AttachedProperty(附加属性)和TypeConverter(类型转换器)是两个WPF技术,它们可以扩展或改变控件的行为和外观。附加属性允许我们为控件添加自定义的属性,而类型转换器则允许我们将属性转换为合适的类型或格式。
以下是一个示例,演示了如何将一个字符串类型的属性转换为枚举类型:
1.创建一个枚举类型
public enum MyEnum { Value1, Value2, Value3 }
2.创建一个类型转换器
public class MyEnumTypeConverter : TypeConverter { //判断是否可以将属性转换为MyEnum类型 public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) { if (sourceType == typeof(string)) { return true; } return base.CanConvertFrom(context, sourceType); }
//执行属性转换
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
{
if (value is string)
{
string str = value.ToString();
if (str == "Value1")
{
return MyEnum.Value1;
}
else if (str == "Value2")
{
return MyEnum.Value2;
}
else if (str == "Value3")
{
return MyEnum.Value3;
}
}
return base.ConvertFrom(context, culture, value);
}
}
3.将附加属性和类型转换器关联起来
public static class MyAttachedProperties { public static readonly DependencyProperty MyPropertyProperty = DependencyProperty.RegisterAttached("MyProperty", typeof(string), typeof(MyAttachedProperties), new PropertyMetadata(null, OnMyPropertyChanged));
public static string GetMyProperty(DependencyObject obj)
{
return (string)obj.GetValue(MyPropertyProperty);
}
public static void SetMyProperty(DependencyObject obj, string value)
{
obj.SetValue(MyPropertyProperty, value);
}
private static void OnMyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
//将属性转换