Question

我有这个任务，它用数据表中的数据填充了一个可观察的集合。

问题是，当我运行此界面时，UI在以下位置冻结1秒：

Map.Add(mapCollection);

我尝试没有成功

Task.Run

整个代码是这样的：

private async Task<ObservableCollection<ShiftPageListItemViewModel>> GetMapAsync()
{
    mDbConnect = new DBConnect();

    var ShiftsTab = new DataTable();

    ShiftsTab = await mDbConnect.MapAsync(Date.ToString("yyyy-MM-dd"));

    var Map = new ObservableCollection<ShiftPageListItemViewModel>();


    foreach (DataRow row in ShiftsTab.Rows)
    {
        var mapCollection = new ShiftPageListItemViewModel
        {
            BorderTag = row[0].ToString(),
            Name = row[1].ToString(),
            HourTitle = ShiftsTab.Rows.IndexOf(row) < 10 ? $"Ora0{ShiftsTab.Rows.IndexOf(row)}" : $"Ora{ShiftsTab.Rows.IndexOf(row)}",
            Ora00 = Convert.ToDouble(row[2].ToString()),
            Ora01 = Convert.ToDouble(row[3].ToString()),
            Ora02 = Convert.ToDouble(row[4].ToString()),
            Ora03 = Convert.ToDouble(row[5].ToString()),
            Ora04 = Convert.ToDouble(row[6].ToString()),
            Ora05 = Convert.ToDouble(row[7].ToString()),
            Ora06 = Convert.ToDouble(row[8].ToString()),
            Ora07 = Convert.ToDouble(row[9].ToString()),
            Ora08 = Convert.ToDouble(row[10].ToString()),
            Ora09 = Convert.ToDouble(row[11].ToString()),
            Ora10 = Convert.ToDouble(row[12].ToString()),
            Ora11 = Convert.ToDouble(row[13].ToString()),
            Ora12 = Convert.ToDouble(row[14].ToString()),
            Ora13 = Convert.ToDouble(row[15].ToString()),
            Ora14 = Convert.ToDouble(row[16].ToString()),
            Ora15 = Convert.ToDouble(row[17].ToString()),
            Ora16 = Convert.ToDouble(row[18].ToString()),
            Ora17 = Convert.ToDouble(row[19].ToString()),
            Ora18 = Convert.ToDouble(row[20].ToString()),
            Ora19 = Convert.ToDouble(row[21].ToString()),
            Ora20 = Convert.ToDouble(row[22].ToString()),
            Ora21 = Convert.ToDouble(row[23].ToString()),
            Ora22 = Convert.ToDouble(row[24].ToString()),
            Ora23 = Convert.ToDouble(row[25].ToString()),
        };

            Map.Add(mapCollection);

    }; 
    return Map;
}

任何人都可以帮助我，我只想在不冻结用户界面的情况下运行它

Answer 1

您是说Task.Run对您不起作用。也许您忘记了await关键字？

将您计算量大的代码包装到await Task.Run(() => {...});中，如下所示：

private async Task<ObservableCollection<ShiftPageListItemViewModel>> GetMapAsync()
{
    mDbConnect = new DBConnect();

    var ShiftsTab = new DataTable();

    ShiftsTab = await mDbConnect.MapAsync(Date.ToString("yyyy-MM-dd"));

    var Map = new ObservableCollection<ShiftPageListItemViewModel>();

    await Task.Run(() =>
    {
        foreach (DataRow row in ShiftsTab.Rows)
        {
            var mapCollection = new ShiftPageListItemViewModel
            {
                BorderTag = row[0].ToString(),
                Name = row[1].ToString(),
                HourTitle = ShiftsTab.Rows.IndexOf(row) < 10 ? $"Ora0{ShiftsTab.Rows.IndexOf(row)}" : $"Ora{ShiftsTab.Rows.IndexOf(row)}",
                Ora00 = Convert.ToDouble(row[2].ToString()),
                Ora01 = Convert.ToDouble(row[3].ToString()),
                Ora02 = Convert.ToDouble(row[4].ToString()),
                Ora03 = Convert.ToDouble(row[5].ToString()),
                Ora04 = Convert.ToDouble(row[6].ToString()),
                Ora05 = Convert.ToDouble(row[7].ToString()),
                Ora06 = Convert.ToDouble(row[8].ToString()),
                Ora07 = Convert.ToDouble(row[9].ToString()),
                Ora08 = Convert.ToDouble(row[10].ToString()),
                Ora09 = Convert.ToDouble(row[11].ToString()),
                Ora10 = Convert.ToDouble(row[12].ToString()),
                Ora11 = Convert.ToDouble(row[13].ToString()),
                Ora12 = Convert.ToDouble(row[14].ToString()),
                Ora13 = Convert.ToDouble(row[15].ToString()),
                Ora14 = Convert.ToDouble(row[16].ToString()),
                Ora15 = Convert.ToDouble(row[17].ToString()),
                Ora16 = Convert.ToDouble(row[18].ToString()),
                Ora17 = Convert.ToDouble(row[19].ToString()),
                Ora18 = Convert.ToDouble(row[20].ToString()),
                Ora19 = Convert.ToDouble(row[21].ToString()),
                Ora20 = Convert.ToDouble(row[22].ToString()),
                Ora21 = Convert.ToDouble(row[23].ToString()),
                Ora22 = Convert.ToDouble(row[24].ToString()),
                Ora23 = Convert.ToDouble(row[25].ToString()),
            };

            Map.Add(mapCollection);
        };

    }); 
    return Map;
}

Foreach循环冻结ui C＃

1 个答案: