如何引用泛型类型的HierarchicalDataTemplate的数据类型属性? [英] How to reference a generic type in the DataType attribute of a HierarchicalDataTemplate?
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问题描述
我有一类 MyClass的<为MyObject>
,并希望将其设置为数据类型为HierarchicalDataTemplate
什么是XAML的语法呢? (我知道如何设置的命名空间,我需要的只是语法
< HierarchicalDataTemplate数据类型={X:类型.....
解决方案
itowlson的做法是一个很好的,但它仅仅是一个开始。这里的东西,将你的情况下工作(大多数,如果不是全部,例):
公共类GenericType:的MarkupExtension
{
公共类型基本类型{获取;组; }
公共类型[] InnerTypes {获得;组; }
公共GenericType(){}
公共GenericType(类型基本类型,PARAMS类型[] innerTypes)
{
BASETYPE =基本类型;
InnerTypes = innerTypes;
}
公众覆盖对象ProvideValue(的IServiceProvider的ServiceProvider)
{
类型结果= BaseType.MakeGenericType(InnerTypes);
返回结果;
}
}
然后,你可以创建任何类型的,在你的XAML任意的深度。例如:
< Grid.Resources>
< X:数组类型={X:键入sys:类型}
X:关键=TypeParams>
< X:类型类型名=SYS:的Int32/>
< / X:阵列>
<地方:GenericType BASETYPE ={X:类型类型名=科尔:List`1}
InnerTypes ={的StaticResource TypeParams}
X:关键=ListOfInts/>
< X:数组类型={X:键入sys:类型}
X:关键=DictionaryParams>
< X:类型类型名=SYS:的Int32/>
<地方:GenericType BASETYPE ={X:类型类型名=科尔:List`1}
InnerTypes ={的StaticResource TypeParams}/>
< / X:阵列>
<地方:GenericType BASETYPE ={X:类型类型名=科尔:Dictionary`2}
InnerTypes ={的StaticResource DictionaryParams}
X:关键=DictionaryOfIntsToListOfInts/>
< /Grid.Resources>
有几个关键的想法在这里:
- 在泛型类型必须使用标准的'符号指定。因此, System.Collections.Generic.List<> 是 System.Collections.Generic.List`1 。字符`表示该类型是通用的和之后的数字表示通用参数的类型具有的数目。
- 的X:类型标记扩展能够很容易地检索这些基地一般类型 。
- 的泛型参数类型传递类型对象的数组。这个数组,然后传递到MakeGenericType(...)调用。
I have a class of MyClass<MyObject>
and want to set it as the DataType for a HierarchicalDataTemplate.
What is the syntax for this in XAML? (I know how to set namespaces, I need just the syntax for
<HierarchicalDataTemplate DataType="{X:Type .....
解决方案
itowlson's approach is a good one but it is just a start. Here's something that will work for your case (and most, if not all, cases):
public class GenericType : MarkupExtension
{
public Type BaseType { get; set; }
public Type[] InnerTypes { get; set; }
public GenericType() { }
public GenericType(Type baseType, params Type[] innerTypes)
{
BaseType = baseType;
InnerTypes = innerTypes;
}
public override object ProvideValue(IServiceProvider serviceProvider)
{
Type result = BaseType.MakeGenericType(InnerTypes);
return result;
}
}
Then, you are able to create any type with any level of depth in your XAML. For example:
<Grid.Resources>
<x:Array Type="{x:Type sys:Type}"
x:Key="TypeParams">
<x:Type TypeName="sys:Int32" />
</x:Array>
<local:GenericType BaseType="{x:Type TypeName=coll:List`1}"
InnerTypes="{StaticResource TypeParams}"
x:Key="ListOfInts" />
<x:Array Type="{x:Type sys:Type}"
x:Key="DictionaryParams">
<x:Type TypeName="sys:Int32" />
<local:GenericType BaseType="{x:Type TypeName=coll:List`1}"
InnerTypes="{StaticResource TypeParams}" />
</x:Array>
<local:GenericType BaseType="{x:Type TypeName=coll:Dictionary`2}"
InnerTypes="{StaticResource DictionaryParams}"
x:Key="DictionaryOfIntsToListOfInts" />
</Grid.Resources>
There's a few key ideas here:
- A generic type has to be specified using the standard ` notation. So, System.Collections.Generic.List<> is System.Collections.Generic.List`1. The character ` indicates that the type is generic and the number after it indicates the number of generic parameters the type has.
- The x:Type markup extension is able to retrieve these base generic types quite easily.
- The generic parameter types are passed as an array of Type objects. This array is then passed into the MakeGenericType(...) call.
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