private async Task TakeImage()
{
var cameraOpts = new CameraMediaStorageOptions();
cameraOpts.PercentQuality = 50;
cameraOpts.MaxPixelDimension = 1200;
var result = await UIUtils.ShowSelectList("Take a photo", "Choose from library", this);
System.Threading.Tasks.Task <MediaFile> taskMedia = null;
if (result == 1)
{
taskMedia = DependencyService.Get <IMediaPicker>().TakePhotoAsync(cameraOpts);
}
else if (result == 2)
{
taskMedia = DependencyService.Get <IMediaPicker>().SelectPhotoAsync(cameraOpts);
}
else
{
return;
}
await taskMedia.ContinueWith((t, o) =>
{
if (t.IsCanceled || t.Result == null)
{
return;
}
photoFile = t.Result;
}, null);
}
private void btnTaskSub_Click(object sender, EventArgs e)
{//前面提到了，当你等待一个任务的时候，同时需要等待它的子任务完成。
//下面代码演示了带子任务的Task：
System.Threading.Tasks.Task <int[]> parentTask = System.Threading.Tasks.Task.Factory.StartNew(() =>
{
int[] results = new int[3];
System.Threading.Tasks.Task t1 = new System.Threading.Tasks.Task(() =>
{ System.Threading.Thread.Sleep(3000); results[0] = 0; }, TaskCreationOptions.AttachedToParent);
System.Threading.Tasks.Task t2 = new System.Threading.Tasks.Task(() =>
{ System.Threading.Thread.Sleep(3000); results[1] = 1; }, TaskCreationOptions.AttachedToParent);
System.Threading.Tasks.Task t3 = new System.Threading.Tasks.Task(() =>
{ System.Threading.Thread.Sleep(3000); results[2] = 2; }, TaskCreationOptions.AttachedToParent);
t1.Start();
t2.Start();
t3.Start();
return(results);
});
System.Threading.Tasks.Task finalTask = parentTask.ContinueWith(parent =>
{
foreach (int result in parent.Result)
{
Console.WriteLine(result);
}
});
finalTask.Wait();
Console.ReadLine();
//这段代码的输出结果是： 1,2,3
//FinalTask会等待所有子Task结束后再执行。
}
/// <summary>
///
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="path">Excel文件路径</param>
/// <param name="objectProps">转换规则</param>
/// <param name="worksheetIndex">获取工作表Index 默认获取第一张工作表内容( Index = 0 )</param>
/// <param name="isContainLieDingYi">是否含有列定义行， 默认true</param>
/// <param name="lieDingYi_RowIndex">首位列定义 RowIndex</param>
/// <param name="lieDingYi_ColumnIndex">首位列定义 ColumnIndex</param>
/// <returns></returns>
public void WorkSheet2ListAsync <T>(Action <Task <List <T> > > actionHandler, string path, List <PropertyColumn> objectProps, int worksheetIndex = 0,
bool isContainLieDingYi = true, int lieDingYi_RowIndex = 0, int lieDingYi_ColumnIndex = 0, bool ignoreRepeatColumnName = false
) where T : class, new()
{
Task <List <T> > mTask = new System.Threading.Tasks.Task <List <T> >(() => WorkSheet2List <T>
(
path: path,
objectProps: objectProps,
worksheetIndex: worksheetIndex,
isContainLieDingYi: isContainLieDingYi,
lieDingYi_RowIndex: lieDingYi_RowIndex,
lieDingYi_ColumnIndex: lieDingYi_ColumnIndex,
ignoreRepeatColumnName: ignoreRepeatColumnName
)
);
mTask.ContinueWith((task) => actionHandler(task));
mTask.Start();
#region (UI代码参考)下载完毕 Handler 可以参考以下代码
//public void DownloadFileByHttpRequestAynsc_Handler(System.Threading.Tasks.Task task)
//{
// string msg = "IsCanceled={0}\nIsCompleted={1}\nIsFaulted={2};"
// .FormatWith
// (
// task.IsCanceled, // 因被取消而完成
// task.IsCompleted, // 成功完成
// task.IsFaulted // 因发生异常而完成
// );
// Console.WriteLine(msg);
// if (task.IsFaulted == true)
// {
// if (task.Exception != null)
// {
// Console.WriteLine(task.IsFaulted);
// MessageBox.Show(task.Exception.GetFullInfo());
// }
// else
// {
// MessageBox.Show("下载失败。");
// }
// }
// else
// {
// MessageBox.Show("下载完成。");
// }
//}
#endregion
}
public void SaveAsyncOrShowError(ProjectGroup projectGroup)
{
System.Threading.Tasks.Task <bool> task = SaveAsync(projectGroup);
task.ContinueWith((t) =>
{
if (!t.Result)
{
MessageBox.Show("Failed to save project changes on disk.", "Error",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
});
}
private void _Read()
{
System.Threading.Tasks.Task <int> task = _Peer.Receive(_ReadedByte, 0, 1);
task.ContinueWith(t => _Readed(t));
}
static public void ContinueTask(System.Threading.Tasks.Task <object> task, object state)
{
// Will complete asynchronously. Schedule continuation to finish processing.
task.ContinueWith(new Action <System.Threading.Tasks.Task <object>, object>(edgeAppCompletedOnCLRThread), state);
}
