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Improved documentary #11

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Dec 12, 2014
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Improved documentary #11

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7aec2d1
Added syntax highlighting to intro.md
keichinger Dec 11, 2014
e509939
Updated intro.md
keichinger Dec 12, 2014
a5d56fd
Splitted first block into a new "documentary" section. Added "buildin…
keichinger Dec 12, 2014
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191 changes: 107 additions & 84 deletions Docs/intro.md
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,8 @@ So I began to think: what if we were to start anew with modern C# features such
Generics, Observables, async, etc etc. The result of that thought is Perspex
(https://github.com/grokys/Perspex).

**DISCLAIMER**: This is really early development pre-alpha-alpha stuff. Everything is subject to
##### DISCLAIMER
This is really **early development pre-alpha-alpha** stuff. Everything is subject to
change, I'm not even sure if the performance characteristics of Rx make Observables suitable for
binding throughout a framework. *I'm writing this only to see if the idea of exploring these ideas
appeals to anyone else.*
Expand All @@ -36,103 +37,117 @@ Attached Properties. So the challenge became to improve it.

Delaring a DP in WPF looks something like this:

public static readonly DependencyProperty PropertyDeclaration =
DependencyProperty.Register(
"PropertyName",
typeof(PropertyType),
typeof(OwnerClass),
new FrameworkPropertyMetadata(
default(PropertyType),
FrameworkPropertyMetadataOptions.Inherits));

public PropertyType PropertyName
{
get { return (PropertyType)this.GetValue(PropertyDeclaration); }
set { this.SetValue(PropertyDeclaration, value); }
}
```csharp
public static readonly DependencyProperty PropertyDeclaration =
DependencyProperty.Register(
"PropertyName",
typeof(PropertyType),
typeof(OwnerClass),
new FrameworkPropertyMetadata(
default(PropertyType),
FrameworkPropertyMetadataOptions.Inherits));

public PropertyType PropertyName
{
get { return (PropertyType)this.GetValue(PropertyDeclaration); }
set { this.SetValue(PropertyDeclaration, value); }
}
```

Eww! All that just to declare a single property. There's **A LOT** of boilerplate there. With
generics and default parameters we can at least make it look a bit nicer:

public static readonly PerspexProperty<PropertyType> PropertyDeclaration =
PerspexProperty.Register<OwnerClass, PropertyType>("PropertyName", inherits: true);
```csharp
public static readonly PerspexProperty<PropertyType> PropertyDeclaration =
PerspexProperty.Register<OwnerClass, PropertyType>("PropertyName", inherits: true);

public PropertyType PropertyName
{
get { return this.GetValue(PropertyDeclaration); }
set { this.SetValue(PropertyDeclaration, value); }
}
public PropertyType PropertyName
{
get { return this.GetValue(PropertyDeclaration); }
set { this.SetValue(PropertyDeclaration, value); }
}
```

What can we see here?

- PerpexProperties are typed, so no more having to cast in the getter.
- We pass the property type and owner class as a generic type to Register() so we don't have to
write typeof() twice.
- We used default parameter values in Rigister() so that defaults don't have to be restated.
- We pass the property type and owner class as a generic type to `Register()` so we don't have to
write `typeof()` twice.
- We used default parameter values in `Register()` so that defaults don't have to be restated.

*(ASIDE: maybe Roslyn will give us [var for fields](http://blogs.msdn.com/b/ericlippert/archive/2009/01/26/why-no-var-on-fields.aspx)...)? Lets hope...*

## Binding

Binding in Perspex uses Reactive Extensions' IObservable. To bind an IObservable to a property,
use the Bind method:
Binding in Perspex uses Reactive Extensions' [IObservable](http://msdn.microsoft.com/library/dd990377.aspx). To bind an IObservable to a property, use the `Bind()` method:

control.Bind(BorderProperty, someObject.SomeObservable());
```csharp
control.Bind(BorderProperty, someObject.SomeObservable());
```

Note that because PerspexProperty is typed, we can check that the observable is of the correct type.

To get the value of a property as an observable, call GetObservable():
To get the value of a property as an observable, call `GetObservable()`:

var observable = control.GetObservable(Control.FooProperty);
```csharp
var observable = control.GetObservable(Control.FooProperty);
```

## Attached Properties and Binding Pt 2

Attached properties are set just like in WPF, using SetValue. But what about the [] operator? C# 6
will allow us to use [] array subscripts in object initializers. So how does this look?
Attached properties are set just like in WPF, using `SetValue()`. But what about the `[]` operator, also called [index initializer](https://roslyn.codeplex.com/wikipage?title=Language%20Feature%20Status&referringTitle=Home) (see *C# feature descriptions*)? The upcoming version of C# will provide a new feature that allows us to use `[]` array subscripts in object initializers. An example on how to make use of it will look like this:

var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
}
```csharp
var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
}
```


Nice... Lets take this further:

var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!Property2] = something.SomeObservable,
}
```csharp
var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!Property2] = something.SomeObservable,
}
```

Yep, by putting a bang in front of the property name you can **bind** to a property (attached or
otherwise) from the object initializer.

Binding to a property on another control? Easy:

var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!Property2] = anotherControl[!Property1],
}
```csharp
var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!Property2] = anotherControl[!Property1],
}
```

Two way binding? Just add two bangs:

var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!!Property2] = anotherControl[!!Property1],
}
```csharp
var control = new Control
{
Property1 = "Foo",
[Attached.Property] = "Bar",
[!!Property2] = anotherControl[!!Property1],
}
```

## Visual and Logical trees

Perspex uses the same visual/logical tree separation that is used by WPF (and to some extent HTML
is moving in this direction with the Shadow DOM). The manner of accessing the two trees is slightly
different however. Rather than using Visual/LogicalTreeHelper you can cast any control to an
IVisual or ILogical to reveal the tree operations. There's also the VisualExtensions class which
`IVisual` or `ILogical` to reveal the tree operations. There's also the VisualExtensions class which
provides some useful extension methods such as `GetVisualAncestor<T>(this IVisual visual)` or
`GetVisualAt(this IVisual visual, Point p)`.

Expand All @@ -144,46 +159,54 @@ property, which is determined by...
Styles in Perspex diverge from styles in WPF quite a lot, and move towards a more CSS-like system.
It's probably easiest to show in an example. Here is the default style for the CheckBox control:

new Style(x => x.OfType<CheckBox>())
{
Setters = new[]
{
new Setter(Button.TemplateProperty, ControlTemplate.Create<CheckBox>(this.Template)),
},
},
new Style(x => x.OfType<CheckBox>().Template().Id("checkMark"))
{
Setters = new[]
{
new Setter(Shape.IsVisibleProperty, false),
},
},
new Style(x => x.OfType<CheckBox>().Class(":checked").Template().Id("checkMark"))
{
Setters = new[]
{
new Setter(Shape.IsVisibleProperty, true),
},
},
```csharp
new Style(x => x.OfType<CheckBox>())
{
Setters = new[]
{
new Setter(Button.TemplateProperty, ControlTemplate.Create<CheckBox>(this.Template))
}
};

new Style(x => x.OfType<CheckBox>().Template().Id("checkMark"))
{
Setters = new[]
{
new Setter(Shape.IsVisibleProperty, false)
}
};

new Style(x => x.OfType<CheckBox>().Class(":checked").Template().Id("checkMark"))
{
Setters = new[]
{
new Setter(Shape.IsVisibleProperty, true)
}
};
```

Let's see what's happening here:

new Style(x => x.OfType<CheckBox>())
```csharp
new Style(x => x.OfType<CheckBox>())
```

The constructor for the Style class defines the selector. Here we're saying "*this style applies to
all controls in the the visual tree of type CheckBox*". A more complex selector:

new Style(x => x.OfType<CheckBox>().Class(":checked").Template().Id("checkMark"))
```csharp
new Style(x => x.OfType<CheckBox>().Class(":checked").Template().Id("checkMark"))
```

This selector matches "*all controls with Id == "checkMark" in the template of a CheckBox with the
class ':checked'"*. Each control has an Id property, and Ids in templates are considered to be in a
class `:checked`"*. Each control has an Id property, and Ids in templates are considered to be in a
separate namespace.

Inside the Style class we then have a collection of setters similar to WPF.

This system means that there's no more need for WPF's Triggers - the styling works with classes
(which are arbitrary strings) similar to CSS. Similar to CSS, classes with a leading ":" are set
by the control itself in response to events like mouseover and click.
(which are arbitrary strings) similar to CSS. Similar to CSS, classes with a leading `:` are set
by the control itself in response to events like `mouseover` and `click`.

Similar to WPF, styles can be defined on each control, with a global application style collection
at the root. This means that different subsections of the visual tree can have a completely
Expand All @@ -192,11 +215,11 @@ different look-and-feel.
## XAML

As you can see, all of the examples here are defined in code - but a XAML implementation is being
worked on (https://github.com/SuperJMN/Perspex/tree/xamlreader)
worked on. The current progress can be reviewed at https://github.com/SuperJMN/Perspex/tree/fuent-api.

## That's all for now

There's a lot more to see, and even more to do, so if you want to have a play you can get the code
here: [https://github.com/grokys/Perspex](https://github.com/grokys/Perspex)

Feedback welcome!
Feedback is always welcome!
14 changes: 11 additions & 3 deletions readme.md
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Expand Up @@ -19,11 +19,19 @@ generics.
So I began to think: what if we were to start anew with modern C# features such as *(gasp)*
Generics, Observables, async, etc etc. The result of that thought is Perspex.

**DISCLAIMER**: This is really early development pre-alpha-alpha stuff. Everything is subject to
##### DISCLAIMER
This is really early development pre-alpha-alpha stuff. Everything is subject to
change, I'm not even sure if the performance characteristics of Rx make Observables suitable for
binding throughout a framework. *I'm writing this only to see if the idea of exploring these ideas
appeals to anyone else.*

[Take a look at the introduction document here.](Docs/intro.md)
## Documentary
Like mentioned above this is really an early version of Perplex and we're working hard on improving the code base and the documentary at the same time. Please feel free to have a look at our [introduction document](Docs/intro.md) to get things started real quick. Contributions are always welcome!

**NOTE**: This uses proposed C#6 features so you'll have to install a Roslyn preview. [If you're using VS2013, try here.]( https://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=52793)
## Building and Using
In order to build and use Perpex you need a compiler that supports the upcoming C# 6 features.

- **Visual Studio 2015 Preview**: The recommended way to compile C# 6 code is to use the new Visual Studio 2015 Preview version, which Microsoft has released later this year. It comes with the new Roslyn compiler and features like the new upcoming JIT (RyuJIT) and other improvements like extensible code analysis right out of the box. It can be downloaded [here](http://www.visualstudio.com/en-us/downloads/visual-studio-2015-downloads-vs)

- **Visual Studio 2013**: With the introductory of the new Roslyn compiler platform earlier this year Microsoft has released an *April End User Preview* which is a small extension that brings supports to Visual Studio 2013.<br/>
**NOTE**: This extension is **out of date** and will **no longer be updated**, according to the [Roslyn CodePlex](https://roslyn.codeplex.com/) main page. However, if you don't want to use a Preview IDE feel free to download the extension [over here](https://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=52793). It must be noted that it is not guaranteed that future versions of Perplex will compile and run when using this extension.