如何在MAUI（WinUI3）项目中替换Acr.UserDialogs？

需求背景 #

将基于UWP的Xamarin项目迁移至MAUI WinUI3，原项目使用Acr.UserDialogs实现进度对话框和提示框，但该组件不支持MAUI，需寻找等效方案，具体需实现：

1. 数据导入期间显示带进度更新的对话框
2. 导入完成/出错时显示提示对话框

原UWP代码参考 #

using Acr.UserDialogs;

public class ImportDataForWin : IImportDataForWin
{
    private IProgressDialog progress;

    public async Task ImportData()
    {
        var picker = new Windows.Storage.Pickers.FileOpenPicker
        {
            ViewMode = Windows.Storage.Pickers.PickerViewMode.Thumbnail,
            SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.PicturesLibrary
        };

        picker.FileTypeFilter.Add(".xlsx");
        picker.FileTypeFilter.Add(".xls");

        var file = await picker.PickSingleFileAsync();

        if (file != null)
        {
            var config = new ProgressDialogConfig()
                .SetTitle("Importing Data")
                .SetIsDeterministic(false);

            progress = UserDialogs.Instance.Progress(config);
            progress.PercentComplete = 0;
            progress.Show();

            // Some code
            var countMax = itemsToAdd.Count();
            var rowCount = 0;
            foreach (var item in itemsToAdd)
            {
                rowCount++;
                await SaveData(item);
                progress.PercentComplete = (rowCount * 100) / countMax;
            }
            progress.Hide();

            UserDialogs.Instance.Alert("errorMessage");
        }
    }
}

MAUI WinUI3实现方案 #

我们可以通过依赖服务+WinUI3原生控件实现需求，既保留WinUI3的原生体验，又符合MAUI的架构规范。

步骤1：定义跨平台服务接口

在MAUI共享项目中定义统一的对话框服务接口：

public interface IProgressDialogService
{
    // 显示进度对话框
    Task ShowProgressDialog(string title, bool isIndeterminate = false);
    // 更新进度百分比
    Task UpdateProgress(int percent);
    // 关闭进度对话框
    Task HideProgressDialog();
    // 显示提示对话框
    Task ShowAlert(string title, string message, string cancelButtonText);
}

步骤2：WinUI3平台实现服务

在MAUI的WinUI项目中实现上述接口，使用WinUI3原生ContentDialog：

using Microsoft.UI.Xaml.Controls;
using Microsoft.Maui.ApplicationModel;
using Microsoft.Maui.Controls;

[assembly: Dependency(typeof(WinUIProgressDialogService))]
namespace YourAppNamespace.WinUI
{
    public class WinUIProgressDialogService : IProgressDialogService
    {
        private ContentDialog _progressDialog;
        private ProgressBar _progressBar;
        private TextBlock _progressText;

        public async Task ShowProgressDialog(string title, bool isIndeterminate = false)
        {
            await MainThread.InvokeOnMainThreadAsync(() =>
            {
                // 创建进度条和文本控件
                _progressBar = new ProgressBar
                {
                    IsIndeterminate = isIndeterminate,
                    Width = 300,
                    Margin = new Microsoft.UI.Xaml.Thickness(0, 10, 0, 10)
                };

                _progressText = new TextBlock
                {
                    Text = "0%",
                    HorizontalAlignment = Microsoft.UI.Xaml.HorizontalAlignment.Center
                };

                // 组装对话框内容
                var contentPanel = new StackPanel();
                contentPanel.Children.Add(_progressBar);
                contentPanel.Children.Add(_progressText);

                // 初始化对话框
                _progressDialog = new ContentDialog
                {
                    Title = title,
                    Content = contentPanel,
                    PrimaryButtonText = "",
                    CloseButtonText = "",
                    IsPrimaryButtonEnabled = false,
                    IsCloseButtonEnabled = false,
                    XamlRoot = Window.Current.Handler.PlatformView.XamlRoot
                };

                // 显示对话框
                _ = _progressDialog.ShowAsync();
            });
        }

        public async Task UpdateProgress(int percent)
        {
            await MainThread.InvokeOnMainThreadAsync(() =>
            {
                if (_progressBar != null && !_progressBar.IsIndeterminate)
                {
                    _progressBar.Value = percent;
                    _progressText.Text = $"{percent}%";
                }
            });
        }

        public async Task HideProgressDialog()
        {
            await MainThread.InvokeOnMainThreadAsync(() =>
            {
                _progressDialog?.Hide();
                _progressDialog = null;
                _progressBar = null;
                _progressText = null;
            });
        }

        public async Task ShowAlert(string title, string message, string cancelButtonText)
        {
            await MainThread.InvokeOnMainThreadAsync(async () =>
            {
                var alertDialog = new ContentDialog
                {
                    Title = title,
                    Content = message,
                    CloseButtonText = cancelButtonText,
                    XamlRoot = Window.Current.Handler.PlatformView.XamlRoot
                };

                await alertDialog.ShowAsync();
            });
        }
    }
}

步骤3：共享项目中使用服务

修改原ImportDataForWin类，注入并使用服务，同时替换文件选择器为MAUI跨平台版本：

using Microsoft.Maui.Storage;

public class ImportDataForWin : IImportDataForWin
{
    private readonly IProgressDialogService _progressDialogService;

    // 通过构造函数注入服务
    public ImportDataForWin(IProgressDialogService progressDialogService)
    {
        _progressDialogService = progressDialogService;
    }

    public async Task ImportData()
    {
        // 使用MAUI跨平台文件选择器
        var excelFileType = new FilePickerFileType(new Dictionary<DevicePlatform, IEnumerable<string>>
        {
            { DevicePlatform.WinUI, new[] { ".xlsx", ".xls" } }
        });

        var fileResult = await FilePicker.Default.PickAsync(new PickOptions
        {
            FileTypes = excelFileType,
            PickerTitle = "Select Excel File"
        });

        if (fileResult != null)
        {
            await _progressDialogService.ShowProgressDialog("Importing Data", isIndeterminate: false);

            try
            {
                // 模拟获取导入数据项
                var itemsToAdd = GetImportItems(fileResult.FullPath);
                var totalCount = itemsToAdd.Count();
                var currentCount = 0;

                foreach (var item in itemsToAdd)
                {
                    currentCount++;
                    await SaveData(item);
                    // 更新进度
                    await _progressDialogService.UpdateProgress((currentCount * 100) / totalCount);
                }

                // 导入成功提示
                await _progressDialogService.ShowAlert("Success", "Data imported successfully!", "OK");
            }
            catch (Exception ex)
            {
                // 错误提示
                await _progressDialogService.ShowAlert("Error", ex.Message, "OK");
            }
            finally
            {
                // 确保关闭进度对话框
                await _progressDialogService.HideProgressDialog();
            }
        }
    }

    // 辅助方法：读取Excel文件获取数据项
    private List<object> GetImportItems(string filePath)
    {
        // 这里替换为实际的Excel读取逻辑
        return new List<object>();
    }

    // 辅助方法：保存单条数据
    private async Task SaveData(object item)
    {
        // 这里替换为实际的数据保存逻辑
        await Task.Delay(100); // 模拟耗时操作
    }
}

关键说明 #

• 文件选择器：使用MAUI内置的FilePicker替代UWP原生控件，实现跨平台兼容，同时针对WinUI3配置特定的文件类型。
• 线程安全：所有UI操作必须通过MainThread.InvokeOnMainThreadAsync执行，避免跨线程访问UI控件的异常。
• 灵活性：通过依赖服务实现平台特定逻辑，后续如需扩展其他平台（如Android、iOS），只需添加对应平台的服务实现即可。

内容的提问来源于stack exchange，提问作者Monal