
This isn't impossible but it's not a great way to go.
In order to take a render fragment and produce HTML, it needs to be run through a renderer. This isn't a particularly simple thing to achieve. If you want to see an example you can look at the Test Renderer produced by Steve Sanderson for his unit testing prototype.
You could have a go at creating your own renderer but I would suggesting considering a different approach.
Most probably you have already found a solution, but take a look at the code snippet bellow (.NET 5.0):
var builder = new RenderTreeBuilder();
builder.AddContent(0, this.ChildContent);
var frame = builder.GetFrames().Array.FirstOrDefault(x => new[]
{
RenderTreeFrameType.Text,
RenderTreeFrameType.Markup
}.Any(t => x.FrameType == t));
var value = frame?.MarkupContent;
Adding content to builder adds two frames, a region one and a text/markup one, depending on whether ChildContent contains plain text of HTML. Instead of guessing however, it is safer to use FirstOrDefault.
NB: This is kind of a hack and is not guaranteed that would work in future version of Blazor. I haven't used it with Blazor 6.0 or 7.0 (in preview, yet to be released) but I am able to retrieve the content of, pardon me, ChildContent.
Related
I am currently trying to achieve something I think is quite simple:
Changing a background colour based on the role of the logged-in user.
I've got an if/if else setup in the SCSS already, but currently it's just using a hardcoded string.
I also know how to get the string value of the current user's role...
I do not know how to use C# things in SCSS though. When I discovered that '#{}' is used for implementing if/else etc, I naturally tried "#inject" and "#using"... but that didn't work, sadly.
How do I use C# code in SASS?
Generally this is done with a separate class on either the html or body elements. You can do this easily with Razor.
<html class="loggedin">
Then you just define custom overrides based on the selector.
html.loggedin
{
// do your custom stuff in this block.
}
I am new to C# and am trying to use SpecFlow as I used to use Gherkin by giving a unique name to an item and then passing in the name in the Step Definition. My question is about how to add in the identifier when I create an object so I can call the object without having to pass in the actual name of the object every time that I create a step.
So, for instance the code would look something like this:
[When(#"I click the (.*) button")]
public void ClickTheButton(string ButtonName)
{
driver.Click(ButtonName)
//ButtonName would be a string that would call to the ID for the ADD button
}
I want to be able to put in something like "Add" (so the line would read "When I click the ADD button") and then have the code search for the "ADD" identifier.
I know that this is possible in Ruby/Cucumber by using a DOM and then passing in XML with gherkin names. In Ruby/Cucumber the object would look something like this:
<button gherkin_name="ADD" key="id" value="add_button_12685"/>
However, I am finding absolutely no way of doing that in C# with SpecFlow and this is something that I really need to be able to do.
Is there a way to do this at all? All I'm really trying to do is link a handle/parameter name that business users could actually use to a Page Object like you can in Ruby/Cucumber without making the user know the code in the background. And, incidentally, the names of the objects are almost exactly like the gherkin line that I added in, thus they are very weird to have a user write. This is the reason that I'd like to have just an identifier for the user.
Thanks in advance for your help.
EDIT: I realise now I was not clear enough in my original post so perhaps some background will help. I am using Selenium-Webdriver to test a website that has hundreds of items on it. Writing a different step for every single item on every single page would be exceedingly tedious and time consuming. Because there are many of the exact same items with the exact same characteristics (for instance there are something like 50 buttons that all behave similarly on a single page and the site is dozens of pages) on the pages, writing a single method for testing them seems the most logical idea. Identifying these items with an identifier that the business could use would cut down on bulk inside of the Steps, the number of steps written, and the likelihood that the business users would feel comfortable using the code which is the end goal.
You can do what you want if you are using the PageObject pattern and have a property Buttons (probably on a base PageObject class) which exposes the available buttons as a collection (which can be done via reflection) and then you can just do something like:
[When(#"I click the (.*) button")]
public void ClickTheButton(string ButtonName)
{
myPage.Buttons.First(button=>button.Name==ButtonName).Click;
}
but I would take what AutomatedChaos said into consideration and not use this in a step in the gerkin but just have this as a helper method something like this
[When(#"I add a widget")]
public void AddAWidget(string ButtonName)
{
ClickTheButton("Add")
}
private void ClickTheButton(string ButtonName)
{
myPage.Buttons.First(button=>button.Name==ButtonName).Click;
}
your Buttons property doesn't have to be done with reflection, the simplest implementation is something like this:
public IEnumerable<IWebElement> Buttons
{
yield return AddButton;
yield return RemoveButton;
yield return SomeOtherButton;
//etc etc
}
but using reflection will mean that as you add buttons to the page object you don't need to remember to add them to this method, they will be found automatically.
SpecFlow is only the BDD framework. It will not drive browsers itself, you need to install additional packages that drives the browser.
With C#, you have a few options:
Selenium, the best known and works with the Page Object you are accustomed with.
Fluent Automation, an upcoming library that works as a wrapper on top of Selenium, and makes the interfacing easier (more natural language)
CodedUI, Microsofts web and UI test solution that comes natively with Visual Studio Test edition.
On a personal note, I consider Selenium (with or without Fluent Automation) the best fitted to work with SpecFlow (comparisson)
If you want to install Selenium or other packages, you can install the NuGet package manager to easily search, install and update packages for you.
Lastly, have you considered to use more domain specific Gherkin phrases like When I add a Wabberjock instead of When I press the Add button? This is where the power of BDD lies: Exposing the intention while hiding the implementation details.
Is there a way to expose Razor syntax and (custom) helpers to people , but say ... not allow them to create code blocks or , to only limit them in the usage of the helpers and to not give them the power to execute pure C# code in the views ?
Any ideas and pointers to similar solutions are welcome !
update:// I would like to give the users the power to write their own HTML and access only to a list of html helpers. Mostly the default ones and the ones i create.
For example i do not want them to be able to execute code within #{ //code } blocks and
Also no using and #model ( not sure about this one)
only have access to #Html.* #if else for foreach
or better yet , give them access only to specific namespaces (this just a thought tho)
update://
After some testing , i found out that RazorEngine does as close as to what i'm trying to do : run the views in isolated environment and add access to specific namespaces.
I would not recommend you doing that. There simply is not an easy and reliable way to give them this ability without compromising the security of your site. If you trust your users then you could do it. If you don't then a templating engine such as DotLiquid is something far more appropriate for this purpose.
There is a project called RazorEngine, built upon Microsoft's Razor, that allows you to parse that syntax without being in the context of returning an MVC view. Here's how it's used:
string template = "Hello #Model.Name! Welcome to Razor!";
string result = Razor.Parse(template, new { Name = "World" });
You can also specify a customized template base, which should allow you to define only the Html Helpers you want to expose to your users:
Razor.SetTemplateBase(typeof(HtmlTemplateBase<>));
string template =
#"<html>
<head>
<title>Hello #Model.Name</title>
</head>
<body>
Email: #Html.TextBoxFor(m => m.Email)
</body>
</html>";
var model = new PageModel { Name = "World", Email = "someone#somewhere.com" };
string result = Razor.Parse(template, model);
you may try to change razor view engine and related classes to check for disallowed situations.
When source is generated (view engine generates a source file to compile ), you have to check it manually (by parsing c# or vb.net code). It is possible, but not feasible (really).
Even if you have managed to parse and check code, you have to identify your code (which is allowed) and customer code (which has restrictions).
At the end you have to accept the fact you can not really disallow anything other than using another template engine.
because
Your customers will find a way to make their views look like yours.
You cannot limit most basic required features like var r = new Random();
You cannot estimate what most basic requirements are
you cannot say No to your customers when they need to use their custom libraries
By the way, you may try another thing. Write a virtual path provider, and convert customer templates written in AviatrixTemplate when requested by runtime. By using this route, you still use razor engine, loose only a slight time when converting (it is one time only). But your AviatrixTemplate won't be hilighted, and you still need to check for disallowed code.
PS: a basic loop may give your users more then you want. for example following code allows creation of a class and call it for one time. they may use fully qualified class name or may use Activator.CreateInstance.
#for (var r = new Random(); r != null; r = null)
{
#r.NextDouble()
}
just do not bother.
I have never done this before, but it sounds like you want to give users the ability to write code and have it compiled for use, yes?
If so, you may want to look into the CSharpCodeProvider class, the RazorTemplateEngine class and the System.CodeCom.Compiler namespace.
Have a look here for some information on those classes:
CSharpCodeProvider: http://support.microsoft.com/kb/304655
RazorTemplateEngine: http://msdn.microsoft.com/en-us/library/system.web.razor.razortemplateengine(v=vs.111).aspx
Whilst looking at a theme I downloaded from the Orchard CMS gallery, I noticed that a Layout.cshtml file had this block of code at the top of the file:
#functions {
// To support the layout classifaction below. Implementing as a razor function because we can, could otherwise be a Func<string[], string, string> in the code block following.
string CalcuClassify(string[] zoneNames, string classNamePrefix)
{
var zoneCounter = 0;
var zoneNumsFilled = string.Join("", zoneNames.Select(zoneName => { ++zoneCounter; return Model[zoneName] != null ? zoneCounter.ToString() : ""; }).ToArray());
return HasText(zoneNumsFilled) ? classNamePrefix + zoneNumsFilled : "";
}
}
I know what the declared function does (calculates which zones are populated in order to return the width of each column), my question is- what is the correct use of the #function block, and when should I ever use it?
The #functions block lets you define utility functions directly in the view, rather than adding them as extensions to the #Html helper or letting the controller know about display properties. You'd want to use it when you can meet these conditions:
The functionality is tied closely to the view and is not generally useful elsewhere (such as "How wide do I make my columns").
The functionality is more than a simple if statement, and/or is used in multiple places in your view.
Everything that the function needs to determine it's logic already exists in the Model for the view.
If you fail the first one, add it as a #Html helper.
If you fail the second one, just inline it.
If you fail the third one, you should do the calculation in your controller and pass the result as part of the model.
Others have explained what #functions does so I won't rehash that. But I would like to add this:
If your view is typed to a viewmodel, I think a viable option would be to move this logic into the viewmodel to avoid cluttering your markup with too much code. Otherwise your views start to look more and more like classic ASP and I don't think anybody wants that.
I don't think there's anything wrong with using #functions or #helper in your view, but once you get beyond a couple of methods in your view, or even if the function is somewhat complicated, it might be worth refactoring to the viewmodel if at all possible. If it's code that can be reused, it may be a good idea to to pull it out into a helper class or an extension to the HtmlHelper class. One thing that is a bummer is realizing you just rewrote a piece of code that already existed because you didn't know it was hidden away in some arbitrary view.
From msdn blogs, #functions block is to let you wrap up reusable code, like the methods and properties
In this particular case, the people who have created the theme you are using probably were trying to keep it as a simple theme (only views, css and images).
If you need to write some code for a theme for Orchard, you have to turn to a module (as stated here: http://docs.orchardproject.net/Documentation/Anatomy-of-a-theme) unless you write this code in the view.
I am not sure it is worth the time to switch from a theme to a module only to get the size of a column.
Basically I'm trying to implement some sort of poor man's Aspect Oriented Programming in C#. I had thought about using a ContextAttribute but they seem only be be bound at the class level. Is there any way that I can put an attribute in such that it will receive the same parameters as the method which it annotates or some way to access the context in which it fired?
I have this code
public void AddUser(User user)
{
var errors = DataAnnotationsValidationRunner.GetErrors(user);
if (errors.Any())
throw new RulesException(errors);
users.Add(user);
}
from which I would like to extract the first 3 lines so I had something like
[Validated]
public void AddUser(User user)
{
users.Add(user);
}
I think you are missing a third component. Most AOP implementations (e.g. Aspect#) rely on a proxy or interceptor to actually execute the code. In your scenario, you lack whichever component needed to 1) know the attribute exists on the method, and 2) trigger the mechanism (or become it) needed to execute the code within the attribute.
Fortunately, there are already many (fairly) simple solutions available in open source. The simplest option I can think of would be to use a compile-time weaver like PostSharp. Grab a copy of that, and in the samples you'll find several examples of exactly what you are trying to do (you'd be interested in the OnMethodInvocationAspect).
The end result is that your code looks exactly like it does in the sample you provided, yet it's also running the code you wish.
Don't know exactly how your solution should look like, but in C# attributes do not execute code as long as you don't request them (as far as I know). And if you query for the attribute, you also have the context. So there is something wrong with your strategy in my opinion.