Question

为ProgressBar做动画时遇到问题。

我的目标是，每次处理ProgressBar.Value和CopyAsync 时，我都希望CreateFolderAsync更新。

我的xaml文件中有4个组件，每次完成该过程（CopyAsync和CreateFolderAsync）时都会更新，TextBlock运行正常，每次都会更新过程完成。问题在于ProgressBar它将在所有过程结束时更新UI。

我正在使用Dispatcher.RunAsync，以及我放入TextBlock和ProgressBar的更新过程。

请告知，如何更新以下代码的ProgressBar。

MainPage.xaml中

<TextBlock Text="Files:" FontSize="72" Margin="363,270,834,402"></TextBlock>
<TextBlock Text="Folders:" FontSize="72" Margin="273,411,834,270"></TextBlock>
<TextBlock x:Name="Files" FontSize="72" Margin="582,270,609,402"></TextBlock>
<TextBlock x:Name="Folders" FontSize="72" Margin="582,411,588,270"></TextBlock>
<ProgressBar x:Name="FolderBar" Height="25" Margin="10,532,-10,211"></ProgressBar>
<ProgressBar x:Name="FileBar" Height="25" Margin="10,565,-10,178"></ProgressBar>

MainPage.xaml.cs中

private async void CopyFolder(string path)
{
    IStorageFolder destination = ApplicationData.Current.LocalFolder;
    IStorageFolder root = Package.Current.InstalledLocation;

    if (path.Equals(ROOT) && !await FolderExistAsync(ROOT))
        await destination.CreateFolderAsync(ROOT);

    destination = await destination.GetFolderAsync(path);
    root = await root.GetFolderAsync(path);

    IReadOnlyList<IStorageItem> items = await root.GetItemsAsync();

    // For count the total files
    if (path.Equals(ROOT))
        TotalFiles(path);

    foreach (IStorageItem item in items)
    {
        if (item.GetType() == typeof(StorageFile))
        {
            IStorageFile presFile = await StorageFile.GetFileFromApplicationUriAsync(
                new Uri("ms-appx:///" + path.Replace("\\", "/") + "/" + item.Name));

            if (!await FileExistAsync(path, item.Name))
            {
                IStorageFile copyFile = await presFile.CopyAsync(destination);
                countFiles++;

                if (copyFile != null)
                {
                    await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
                        () =>
                        {
                            // The update for TextBlock is fine
                            Files.Text = countFiles.ToString();
                            // But for the ProgressBar it will update in the end of process
                            FileBar.Value = countFiles / totalFiles * 100;
                        });
                }

            }
        }
        else
        {
            if (!await FolderExistAsync(path + "\\" + item.Name))
            {
                StorageFolder createFolder = await destination.CreateFolderAsync(item.Name);
                countFolders++;

                if (createFolder != null)
                {
                    await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
                        () =>
                        {
                            // The update for TextBlock is fine
                            Folders.Text = countFolders.ToString();
                            // But for the ProgressBar it will update in the end of process
                            FolderBar.Value = countFolders / totalFolders * 100;
                        });
                }

            }

            CopyFolder(path + "\\" + item.Name);
        }
    }

}

Answer 1

countFiles和totalFiles都是整数，所以当你将一个除以另一个时，它会执行整数除法;由于totalFiles始终大于或等于countFiles，因此结果始终为0，除非它在1的末尾。

要解决此问题，您需要在划分之前强制转换为double，以便执行浮点除法：

FileBar.Value = (double)countFiles / totalFiles * 100;

WinRT - 更新进度条

1 个答案: