从字符串到 UserControl 的 TypeConverter [英] TypeConverter from string to UserControl

问题描述

假设在一个 xaml 窗口中我有 <UserControl x:Name="Test">...我有一个自定义 MyListBoxItem，只添加了一个依赖属性 UserControlProperty，typeof UserControl.

Suppose in a xaml window I have <UserControl x:Name="Test">... I have a custom MyListBoxItem with only one dependencyproperty UserControlProperty added, typeof UserControl.

我想使用语法 <c:MyListBoxItem UserControl="Test">Information</c:MyListBoxItem> 但我不知道如何从字符串 "Test" 或者可能是 "local:Test" 到该 xaml 页面上的用户控件测试.

I want to use the syntax <c:MyListBoxItem UserControl="Test">Information</c:MyListBoxItem> and I am not sure how to write a typeconverter from the string "Test" or perhaps "local:Test" to the usercontrol Test on that xaml page.

回答'nit'的评论:

In answer to a comment of 'nit':

<Window.Resources>
    <UserControl x:Key="Test" x:Name="Test"
                 x:Shared="False">
        <Button Height="50"
                Width="50" />
    </UserControl>
</Window.Resources>

使用 <c:MyListBoxItem UserControl="{StaticResource Test}">Information</c:MyListBoxItem> 有效.但是我想要常规 xaml 定义中的 UserControl 并找到了另外两种方法:

with <c:MyListBoxItem UserControl="{StaticResource Test}">Information</c:MyListBoxItem> works. However I wanted the UserControl in the regular xaml definitions and found two other ways of doing it:

<c:MyListBoxItem UserControl="{x:Reference Test}">

但是 x:Reference 给出了编译时错误:方法/操作未实现.它仍然在运行，顺便说一句，imo很奇怪.并且:

However x:Reference gives a complie time error: method/operation not implemented. It still runs which btw is weird imo. And:

<c:MyListBoxItem UserControl="{Binding ElementName=Test}"

这是一个很好的解决方案.

which is the good solution.

至于你可以通过这个实现什么:

As for what you can achieve by this:

private void Menu_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
  foreach (var item in e.RemovedItems)
  {
    // collapse usercontrol
    UserControl uc = (item as MyListBoxItem).UserControl;
    if (uc != null) uc.Visibility = Visibility.Collapsed;
            }
  foreach (var item in e.AddedItems)
  {
     // uncollapse usercontrol
     UserControl uc = (item as MyListBoxItem).UserControl;
     if (uc != null) uc.Visibility = Visibility.Visible;
  }
}

这是支持这种菜单结构的好方法，xaml 定义也很清楚:

This is a nice way to support this kind of menu structure and the xaml definition is also clarifying:

<c:MyListBoxItem UserControl="{Binding ElementName=Information}" IsSelected="True">Information</c:MyListBoxItem>
<c:MyListBoxItem UserControl="{Binding ElementName=Edit}" IsSelected="False">Edit</c:MyListBoxItem>

<Grid>
   <UserControl x:Name="Information" Visibility="Visible"><Button Content="Placeholder for usercontrol Information" /></UserControl>
   <UserControl x:Name="Edit" Visibility="Collapsed"> <Button Content="Placeholder for usercontrol Edit" /></UserControl>

推荐答案

我不确定你想通过这样做达到什么目的，但你必须把那个 UserControl 放在资源中

I am not sure what you want to achieve by doing this, but you will have to put that UserControl in the resources

<Window.Resources>
 <UserControl x:Key="Test" x:Shared="false">
</Window.Resources>

然后你可以将你的DP设置为

Then you can set your DP as

    <c:MyListBoxItem UserControl="{StaticResource Test}">Information</c:MyListBoxItem>

这篇关于从字符串到 UserControl 的 TypeConverter的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！