如何Base64编码字符串转换成图像，然后将其绑定到GridView控件中的Metro风格应用？ [英] How to convert Base64 string to image, then bind it to GridView in a Metro Style App?

问题描述

我已经从web服务的产品集合，我预览网格视图这个产品，但我得到的产品为Base64字符串的图像。我怎样才能将其转换为图像，并将其绑定到网格视图的图像？

I have collection of products from web service, I preview this product in Grid View, but I get the images of the products as Base64 strings. How can I convert it to images and bind it to the images in the Grid View?

任何一段代码，这将帮助我在这个问题上。

Any piece of code that will help me in this issue.

推荐答案

在WPF /地铁/ Silverlight的，形象是一个UI控件。它的源设置为的BitmapSource。的BitmapSource是一个数据结构来保存的图像数据。

In WPF/Metro/Silverlight, Image is a UI control. Its source is set to BitmapSource. BitmapSource is a data structure to hold image data.

以下是从字节数组检索的BitmapImage的代码。

Following is the code to retrieve BitmapImage from byte array.

public BitmapImage ImageFromBuffer(Byte[] bytes)
    {
        MemoryStream stream = new MemoryStream(bytes);
        BitmapImage image = new BitmapImage();
        image.SetSource ( stream.AsRandomAccessStream());
        return image;
    }

注意stream.AsRandomAccessStream是不是在API可用这是一个扩展方法。我发现它从 IDWMaster 本的 SO质疑

下面是扩展方法

 public static class MicrosoftStreamExtensions
    {
        public static IRandomAccessStream AsRandomAccessStream(this Stream stream)
        {
            return new RandomStream(stream);
        }
    }
    class RandomStream : IRandomAccessStream
    {
        Stream internstream;
        public RandomStream(Stream underlyingstream)
        {
            internstream = underlyingstream;
        }
        public IInputStream GetInputStreamAt(ulong position)
        {
            internstream.Position = (long)position;
            return internstream.AsInputStream();
        }

        public IOutputStream GetOutputStreamAt(ulong position)
        {
            internstream.Position = (long)position;
            return internstream.AsOutputStream();
        }

        public ulong Size
        {
            get
            {
                return (ulong)internstream.Length;
            }
            set
            {
                internstream.SetLength((long)value);
            }
        }

        public bool CanRead
        {
            get { return internstream.CanRead; }
        }

        public bool CanWrite
        {
            get { return internstream.CanWrite; }
        }

        public IRandomAccessStream CloneStream()
        {
            //HACK, this is not clone, proper implementation is required, returned object will share same internal stream
            return new RandomStream(this.internstream);
        }

        public ulong Position
        {
            get { return (ulong)internstream.Position; }
        }

        public void Seek(ulong position)
        {
            internstream.Seek((long)position, SeekOrigin.Current);
        }

        public void Dispose()
        {
            internstream.Dispose();
        }

        public Windows.Foundation.IAsyncOperationWithProgress<IBuffer, uint> ReadAsync(IBuffer buffer, uint count, InputStreamOptions options)
        {
            throw new NotImplementedException();
        }

        public Windows.Foundation.IAsyncOperation<bool> FlushAsync()
        {
            throw new NotImplementedException();
        }

        public Windows.Foundation.IAsyncOperationWithProgress<uint, uint> WriteAsync(IBuffer buffer)
        {
            throw new NotImplementedException();
        }
    }

最后3个方法不落实

Last 3 methods are not implemented

我没有测试过，但上面的应该主要工作（可能是一些细化后）。

I have not tested but above should work in principal (may be after some refinement).

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