如何读取WPF UserControl中传递的参数？

Question

我在WPF中创建了一个用户控件:

<UserControl x:Class="TestUserControl.Controls.GetLatest"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
        <TextBlock Name="theTextBlock"/>
</UserControl>

后面的代码有一个名为"FirstMessage"的参数,它被设置为我的用户控件TextBlock的文本:

public partial class GetLatest : UserControl
{
    public string FirstMessage { get; set; }

    public GetLatest()
    {
        InitializeComponent();
        theTextBlock.Text = this.FirstMessage;
    }
}

在我的主代码中,我可以使用intellisense在我的用户控件中设置FirstMessage参数:

<Window x:Class="TestUserControl.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300"
    xmlns:controls="clr-namespace:TestUserControl.Controls"
    >
    <StackPanel>
        <controls:GetLatest FirstMessage="This is the title"/>
    </StackPanel>
</Window>

但是,它仍然没有设置文本.我已经尝试了Text ="{Binding Path = FirstMessage}"以及我找到的其他语法,但没有任何效果.

如何在用户控件中访问FirstMessage值？

Answer 1

您的绑定方法不起作用,因为您的属性FirstMessage在更新时不会通知.使用依赖属性.见下文:

public partial class GetLatest : UserControl
{
    public static readonly DependencyProperty FirstMessageProperty = DependencyProperty.Register("FirstMessage", typeof(string), typeof(GetLatest));

    public string FirstMessage
    {
        get { return (string)GetValue(FirstMessageProperty); }
        set { SetValue(FirstMessageProperty, value); }
    }

    public GetLatest()
    {
        InitializeComponent();
        this.DataContext = this;
    }

}

XAML:

<UserControl x:Class="TestUserControl.Controls.GetLatest"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <TextBlock Text="{Binding FirstMessage}" />
</UserControl>

每当FirstMessage属性更改时,您的文本块将自行更新.