C# 在UWP中将可写位图图像转换为阵列
我正在从azure服务上的blob存储访问映像。我返回图像的C# 在UWP中将可写位图图像转换为阵列,c#,uwp,writeablebitmap,C#,Uwp,Writeablebitmap,我正在从azure服务上的blob存储访问映像。我返回图像的uri,然后使用HttpClient尝试下载它。验证uri是否正确 using (HttpClient client = new HttpClient()) { try { HttpResponseMessage response = await client.GetAsync(new Uri(((App)Application.Current).results.statsInformation.Ima
uri
,然后使用HttpClient尝试下载它。验证uri
是否正确
using (HttpClient client = new HttpClient())
{
try
{
HttpResponseMessage response = await client.GetAsync(new Uri(((App)Application.Current).results.statsInformation.ImageBlob.ImageUri, UriKind.RelativeOrAbsolute));
if (response != null && response.StatusCode == HttpStatusCode.OK)
{
using (var stream = await response.Content.ReadAsStreamAsync())
{
using (var memStream = new MemoryStream())
{
await stream.CopyToAsync(memStream);
memStream.Position = 0;
memStream.Seek(0, SeekOrigin.Begin);
myOnlineImage.SetSource(memStream.AsRandomAccessStream());
}
}
}
}
catch (Exception)
{
throw;
}
}
来自服务器的图像存储在变量myOnlineImage
中。然后我想使用myOnlineImage.PixelBuffer.ToArray()提取像素信息代码>。这是因为图像未正确下载吗?有人能帮我解决这个问题吗
我收到的例外情况是:
例外情况
消息“值不能为空。\r\n参数名称:源”
StackTrace”在System.Runtime.InteropServices.Marshall.CopyToManaged(IntPtr源、对象目标、Int32 startIndex、Int32长度)\r\n在System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions.CopyTo(IBuffer源、UInt32源索引、字节[]目标、Int32目标索引、Int32计数)\r\n位于System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions.ToArray(IBuffer source,UInt32 sourceIndex,Int32 count)\r\n位于System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions.ToArray(IBuffer source)\r\n位于Stonegaard\u Ungulard\u runner.MainPage.d\u 7.MoveNext()
额外的
我已检查是否具有对映像的线程访问权限。在某些情况下,您不能使用System.Runtime.InteropServices
。
指针myOnlineImage.PixelBuffer
为空。
您可以使用BitmapImage
但不能使用WriteableBitmap
并将其转换为byte[]
BitmapDecoder
,BitmapFrame
,PixelDataProvider
如msdn示例:
byte[] image_array = null;
int image_array_width = 0;
int image_array_height = 0;
using (HttpClient client = new HttpClient())
{
try
{
HttpResponseMessage response = await client.GetAsync(new Uri("http://www.example.com/logo.png", UriKind.RelativeOrAbsolute));
if (response != null && response.StatusCode == HttpStatusCode.OK)
{
using (Stream stream = await (response.Content.ReadAsStreamAsync()))
{
using (IRandomAccessStream strm = stream.AsRandomAccessStream())
{
strm.Seek(0);
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(strm);
BitmapFrame bitmapFrame = await decoder.GetFrameAsync(0);
// Get the pixels
var transform = new BitmapTransform { ScaledWidth = decoder.PixelWidth, ScaledHeight = decoder.PixelHeight };
PixelDataProvider dataProvider =
await bitmapFrame.GetPixelDataAsync(BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Straight,
transform,
ExifOrientationMode.RespectExifOrientation,
ColorManagementMode.ColorManageToSRgb);
await strm.FlushAsync();
image_array = dataProvider.DetachPixelData();
image_array_width = (int)decoder.PixelWidth;
image_array_height = (int)decoder.PixelHeight;
}
}
}
}
catch (Exception)
{
throw;
}
}
图像不是文件,而是来自服务器或其他bitmapImage。您知道如何转换这些内容以测试代码吗?@JTIM将using替换为await文件,方法是:using(Stream-Stream=await(response.Content.ReadAsStreamAsync()){using(irandomaccesstream-Stream-Stream=Stream.AsRandomAccessStream()){……行bi.SetSource(strm)时,它会冻结
已执行。之后什么也没有发生?图像大小正确,但像素数据似乎完全是0,0,0255。我更改了代码。图像的尺寸缺少转换!我删除了无用的BitmapImage。它对我有效。