Question

我几天来一直在努力解决这个问题。为什么我会得到＆＃34; Value does not fall within the expected range＆＃34;此转换方法中的异常？（它的Windows Phone 8.1 app）

public static async Task<string> ConvertToBase64(this BitmapImage bitmapImage)
{
    RandomAccessStreamReference rasr = RandomAccessStreamReference.CreateFromUri(bitmapImage.UriSource);
    var streamWithContent = await rasr.OpenReadAsync(); //raises an exception
    byte[] buffer = new byte[streamWithContent.Size];
    var result = await streamWithContent.ReadAsync(buffer.AsBuffer(), (uint)streamWithContent.Size, InputStreamOptions.None);
    using (MemoryStream ms = new MemoryStream(result.ToArray()))
    {
        return Convert.ToBase64String(ms.ToArray());
    }
}

我从资源中检索图像：

Photo = new BitmapImage(new Uri("ms-appx:///Assets/pies.jpg", UriKind.RelativeOrAbsolute));
        newOffer.PhotoBase64 = await Photo.ConvertToBase64();

Answer 1

这似乎是BitmapImage.UriSource中的错误 - 它返回了无效的URI：

var u1 = new Uri("ms-appx:///Assets/Logo.scale-240.png");
var u2 = new Uri("ms-appx:///Assets/Logo.scale-240.png");

// doesn't assert, because they are equal
Debug.Assert(u1 == u2, "URIs don't match"); 

BitmapImage bi = new BitmapImage(u1);
var u3 = bi.UriSource;

// asserts, because they are not equal
Debug.Assert(u1 == u3, "URIs don't match");

在这种情况下，u3包含ms-appx:/Assets/Logo.scale-240.png - 错过了额外的斜杠。你可以像这样解决：

var fixedUri = new Uri(u3.Scheme + "://" + u3.AbsolutePath);

＆＃34;价值不在预期范围内＆＃34;打开RandomAccessStream时

1 个答案: