Create a generic list in xaml 4.5+

Question

I am trying to make a rule list for one of my usercontrols. List contains a custom type List<StringInputRule>. I am using DependancyProperty to databind.

I am trying to set the rules in xaml for the control as such:

<controlsDefault:DateEditWithStringInput>
    <controlsDefault:DateEditWithStringInput.Rules>
       <x:Array Type="controlsDefault:StringInputRule" xmlns:sys="clr-namespace:System;assembly=mscorlib">
            <controlsDefault:StringInputRule Key="T" Amount="1" Unit="Day"/>
            <controlsDefault:StringInputRule Key="W" Amount="1" Unit="Week"/>
            <controlsDefault:StringInputRule Key="M" Amount="1" Unit="Month"/>
       </x:Array>
     </controlsDefault:DateEditWithStringInput.Rules>
</controlsDefault:DateEditWithStringInput>

c# code for dependancy property for the control:

public partial class DateEditWithStringInput : UserControl
{
    public DateEditWithStringInput()
    {
        InitializeComponent();
        Rules = new List<StringInputRule>();
    }

    public IList<StringInputRule> Rules
    {
        get { return (IList<StringInputRule>)GetValue(RulesProperty); }
        set { SetValue(RulesProperty, value); }
    }

    public static readonly DependencyProperty RulesProperty =
        DependencyProperty.Register("Rules", typeof(IList<StringInputRule>), typeof(DateEditWithStringInput), new PropertyMetadata(new List<StringInputRule>()));
}

So the following approach does not pass any values, yet it compiles. I have read that generic types could be initialized within xaml from 2009 version with 4.0, yet I could have not located an example.

My question: How to define generic List in xaml?

Edit: As to this day there is no solid solution to the problem.

WorkAround (as pointed by Szabolcs Dézsi): how use List<T> within xaml?

score 0 · Accepted Answer · edited May 23 '17 at 10:31

0

It would look like this:

<controlsDefault:DateEditWithStringInput.Rules>
    <generic:List x:TypeArguments="controlsDefault:StringInputRule">
        <controlsDefault:StringInputRule Key="T" Amount="1" Unit="Day"/>
        <controlsDefault:StringInputRule Key="W" Amount="1" Unit="Week"/>
        <controlsDefault:StringInputRule Key="M" Amount="1" Unit="Month"/>
    </generic:List>
</controlsDefault:DateEditWithStringInput.Rules>

x:TypeArguments is a XAML 2009 feature. Unfortunately it's not supported in compiled XAML, so you won't be able to use it in your WPF application. Read more here, here and here.

edited May 23 '17 at 10:31

Community

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answered Feb 03 '16 at 18:58

Szabolcs Dézsi

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Unfortunately, I cannot mark this as an answer since it just states the fact that you cannot do it, yet I have actually already solved it by adding additional non generic type which inherits from List and use child class as type. You can alter your answer accordingly and I will mark it as an answer. Have a good day! – Karolis Kajenas Feb 04 '16 at 07:43
1

Yes, I know about that, the question is a duplicate anyway: http://stackoverflow.com/a/7152297/4620101 although I feel this is a workaround and not an answer for your specific question: "How to define generic List in xaml?" – Szabolcs Dézsi Feb 04 '16 at 08:30
Initially I was looking for a more solid way to do it as you mentioned in the comment, that is why I written this questions. Apparently, you cannot do without that workaround :) Thanks for the effort! – Karolis Kajenas Feb 04 '16 at 08:52

Create a generic list in xaml 4.5+

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