Question

我正在尝试从存储中读取图像（.png / jpg）并在我的Windows Phone 8应用上获取像素值：

    private static BitmapImage LoadBitmap(string iFilename)
    {
        var imgUri = new Uri(iFilename, UriKind.Relative);
        var image = new BitmapImage { CreateOptions = BitmapCreateOptions.None, UriSource = imgUri };

        return image;
    }

    public static string GetColorAttribute(string iFilename)
    {
        // Get Bitmap Image
        var image = LoadBitmap(iFilename);
        var wbmp = new WriteableBitmap(image);
    }

执行时出现异常：

var wbmp = new WriteableBitmap(image);

{System.Reflection.TargetInvocationException：调用目标抛出了异常。 ---＆GT; System.TypeInitializationException：“MyProject”的类型初始值设定项引发了异常。 ---＆GT; System.NullReferenceException：未将对象引用设置为对象的实例。

是否有在Windows Phone 8上处理图像的示例？

Answer 1

您应该使用SetSource类的BitmapImage方法：

private static WriteableBitmap LoadBitmap(string iFilename)
{
    using (var stream = Application.GetResourceStream(new Uri(iFilename, UriKind.Relative)).Stream)
    {
        var bmpi = new BitmapImage();
        bmpi.SetSource(stream);
        bmpi.CreateOptions = BitmapCreateOptions.None;
        WriteableBitmap bmp = new WriteableBitmap(bmpi);
        bmpi.UriSource = null;
        return bmp;
    }
}

public static void GetColorAttribute(string iFilename)
{
    // Get Bitmap Image
    var wbmp = LoadBitmap(iFilename);
}

这篇文章解释了如何在Windows Phone上加载图像（该文章是为Windows Phone 7编写的，但它在WP8中没有改变）：Image Tips for Windows Phone

Windows Phone读取图像和像素值

1 个答案: