如何创建包含占位符以供以后使用的WPF用户控件 [英] How to create WPF usercontrol which contains placeholders for later usage
问题描述
我最好以身作则地问这个问题.假设我有使用此控件的UserControl和Window.
我想以这种方式(这是科幻语法!)来设计此控件(名为MyControl):
<Grid>
<Button>Just a button</Button>
<PlaceHolder Name="place_holder/>
</Grid>
并在设计我的窗口时以这种方式使用:
<MyControl/>
或
<MyControl>
<place_holder>
<Button>Button 1</Button>
</place_holder>
</MyControl>
或
<MyControl>
<place_holder>
<Button>Button 1</Button>
<Button>Button 2</Button>
</place_holder>
</MyControl>
当然,我希望能够向Window中的MyControl添加更多元素.因此,在某种程度上,它应该作为容器工作(例如Grid,StackPanel等).放置位置将在UserControl中定义(在此示例中,按钮仅是按钮"之后),而要添加的内容(哪些元素)将在Window中定义(使用UserControl-MyControl-).
我希望这很清楚我想要实现的目标.关键是在设计Window时使用XAML,因此我的类应该不会比其他控件差.
现在,最大的问题是-怎么做?
备注:样式超出范围.我要做的就是在设计Window时将我想要的任何控件添加到MyControl中(而不是在设计MyControl时).
ContentControls& ItemsControls对此很有用,您可以将它们绑定到UserControl的属性或公开它们.
使用ContentControl(用于多个断开连接的位置中的占位符):
<UserControl x:Class="Test.UserControls.MyUserControl2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
Name="control">
<Grid>
<Button>Just a button</Button>
<ContentControl Content="{Binding PlaceHolder1, ElementName=control}"/>
</Grid>
</UserControl>
public partial class MyUserControl2 : UserControl
{
public static readonly DependencyProperty PlaceHolder1Property =
DependencyProperty.Register("PlaceHolder1", typeof(object), typeof(MyUserControl2), new UIPropertyMetadata(null));
public object PlaceHolder1
{
get { return (object)GetValue(PlaceHolder1Property); }
set { SetValue(PlaceHolder1Property, value); }
}
public MyUserControl2()
{
InitializeComponent();
}
}
<uc:MyUserControl2>
<uc:MyUserControl2.PlaceHolder1>
<TextBlock Text="Test"/>
</uc:MyUserControl2.PlaceHolder1>
</uc:MyUserControl2>
ItemsControl-Version(用于一处收藏)
<UserControl x:Class="Test.UserControls.MyUserControl2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
Name="control">
<Grid>
<Button>Just a button</Button>
<ItemsControl Name="_itemsControl" ItemsSource="{Binding ItemsSource, ElementName=control}"/>
</Grid>
</UserControl>
[ContentProperty("Items")]
public partial class MyUserControl2 : UserControl
{
public static readonly DependencyProperty ItemsSourceProperty =
ItemsControl.ItemsSourceProperty.AddOwner(typeof(MyUserControl2));
public IEnumerable ItemsSource
{
get { return (IEnumerable)GetValue(ItemsSourceProperty); }
set { SetValue(ItemsSourceProperty, value); }
}
public ItemCollection Items
{
get { return _itemsControl.Items; }
}
public MyUserControl2()
{
InitializeComponent();
}
}
<uc:MyUserControl2>
<TextBlock Text="Test"/>
<TextBlock Text="Test"/>
</uc:MyUserControl2>
使用UserControls,您可以决定公开内部控件的某些属性;除了ItemsSource
之外,可能还希望公开诸如ItemsControl.ItemTemplate
之类的属性,但是这完全取决于您要如何使用它,如果仅设置Items
,则不一定需要其中的任何一个. /p>
I'd better ask the question by example. Let's say I have UserControl and Window which uses this control.
I would like to design this control (named MyControl) in such way (this is sci-fi syntax!):
<Grid>
<Button>Just a button</Button>
<PlaceHolder Name="place_holder/>
</Grid>
and use in such ways when designing my Window:
<MyControl/>
or
<MyControl>
<place_holder>
<Button>Button 1</Button>
</place_holder>
</MyControl>
or
<MyControl>
<place_holder>
<Button>Button 1</Button>
<Button>Button 2</Button>
</place_holder>
</MyControl>
Of course I would like to have ability to add even more elements to MyControl in Window. So, in a way it should work as container (like Grid, StackPanel, and so on). The placement would be defined in UserControl (in this example after button "Just a button") but what to add (what elements) would be defined in Window (where UserControl -- MyControl -- is used).
I hope this is clear what I would like to achieve. The key point is using XAML when designing Window, so my class should be no worse than other controls.
Now, the big QUESTION is -- how to do it?
Remarks: styling is out of scope. All I want to do is add any controls I want to MyControl when designing Window (not when designing MyControl).
ContentControls & ItemsControls are good for this, you can bind them to a property of your UserControl or expose them.
Using a ContentControl (for placeholders in multiple disconnected places):
<UserControl x:Class="Test.UserControls.MyUserControl2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
Name="control">
<Grid>
<Button>Just a button</Button>
<ContentControl Content="{Binding PlaceHolder1, ElementName=control}"/>
</Grid>
</UserControl>
public partial class MyUserControl2 : UserControl
{
public static readonly DependencyProperty PlaceHolder1Property =
DependencyProperty.Register("PlaceHolder1", typeof(object), typeof(MyUserControl2), new UIPropertyMetadata(null));
public object PlaceHolder1
{
get { return (object)GetValue(PlaceHolder1Property); }
set { SetValue(PlaceHolder1Property, value); }
}
public MyUserControl2()
{
InitializeComponent();
}
}
<uc:MyUserControl2>
<uc:MyUserControl2.PlaceHolder1>
<TextBlock Text="Test"/>
</uc:MyUserControl2.PlaceHolder1>
</uc:MyUserControl2>
ItemsControl-Version (for collections in one place)
<UserControl x:Class="Test.UserControls.MyUserControl2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
Name="control">
<Grid>
<Button>Just a button</Button>
<ItemsControl Name="_itemsControl" ItemsSource="{Binding ItemsSource, ElementName=control}"/>
</Grid>
</UserControl>
[ContentProperty("Items")]
public partial class MyUserControl2 : UserControl
{
public static readonly DependencyProperty ItemsSourceProperty =
ItemsControl.ItemsSourceProperty.AddOwner(typeof(MyUserControl2));
public IEnumerable ItemsSource
{
get { return (IEnumerable)GetValue(ItemsSourceProperty); }
set { SetValue(ItemsSourceProperty, value); }
}
public ItemCollection Items
{
get { return _itemsControl.Items; }
}
public MyUserControl2()
{
InitializeComponent();
}
}
<uc:MyUserControl2>
<TextBlock Text="Test"/>
<TextBlock Text="Test"/>
</uc:MyUserControl2>
With UserControls you can decide to expose certain properties of internal controls; besides the ItemsSource
one probably would want to also expose properties like the ItemsControl.ItemTemplate
, but it all depends on how you want to use it, if you just set the Items
then you do not necessarily need any of that.
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