如何將Base64字符串轉換為圖像，然后將其綁定到Metro風格應用程序中的GridView？

Question

我收集了來自Web服務的產品，我在網格視圖中預覽了這個產品，但是我將產品的圖像作為Base64字符串。 如何將其轉換為圖像並將其綁定到網格視圖中的圖像？

任何能幫助我解決這個問題的代碼。

Answer 1

這似乎對我有用：

    public static BitmapImage Base64StringToBitmap(string source)
    {
        var ims = new InMemoryRandomAccessStream();
        var bytes = Convert.FromBase64String(source);
        var dataWriter = new DataWriter(ims);
        dataWriter.WriteBytes(bytes);
        dataWriter.StoreAsync();
        ims.Seek(0);
        var img = new BitmapImage();
        img.SetSource(ims);
        return img;
    }

注意我沒有等待任何東西，img.SetSource應該負責延遲加載。

Answer 2

下面是將Base64String綁定到Image控件的方法

1. 將字符串轉換為byte []，如下所示

    byte[] bytes = System.Convert.FromBase64String(thebase64string); 

2. 傳遞要將Image綁定到的byte []和Image控件。

    public async void SetImageFromByteArray(byte[] data, Windows.UI.Xaml.Controls.Image image) { InMemoryRandomAccessStream raStream = new InMemoryRandomAccessStream(); DataWriter writer = new DataWriter(raStream); // Write the bytes to the stream writer.WriteBytes(data); // Store the bytes to the MemoryStream await writer.StoreAsync(); await writer.FlushAsync(); // Detach from the Memory stream so we don't close it writer.DetachStream(); raStream.Seek(0); BitmapImage bitMapImage = new BitmapImage(); bitMapImage.SetSource(raStream); image.Source = bitMapImage; } 

Answer 3

在WPF / Metro / Silverlight中，Image是一個UI控件。 它的源設置為BitmapSource。 BitmapSource是一種用於保存圖像數據的數據結構。

以下是從字節數組中檢索BitmapImage的代碼。

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

請注意，stream.AsRandomAccessStream在API中不可用它是一種擴展方法。 我從IDWMaster的回答中發現了這個問題

以下是擴展方法的代碼

 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種方法未實施

我沒有測試，但上面應該在校長工作（可能是經過一些改進）。

Answer 4

嘗試這樣的事情：

byte[] encodedDataAsBytes = System.Convert.FromBase64String(encodedData);
MemoryStream stream = new MemoryStream(encodedDataAsBytes.Length);
stream.Write(encodedDataAsBytes, 0, encodedDataAsBytes.Length);
Image img = Image.FromStream(stream);

我沒有使用過地鐵，所以我無法幫助綁定到網格..最好的問候。