wpf 命令自定义控件绑定 xaml答案

【问题标题】：wpf command custom control binding xamlwpf 命令自定义控件绑定 xaml
【发布时间】：2010-12-26 17:34:45
【问题描述】：

我正在构建一个 Videoplayer 自定义控件（名为 WpfCustomControlLibrary1 的项目）并希望添加一个加载命令。

这是我在课堂上添加的用于获取此命令的内容：

Public Class VideoPlayer
Inherits Control
...
Public Shared ReadOnly LoadCommad As RoutedUICommand
....

Shared Sub New()
    'This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.
    'This style is defined in Themes\Generic.xaml
    DefaultStyleKeyProperty.OverrideMetadata(GetType(VideoPlayer), New FrameworkPropertyMetadata(GetType(VideoPlayer)))

    LoadCommad = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))
    CommandManager.RegisterClassCommandBinding(GetType(VideoPlayer), New CommandBinding(LoadCommad, AddressOf OnLoadExecuted))
End Sub
...

这就是我从我的 XAML 中调用它的方式：

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfCustomControlLibrary1">
.....
<Button Command="local:VideoPlayer.LoadCommand"
        DockPanel.Dock="Right" Margin="0 5 5 0"
        Width="30" HorizontalAlignment="Left"
        Content="..." />
.....

但是当我将此用户控件添加到这样的新项目时：

<Window x:Class="Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:bibli="clr-namespace:EigeneControllsBibli;assembly=EigeneControllsBibli"
xmlns:uc="clr-namespace:WpfCustomControlLibrary1;assembly=WpfCustomControlLibrary1"
Title="Window1" Height="442" Width="804">
<Grid>
    <uc:VideoPlayer Source="C:\Users\Public\Videos\Sample Videos\Bear.wmv" Margin="0,106,369,0"></uc:VideoPlayer>
</Grid>

我得到一个错误，他无法将属性“命令”中的字符串转换为“System.Windows.Input.ICommand”类型的对象

有人知道出了什么问题吗？

感谢您的帮助，妮可

【问题讨论】：

标签： wpf vb.net xaml command custom-controls

【解决方案1】：

你有一个拼写错误：

LoadCommad = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))

应该是

LoadCommand = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))

我不知道这是否会产生错误，但也许。

【讨论】：

【解决方案2】：

我认为你想要做的是将 LoadCommand 声明为实例而不是共享变量，所以：

Public Class VideoPlayer
Inherits Control
...
Private ReadOnly m_LoadCommand As RoutedUICommand
....

Shared Sub New()
    'This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.
    'This style is defined in Themes\Generic.xaml
    DefaultStyleKeyProperty.OverrideMetadata(GetType(VideoPlayer), New FrameworkPropertyMetadata(GetType(VideoPlayer)))
End Sub

Sub New()
    m_LoadCommand = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))
End Sub

Public Property LoadCommand As ICommand
   Get
      Return m_LoadCommand
   End Get
End Property 
...

然后在 XAML 中绑定 Button.Command 属性，所以：

<StackPanel>
    <uc:VideoPlayer x:Name="myPlayer" Source="C:\Users\Public\Videos\Sample Videos\Bear.wmv" Margin="0,106,369,0"></uc:VideoPlayer>
    <Button Command="{Binding ElementName=myPlayer, Path=LoadCommand"
        Width="30"
        Content="..." />
</StackPanel>

【讨论】：