Grid improvements

[stevenbrix]

Specifying Grid/ColumnDefinitions in markup is tedious. Avalonia came up with a really nice syntax that lets you specify them like this:

<Grid ColumnDefintions = "Auto,*,*" RowDefinitions="Auto,*,*" >
   ...
</Grid>

Instead of the old syntax:

<Grid>
   <Grid.ColumnDefinitions>
     <ColumnDefintion Width="Auto"/>
     <ColumnDefintion Width="*"/>
     <ColumnDefintion Width="*"/>
   </Grid.ColumnDefinitions>
   <Grid.RowDefinitions>
     <RowDefinition Height="Auto"/>
     <RowDefinition Height="*"/>
     <RowDefinition Height="*"/>
   </Grid.RowDefinitions>
…
</Grid>

[Rand-Random]

Nice idea, just wanted to throw in that your issue title is very very generic.
Maybe consider rename it to actually contain the improvement your issue talks about.
Sorry, for being picky.

[dotMorten]

I agree, and I've seen this suggested several times before. It's really nothing more than adding a simple type converter here. I'd be more than happy to volunteer for providing this - however I assume there needs to be some sort of spec/language/API discussion first?

A few immediate issues I see though that will complicate "it's just a typeconverter" argument:

• Grid.RowDefinitions/ColumnDefinitions are read-only.
• RowDefinitionCollection/ColumnDefinitionCollection are not creatable publicly, and internally they are only creatable with a Grid parent parsed into the constructor.

[dotMorten]

Poking around in the reference source, looks like there's a lot more to it: There doesn't seem to be anything anywhere that can convert a string to a set of adds on an existing read-only collection. Rather than making the collection creatable and settable, which seems to introduce a lot of other issues, to solve this right, we might have to introduce an entirely new CollectionTypeConverter concept of sorts first (this would actually be useful for a lot of other scenarios too)

[Symbai]

I really like this idea, but would also heavily appreciate if this can be adopted to children as well in any kind. The less repetitive code the better.

For example instead of writing lots of repetitive code like this:

<Button Grid.Row="0" Grid.Column="0"/>
<Button Grid.Row="0" Grid.Column="1"/>
<Button Grid.Row="0" Grid.Column="2"/>
<Button Grid.Row="1" Grid.Column="0"/>
<Button Grid.Row="1" Grid.Column="1"/>
<Button Grid.Row="1" Grid.Column="2"/>

Maybe something like this:

<Button Grid.Placement="0"/>
<Button Grid.Placement="0,1"/>
<Button Grid.Placement="0,2"/>
<Button Grid.Placement="1"/>
<Button Grid.Placement="1,1"/>
<Button Grid.Placement="1,2"/>

Not sure if this goes too far but I always had the problem that if you want to add a new row or column between existing, you always have to go through ALL children and fix the row / column number. I always asked myself why don't it just take these information from the order in XAML? It would be really great when we can do something like a stackpanel, obviously the syntax is free to change and just for demonstration the idea:

<Grid ColumnDefintions = "Auto,*,*" >
 <Grid.RowDefinitions ChildrenPlacement="Auto">
  <Button Grid.Column="0"/> -- placed in row 0
  <Button Grid.Column="1"/> -- placed in row 1
  <Button Grid.Column="2"/> -- placed in row 2
 </Grid.RowDefinitions>

[thomasclaudiushuber]

@stevenbrix Why even two properties for Rows and Columns? :) I've just played around with a litte project and I came up with an attached property like this:

<Grid local:GridExtensions.Structure="*,100|200,*">

</Grid>

It creates actually this behind the scenes:

<Grid>
  <Grid.RowDefinitions>
    <RowDefinition Height="*"/>
    <RowDefinition Height="100"/>
  </Grid.RowDefinitions>
  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="200"/>
    <ColumnDefinition Width="*"/>
  </Grid.ColumnDefinitions>
  
</Grid>

Here's the repo (Note: It's not production code, I've just hacked it down in a few minutes):
thomasclaudiushuber/Wpf-Grid-Extensions

@dotMorten Adding a brand new property for the shorthand syntax that sets the other properties (RowDef & ColDef) behind the scenes could work as well. I also noticed that the RowDefinitionCollection constructor is not public.

@Symbai Creating an additional Placement-Property to set Row and Column on a Child with 1 string wouldn't be a big deal.

@Symbai Putting elements in rows and columns in the order they appear in XAML doesn't work, or it works, but you won't get what you want. Actually the UniformGrid does this. But to build a typical Window layout there are too many scenarios where you need control, and just the order is not enough to
a) put multiple elements in the same row or column
b) find out whether the next element goes into a column or into a row

@Symbai The last thing you mentioned with "fixing the row number" on an element could be solved with naming. Instead of using numbers, you name Rows and then an element is actually glued to that row.

Note that the Grid is discussed in parallel for UWP here: microsoft/microsoft-ui-xaml#54

[dotMorten]

Adding a brand new property for the shorthand syntax that sets the other properties (RowDef & ColDef) behind the scenes could work as well.

I don't think that's a good story. That gives you two 1st class properties that do the same thing. And as you just demonstrated, you can just use a custom attached property instead then.

[thomasclaudiushuber]

@dotMorten Yes, true, two 1st class properties is not the cleanest way. That would mean we should go the TypeConverter way to get the shorthand syntax directly on the properties RowDefinitions and ColumnDefinitions like shown in the initial comment from @stevenbrix. This means we need to find out how to solve this with the readonly collections like you mentioned already.

[michael-hawker]

Would be nice to coordinate this with the proposed improvements for the UWP Grid for consistency across WPF/UWP: microsoft/microsoft-ui-xaml#54

(just noticed someone else linked to above, sorry for the duplicate, but it'd be a shame to implement two different patterns!)

[thomasclaudiushuber]

@michael-hawker Jep, I added already a reference above to the UWP Grid issue, so that you can see it there.

Now we reached already a point where we notice that there should be something like a XAML Standard for UWP and WPF. Maybe the original XAML Standard Idea between UWP and Xamarin Forms was too much, as these platforms are too far away from each other. But having a standard between UWP and WPF could make a lot of sense.