如何获取多请求表单下所有动态生成DatePicker的选中日期值

1 调整数据存储结构 #

放弃原有的全局单字典存储逻辑，改为嵌套结构，每个请求表单独立维护自身的日期选择器集合，避免不同表单的序号、控件冲突：

// 单个表单的日期选择器存储类
public class FormDateInfo
{
    // 当前表单已添加的日期组序号，每个表单独立计数
    public int CurrentDatePairIndex { get; set; } = 1;
    // 键为日期组序号，值为对应开始日期选择器
    public Dictionary<int, DatePicker> StartDatePickers { get; set; } = new();
    // 键为日期组序号，值为对应结束日期选择器
    public Dictionary<int, DatePicker> EndDatePickers { get; set; } = new();
}

// 全局存储所有请求表单的日期数据，键可以是表单的唯一ID、也可以直接用表单的控件实例作为标识
public Dictionary<object, FormDateInfo> AllRequestFormDates { get; set; } = new();

2 修改日期组添加逻辑 #

点击添加按钮时，首先获取当前按钮所属的请求表单标识，再将生成的DatePicker存入对应表单的存储集合中：

private void AddDateBtn_Clicked(object sender, EventArgs e)
{
    // 获取当前按钮所属的请求表单标识，这里以按钮的Parent（即表单实例）为例，可根据你的实际布局调整取值逻辑
    var currentForm = (sender as Button).Parent;
    // 如果当前表单还没有注册到全局存储，先初始化
    if (!AllRequestFormDates.ContainsKey(currentForm))
    {
        AllRequestFormDates.Add(currentForm, new FormDateInfo());
    }
    var currentFormDateInfo = AllRequestFormDates[currentForm];
    var currentIndex = currentFormDateInfo.CurrentDatePairIndex;

    Grid grid1 = new Grid
    {
        ColumnDefinitions =
        {
            new ColumnDefinition{ Width = new GridLength(0.4, GridUnitType.Star)},
            new ColumnDefinition{ Width = new GridLength(0.6, GridUnitType.Star)}
        }
    };
    Label label1 = new Label
    {
        Text = "Start Date",
        HorizontalOptions = LayoutOptions.StartAndExpand,
        VerticalOptions = LayoutOptions.CenterAndExpand,
        FontSize = Device.GetNamedSize(NamedSize.Caption, typeof(Label)),
        TextColor = Color.Black
    };
    grid1.Children.Add(label1, 0, 0);
    DatePicker startdatePicker1 = new DatePicker
    {
        HorizontalOptions = LayoutOptions.StartAndExpand,
        VerticalOptions = LayoutOptions.CenterAndExpand,
        FontSize = Device.GetNamedSize(NamedSize.Caption, typeof(Label)),
        TextColor = Color.Black
    };
    // 存入当前表单的开始日期集合
    currentFormDateInfo.StartDatePickers.Add(currentIndex, startdatePicker1);
    grid1.Children.Add(startdatePicker1, 1, 0);
    BoxView boxView = new BoxView
    {
        HorizontalOptions = LayoutOptions.FillAndExpand,
        HeightRequest = 1,
        BackgroundColor = Color.LightGray
    };
    // 这里的NewDurationStack也要替换为当前表单对应的日期容器，可从currentForm的子控件中获取
    var currentFormDurationStack = currentForm.FindByName<StackLayout>("NewDurationStack");
    currentFormDurationStack.Children.Add(grid1);
    currentFormDurationStack.Children.Add(boxView);

    Grid grid2 = new Grid
    {
        ColumnDefinitions =
        {
            new ColumnDefinition{ Width = new GridLength(0.4, GridUnitType.Star)},
            new ColumnDefinition{ Width = new GridLength(0.6, GridUnitType.Star)}
        }
    };
    Label label2 = new Label
    {
        Text = "End Date",
        HorizontalOptions = LayoutOptions.StartAndExpand,
        VerticalOptions = LayoutOptions.CenterAndExpand,
        FontSize = Device.GetNamedSize(NamedSize.Caption, typeof(Label)),
        TextColor = Color.Black
    };
    grid2.Children.Add(label2, 0, 0);
    DatePicker enddatePicker1 = new DatePicker
    {
        HorizontalOptions = LayoutOptions.StartAndExpand,
        VerticalOptions = LayoutOptions.CenterAndExpand,
        FontSize = Device.GetNamedSize(NamedSize.Caption, typeof(Label)),
        TextColor = Color.Black
    };
    grid2.Children.Add(enddatePicker1, 1, 0);
    // 存入当前表单的结束日期集合
    currentFormDateInfo.EndDatePickers.Add(currentIndex, enddatePicker1);

    BoxView boxView1 = new BoxView
    {
        HorizontalOptions = LayoutOptions.FillAndExpand,
        HeightRequest = 1,
        BackgroundColor = Color.LightGray
    };
    currentFormDurationStack.Children.Add(grid2);
    currentFormDurationStack.Children.Add(boxView1);

    // 当前表单的日期序号自增
    currentFormDateInfo.CurrentDatePairIndex++;
}

3 批量获取所有日期值 #

遍历全局存储集合即可拿到所有表单的所有选中日期：

// 定义返回结果结构，可根据你的业务需求调整
public class FormDateResult
{
    public object FormId { get; set; }
    public List<(DateTime StartDate, DateTime EndDate)> DateRanges { get; set; } = new();
}

public List<FormDateResult> GetAllFormSelectedDates()
{
    var result = new List<FormDateResult>();
    foreach (var formItem in AllRequestFormDates)
    {
        var formResult = new FormDateResult
        {
            FormId = formItem.Key
        };
        var startPickers = formItem.Value.StartDatePickers;
        var endPickers = formItem.Value.EndDatePickers;
        // 按序号配对日期
        foreach (var index in startPickers.Keys)
        {
            if (endPickers.TryGetValue(index, out var endPicker))
            {
                formResult.DateRanges.Add((startPickers[index].Date, endPicker.Date));
            }
        }
        result.Add(formResult);
    }
    return result;
}

可选优化方案：如果不需要保留控件引用，也可以直接在DatePicker的DateSelected事件中同步更新对应存储的日期值，后续无需遍历控件直接读取预存的日期值即可，性能更好。

内容的提问来源于stack exchange，提问作者Abubakar Hanif