任务加载图像 [英] Task loading an image

问题描述

我有一个名为Cameleon.png的图像，位于Assert文件夹中。

int我的MainPage_Loaded函数我写的是这样的东西



< pre lang =C＃> void MainPage_Loaded（ object sender，RoutedEventArgs e）
{
任务< writeablebitmap> imtask = GetImage（）;
imtask.ContinueWith（t = >
{
WriteableBitmap writeableBmp = t.Result;
ImageName.Source = writeableBmp;
}）;
}

async 任务< writeablebitmap> GetImage（）
{
string strImageName = string .Format（ ms-appx：///Assets/Cameleon.png）;
Uri uri = new Uri（strImageName）;

WriteableBitmap bitMap = await new WriteableBitmap（ 1 ， 1 ）。FromContent（uri）;
// ImageName.Source = bitMap;
return bitMap;我的XAML文件中的
}

  <  画布 >  
 Image Canvas.Left =0画布.Top =0x：Name =ImageName
 <   / Canvas  < span class =code-keyword>>  

如果我设置ImageName.Source = bitMap;在我的任务函数中它显示图像，但如果在我的MainPage_Loaded函数中设置它不显示。



我做错了什么？



你的帮助非常适合。



祝你好运

Agha Khan

解决方案

这是非常不寻常的行为，但有一个解决方案。 ContinueWith调用需要一个额外的参数。

imtask.ContinueWith（t =>

{



if（t.IsFaulted == false）

{

WriteableBitmap writeableBmp = t.Result;

myImage.Source = writeableBmp;

}

}，TaskScheduler.FromCurrentSynchronizationContext（））;



现在它正常工作。

I have an image called Cameleon.png sitting in Assert Folder.
int my MainPage_Loaded function I write something like this

void MainPage_Loaded(object sender, RoutedEventArgs e)
{
     Task<writeablebitmap> imtask = GetImage();
     imtask.ContinueWith(t =>
     {
            WriteableBitmap writeableBmp = t.Result;
            ImageName.Source = writeableBmp;
     });
}

async Task<writeablebitmap> GetImage()
{
     string strImageName = string.Format("ms-appx:///Assets/Cameleon.png");
     Uri uri = new Uri(strImageName);

     WriteableBitmap bitMap = await new WriteableBitmap(1, 1).FromContent(uri);
        //    ImageName.Source = bitMap;
     return bitMap;
}

in my XAML file

<Canvas>
 Image Canvas.Left="0" Canvas.Top="0" x:Name="ImageName"
</Canvas>

If I set ImageName.Source = bitMap; in my Task function it show the image, but if set in my MainPage_Loaded function it does NOT show.

What I am doing wrong?

Your help will be very much appriciated.

Best regards
Agha Khan

解决方案

This is very unusual behavior, but there is a solution. There is need an extra parameter for ContinueWith call.
imtask.ContinueWith(t =>
{

if (t.IsFaulted == false)
{
WriteableBitmap writeableBmp = t.Result;
myImage.Source = writeableBmp;
}
}, TaskScheduler.FromCurrentSynchronizationContext());

Now it works fine.

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