求助：如何将.NET Maui中DXExpress日历月份绑定到按钮文本

1. 准备ViewModel（核心绑定逻辑） #

创建实现INotifyPropertyChanged的ViewModel，托管同步用的日期属性：

using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows.Input;

public class CalendarViewModel : INotifyPropertyChanged
{
    private DateTime _selectedDate = DateTime.Now;
    public DateTime SelectedDate
    {
        get => _selectedDate;
        set
        {
            if (_selectedDate != value)
            {
                _selectedDate = value;
                OnPropertyChanged();
                // 同步日历显示的月份
                DisplayDate = new DateTime(value.Year, value.Month, 1);
            }
        }
    }

    private DateTime _displayDate = DateTime.Now;
    public DateTime DisplayDate
    {
        get => _displayDate;
        set
        {
            if (_displayDate != value)
            {
                _displayDate = value;
                OnPropertyChanged();
                // 切换月份时同步选中日期到当月第一天
                SelectedDate = new DateTime(value.Year, value.Month, 1);
            }
        }
    }

    public ICommand OpenCalendarPopupCommand { get; }

    public CalendarViewModel()
    {
        OpenCalendarPopupCommand = new Command(async () =>
        {
            var popup = new CalendarPopup();
            popup.BindingContext = this;
            await Application.Current.MainPage.ShowPopupAsync(popup);
        });
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

2. 主页面XAML（绑定按钮文本） #

设置页面绑定上下文，将按钮文本绑定到格式化后的月份：

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:YourNamespace"
             x:Class="YourNamespace.MainPage">
    <ContentPage.BindingContext>
        <local:CalendarViewModel />
    </ContentPage.BindingContext>

    <VerticalStackLayout>
        <Button Text="{Binding SelectedDate, StringFormat='{0:MMMM yyyy}'}"
                Command="{Binding OpenCalendarPopupCommand}" />
    </VerticalStackLayout>
</ContentPage>

3. 弹窗XAML（绑定DXExpress日历） #

创建弹窗页面，将DxCalendar的关键属性双向绑定到ViewModel：

<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:dxc="clr-namespace:DevExpress.Maui.Editors;assembly=DevExpress.Maui.Editors"
             x:Class="YourNamespace.CalendarPopup">
    <VerticalStackLayout>
        <dxc:DxCalendar SelectedDate="{Binding SelectedDate, Mode=TwoWay}"
                        DisplayDate="{Binding DisplayDate, Mode=TwoWay}"
                        SelectionMode="Single" />
        <Button Text="确定" Clicked="OnConfirmClicked" />
    </VerticalStackLayout>
</ContentView>

4. 弹窗后台代码（关闭逻辑） #

处理弹窗确定按钮的关闭操作：

private void OnConfirmClicked(object sender, EventArgs e)
{
    ((Popup)Parent).Close();
}

关键逻辑说明 #

• 通过双向绑定让日历的DisplayDate（显示月份）和SelectedDate与ViewModel同步，按钮文本通过StringFormat直接渲染月份名称。
• 用户切换日历月份时，DisplayDate的变更会触发ViewModel属性更新，进而同步SelectedDate，最终自动刷新按钮文本。
• 弹窗绑定上下文直接复用主页面ViewModel实例，避免因对象不一致导致绑定失效。

内容的提问来源于stack exchange，提问作者Fernando