在MvxBindableTableViewCell
. 我在 iOS 上使用 MvvmCross 的 vNext 分支。
一切都已正确设置,并且在首次加载/显示列表时可以看到初始值。该列表是 aObservableCollection<T>
并且 ViewModels 继承自MvxViewModel
(因此实现了 INotifyPropertyChanged)。
主视图模型如下所示:
public abstract class BaseViewModel : MvxViewModel, IMvxServiceConsumer
{
//... just regular implementation
}
public class UploadListViewModel: BaseViewModel
{
private readonly IUploadItemTasks uploadItemTasks;
private readonly IPhotoPickerService photoPickerService;
public IObservableCollection<UploadItemViewModel> Uploads { get { return this.LoadUploadItems(); } }
public UploadListViewModel()
{
this.uploadItemTasks = this.GetService<IUploadItemTasks>();
this.photoPickerService = this.GetService<IPhotoPickerService>();
}
private IObservableCollection<UploadItemViewModel> LoadUploadItems()
{
using (var unitOfWork = UnitOfWork.Start ())
{
return new SimpleObservableCollection<UploadItemViewModel>(uploadItemTasks.GetAll());
}
}
public void StartUpload ()
{
if (this.Uploads == null || this.Uploads.Count == 0) {
ReportError("Error", "No images to upload");
return;
}
this.Uploads.ForEach (uploadItem => PostCallback (uploadItem));
}
private void PostCallback (UploadItemViewModel uploadAsset)
{
IProgressReporter progressReporter = uploadAsset;
this.photoPickerService.GetAssetFullImage(uploadAsset.ImageUrl,
(image) => {
UIImage fullImage = image;
NSData jpeg = fullImage.AsJPEG();
byte[] jpegBytes = new byte[jpeg.Length];
System.Runtime.InteropServices.Marshal.Copy(jpeg.Bytes, jpegBytes, 0, Convert.ToInt32(jpeg.Length));
MemoryStream stream = new MemoryStream(jpegBytes);
Uri destinationUrl = new Uri(uploadAsset.DestinationUrl + "&name=" + uploadAsset.Name + "&contentType=image%2FJPEG");
//TO DO: Move this to plugin
var uploader = new Uploader().UploadPicture (destinationUrl, stream, UploadComplete, progressReporter);
uploader.Host = uploadAsset.Host;
ThreadPool.QueueUserWorkItem (delegate {
uploader.Upload ();
jpeg = null;
});
});
}
private void UploadComplete (string name)
{
if (name == null){
ReportError("Error","There was an error uploading the media.");
} else
{
//ReportError("Succes", name);
}
}
项目 ViewModel 看起来像:
public interface IProgressReporter
{
float Progress { get; set;}
}
public abstract class BaseAssetViewModel: BaseViewModel, IBaseAssetViewModel
{
//... just regular properties
}
public class UploadItemViewModel: BaseAssetViewModel, IProgressReporter
{
public UploadItemViewModel(): base()
{
}
private float progress;
public float Progress {
get {
return this.progress;
}
set {
this.progress = value;
this.RaisePropertyChanged(() => Progress);
}
}
}
项目的视图继承自MvxBindableTableViewCell
并具有以下属性:
private float progress;
public float ProgressMarker {
get {
return progress;
}
set {
progress = value;
// change progressbar or textfield here
}
}
tableviewcellUploadItemViewModel
通过 BindingText 绑定到:
public const string BindingText = @"ProgressMarker Progress, Converter=Float;";
Uploader
片段中提到的类UploadListViewModel
实现了一个私有方法,该方法试图在 IProgressReporter 上设置进度。
float progressValue;
void SetProgress (float newvalue)
{
progressValue = newvalue;
this.dispatcher.InvokeOnMainThread (delegate {
if (ProgressReporter != null)
ProgressReporter.Progress = progressValue;
});
}
在第一次查看列表期间,我可以看到 ViewModel 和 View 中的属性都被命中,但是当我通过接口更新 ViewModel 时,tableviewcellIProgressReporter
中的 View 中的新值Progress
没有更新,也没有调用该属性.
我做错了什么或者我在这里错过了什么?
更新:检查这个问题的答案。