如何读取 WPF UserControl 中传递的参数? [英] How to read a passed parameter in a WPF UserControl?

问题描述

我在 WPF 中创建了一个用户控件:

I created a user control in WPF:

<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，它设置为我的用户控件 TextBlock 的文本:

The code behind has a parameter called "FirstMessage" which it sets as the text of my user control TextBlock:

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

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

在我的主代码中，我可以使用智能感知在我的用户控件中设置 FirstMessage 参数:

In my main code I can set the FirstMessage parameter in my user control with intellisense:

<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.我已经尝试过 Text="{Binding Path=FirstMessage}" 和我发现的其他语法，但没有任何效果.

However, it still doesn't set the text. I've tried Text="{Binding Path=FirstMessage}" and other syntaxes I have found but nothing works.

如何访问用户控件中的 FirstMessage 值?

How can I access the FirstMessage value in my user control?

推荐答案

您的绑定方法不起作用，因为您的属性 FirstMessage 在更新时没有通知.为此使用依赖属性.见下文:

Your approach to binding doesn't work because your property FirstMessage doesn't notify when it gets updated. Use Dependency Properties for that. See below:

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 属性发生变化时，您的文本块都会自行更新.

Whenever the FirstMessage property changes, your text block will update itself.

这篇关于如何读取 WPF UserControl 中传递的参数?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！