如何从WPF中的多分辨率.ico文件中选择正确的大小图标?

我使用简单的标记扩展:

/// <summary>
/// Simple extension for icon, to let you choose icon with specific size.
/// Usage sample:
/// Image Stretch="None" Source="{common:Icon /Controls;component/icons/custom.ico, 16}"
/// Or:
/// Image Source="{common:Icon Source={Binding IconResource}, Size=16}"
/// </summary> 
public class IconExtension : MarkupExtension
{
    private string _source;

    public string Source
    {
        get
        {
            return _source;
        }
        set
        {
            // Have to make full pack URI from short form, so System.Uri recognizes it.
           _source = "pack://application:,,," + value;
        }
    }

    public int Size { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        var decoder = BitmapDecoder.Create(new Uri(Source), 
                                           BitmapCreateOptions.DelayCreation,
                                           BitmapCacheOption.OnDemand);

        var result = decoder.Frames.SingleOrDefault(f => f.Width == Size);
        if (result == default(BitmapFrame))
        {
            result = decoder.Frames.OrderBy(f => f.Width).First();
        }

        return result;
    }

    public IconExtension(string source, int size)
    {
        Source = source;
        Size = size;
    }

    public IconExtension() { }
}

XAML用法:

<Image Stretch="None"
       Source="{common:Icon Source={Binding IconResource},Size=16}"/>

或

<Image Stretch="None"
       Source="{common:Icon /ControlsTester;component/icons/custom-reports.ico, 16}" />

似乎不可能只使用XAML。

如果您询问的原因是图标在您看来很模糊,请阅读这篇关于我解决该问题的主题的非常好的文章: http://blogs.msdn.com/dwayneneed/archive/2007/10/05/blurry-bitmaps.aspx

您将不得不使用一个自定义控件,它不仅精确地调整图标的大小,而且确保它与像素网格完全一致。只有这样才能避免插值,从而避免模糊。

试图在您的查询中找到一些关于图标中图像大小选择的信息…如果我找到任何信息,将返回…

(基于@nikolay great answer和后续关于绑定的评论)

你最好创造一个 Converter 而不是 MarkupExtension 这样你就可以利用 Binding . 使用@nikolay提供的相同逻辑

    /// <summary>
    /// Forces the selection of a given size from the ICO file/resource. 
    /// If the exact size does not exists, selects the closest smaller if possible otherwise closest higher resolution.
    /// If no parameter is given, the smallest frame available will be selected
    /// </summary>
    public class IcoFileSizeSelectorConverter : IValueConverter
    {
        public virtual object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            var size = string.IsNullOrWhiteSpace(parameter?.ToString()) ? 0 : System.Convert.ToInt32(parameter);

            var uri = value?.ToString()?.Trim();
            if (string.IsNullOrWhiteSpace(uri))
                return null;

            if (!uri.StartsWith("pack:"))
                uri = $"pack://application:,,,{uri}";

            var decoder = BitmapDecoder.Create(new Uri(uri),
                                              BitmapCreateOptions.DelayCreation,
                                              BitmapCacheOption.OnDemand);

            var result = decoder.Frames.Where(f => f.Width <= size).OrderByDescending(f => f.Width).FirstOrDefault()
                ?? decoder.Frames.OrderBy(f => f.Width).FirstOrDefault();

            return result;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

然后,您必须像往常一样从ResourceDictionary中的某个转换器类创建资源:

<localConverters:IcoFileSizeSelectorConverter x:Key="IcoFileSizeSelector" />

然后你可以用 结合 :

<Image Source="{Binding Path=IconResource, Converter={StaticResource IcoFileSizeSelector}, ConverterParameter=16}" />

PS:在转换器代码中,我们接受参数的所有输入,甚至是丢失或无效的输入。如果像我一样,你喜欢玩实时XAML编辑,这种行为会更方便。