用于集合 DP 的 WPF TypeConversionAttribute

发布于 2024-10-19 20:47:54 字数 209 浏览 1 评论 0原文

我有一个 ObservableCollection 作为自定义控件中的依赖属性（例如 Points）。

我想像这样初始化它

<MyControl Points="1,1, 2,2"/>

如何为特定 DP 定义和创建类型转换器？

我知道有一个专门的点集合类，带有内置类型转换器，但我无法使用它。

原文

I have an ObservableCollection as a dependency property(say Points) in a custom control.

I want to initialize it like this

<MyControl Points="1,1, 2,2"/>

How do I go about defining and creating a typeconverter for the specific DP?

I know there is a specialized points collection class with a built in typeconverter but I cannot use it.

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

困倦 2024-10-26 20:47:54

您可以在 CLR 属性包装器上为依赖项属性指定一个 TypeConverter。像这样：

public class MyControl : Control 
{
    [TypeConverter(typeof(MyStringToPointCollectionConverter))]
    public ObservableCollection<Point> Points {
        get { return (ObservableCollection<Point>)GetValue(Points yProperty); }
        set { SetValue(Points Property, value); }
    }
    ...
}

转换器看起来像这样：

public class MyStringToPointCollectionConverter : TypeConverter {
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
        if (sourceType == typeof(string)) {
            return true;
        }

        return false;
    }

    public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value) {
        var stringValue = value as string;

        if (stringValue != null) {
            var result = new ObservableCollection<Point>();

            // Here goes the logic of converting the given string to the list of points

            return result;
        }

        return null;
    }
}

You can specify a TypeConverter on the CLR property wrapper for your dependency property. Like this:

public class MyControl : Control 
{
    [TypeConverter(typeof(MyStringToPointCollectionConverter))]
    public ObservableCollection<Point> Points {
        get { return (ObservableCollection<Point>)GetValue(Points yProperty); }
        set { SetValue(Points Property, value); }
    }
    ...
}

And the converter would look something like this:

public class MyStringToPointCollectionConverter : TypeConverter {
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
        if (sourceType == typeof(string)) {
            return true;
        }

        return false;
    }

    public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value) {
        var stringValue = value as string;

        if (stringValue != null) {
            var result = new ObservableCollection<Point>();

            // Here goes the logic of converting the given string to the list of points

            return result;
        }

        return null;
    }
}

回复收藏 0 原文