Question

我想创建一个WPF用户控件，公开一个名为InnerCaption的属性。代码在

之下

XAML代码

<UserControl x:Class="myControl.UserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Grid>
        <TextBlock Name="_innerCaption" > Hello</TextBlock>
    </Grid>
</UserControl>

CS代码

namespace myControl
{
    /// <summary>
    /// Interaction logic for UserControl1.xaml
    /// </summary>
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        public TextBlock InnerCaption
        {
        get { return (TextBlock)this.GetValue(InnerCaptionProperty); }
        set { this.SetValue(InnerCaptionProperty, value); }
        }
        public static readonly DependencyProperty InnerCaptionProperty = DependencyProperty.Register(
        "InnerCaption", typeof(TextBlock), typeof(UserControl1),new PropertyMetadata(false));
        }
}

问题是：我希望用户能够在设计时自定义InnerCaption，例如：修改其颜色，字体样式......但我不知道叹了口气使用某种Binding。但这是徒劳的。据我所知，Binding仅支持绑定到属性，对吧？给我看一个方法！ :(

Answer 1

绑定如下所示：

XAML

<UserControl x:Class="myControl.UserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Grid>
        <TextBlock Name="_innerCaption" 
                   Text="{Binding MyCaption}"/>
    </Grid>
</UserControl>

现在您必须将XAML文件的DataContext设置为您要绑定到的类：

namespace myControl
{
    /// <summary>
    /// Interaction logic for UserControl1.xaml
    /// </summary>
    public partial class UserControl1 : UserControl
    {
        MyClassToBindTo bindingClass;

        public UserControl1()
        {
            InitializeComponent();
            bindingClass = new MyClassToBindTo();
            DataContext = bindingClass;
        }
   }
}

绑定类可能如下所示：

public class MyClassToBindTo : NotifyPropertyChangedBase
{
        private string myCaptionString = "hello";

        public string MyCaption
        {
        get { return myCaptionString }
        set { myCaptionString = value; OnPropertyChanged("MyCaptionString"); }
        }

        // Also implement the INotifyPropertyChanged interface here
}

希望这能帮到你！

修改

我通常在基类“NotifyPropertyChangedBase：
中实现INotifyPropertyChanged内容
public abstract class PropertyChangedBase : INotifyPropertyChanged { #region Member Variables private static HashSet<string> alreadyCoveredProperties = new HashSet<string>(); #endregion #region INotifyPropertyChanged Members /// <summary> /// Occurs when a property value changes. /// </summary> public event PropertyChangedEventHandler PropertyChanged; /// <summary> /// Calls registered handlers when a property is changed. /// </summary> /// <param name="propertyName">Name of the property.</param> protected void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = this.PropertyChanged; if (handler != null) { handler(this, new PropertyChangedEventArgs(propertyName)); } } /// <summary> /// Removes all property changed subscription from the event handler. /// </summary> protected void RemovePropertyChangedSubscription() { if (this.PropertyChanged != null) { this.PropertyChanged -= new PropertyChangedEventHandler(PropertyChanged); this.PropertyChanged = null; } } /// <summary> /// Determines whether the specified property name refers to a property defined for this object. /// </summary> /// <param name="propertyName">Name of the property.</param> /// <returns> /// Returns <c>true</c> if the provided name refers to a defined property; otherwise, <c>false</c>. /// </returns> /// <remarks>Uses reflection.</remarks> protected bool IsDefinedPropertyName(string propertyName) { string propertyFullName = GetType().FullName + "." + propertyName; if (alreadyCoveredProperties.Contains(propertyFullName)) { return true; } else { PropertyDescriptorCollection col = TypeDescriptor.GetProperties(this); PropertyDescriptor propertyDescriptor = col[propertyName]; // A property exists, if the propertyDescriptor is != null. if (propertyDescriptor != null) { alreadyCoveredProperties.Add(propertyFullName); return true; } else { return false; } } } #endregion }

Answer 2

我认为你可能会想到的可能是对TextBlock进行子类化的更多内容，这将允许您轻松地使用该控件上的现有属性。

public class MyCaptionControl : TextBlock
{
 ....
}

这使您可以像平常一样进行绑定：

<MyCaptionControl FontSize="{Binding MyModelSize}" Text="{Binding MyModelCaption}" />

你肯定是在正确的方向创建一个依赖属性，但如果你想绑定到这些属性，你需要每个可绑定值一个属性。像

public static readonly DependencyProperty ForegroundColor = ....
public static readonly DependencyProperty BackgroundColor = ....

然后可以将这些直接映射到用户控件中的任何内部文本块控件，但正如我所提到的，我认为你会更好地继承TextBlock。

Answer 3

上面的问题有一个简单的解决方案：如何使用ContentPresenter控件？只需几行代码声明您的属性（TextBlock，string，...），然后将控件绑定到属性。我试过了，它的确有效！：D

WPF绑定问题

3 个答案: