Question

我使用MVVM和Caliburn.Micro，我遇到了问题。所以我在视图中有2个组合框。首先是代表国家名单和第二个城市名单。我希望每当第一个列表中的国家/地区更改时，都会更新城市列表，并显示相应的城市列表。我的问题是城市名单没有更新。这是我的代码：

public class MyViewModel : PropertyChangedBase
{
    Company company = new Company();
    List<string> countries = new List<string> {"USA","Germany" };
    public string Name
    {
        get { return company.name; }
        set { company.name = value;
        }
    }
    public List<string> Countries
    {
        get { return countries; }
        set {
            company.country = ToString();
            NotifyOfPropertyChange(() => Countries);
            NotifyOfPropertyChange(() => Cities);
        }
    }
    public List<string> Cities
    {
        get {
            switch (company.country)
            {
                case "USA": return new List<string> { "New York", "Los Angeles" };  
                case "Germany": return new List<string> { "Hamburg", "Berlin" };
                default: return new List<string> { "DEFAULT", "DEFAULT" };

            }
            }
        set { company.city = value.ToString();
            NotifyOfPropertyChange(() => Cities);
        }
    }

}

现在城市列表仍保留默认成员（DEFAULT，DEFAULT）。该视图仅包含2个具有相应名称的组合框：

<Grid>
        <ComboBox x:Name="Countries" />
        <ComboBox x:Name="Cities" />
</Grid>

一些建议？抱歉我的英语不好。

Answer 1

将国家/地区SelectedItem的{{1}}属性绑定到视图模型的源属性：

ComboBox

...并在此设置器中为<ComboBox x:Name="Countries" ItemsSource="{Binding Countries}" SelectedItem="{Binding SelectedCountry}" /> <ComboBox x:Name="Cities" ItemsSource="{Binding Cities}" />属性引发PropertyChanged事件：

Cities

有关完整示例的详细信息，请参阅以下博客文章，以及有关如何实现此类级联的更多信息public class MyViewModel : PropertyChangedBase { Company company = new Company(); List<string> countries = new List<string> { "USA", "Germany" }; public string SelectedCountry { get { return company.country; } set { company.country = value; NotifyOfPropertyChange(() => SelectedCountry); NotifyOfPropertyChange(() => Cities); } } public List<string> Countries { get { return countries; } set { countries = value; NotifyOfPropertyChange(() => Countries); NotifyOfPropertyChange(() => Cities); } } public List<string> Cities { get { switch (company.country) { case "USA": return new List<string> { "New York", "Los Angeles" }; case "Germany": return new List<string> { "Hamburg", "Berlin" }; default: return new List<string> { "DEFAULT", "DEFAULT" }; } } } }：https://blog.magnusmontin.net/2013/06/17/cascading-comboboxes-in-wpf-using-mvvm/

MVVM Caliburn.micro组合框架Country-City无法正常工作

1 个答案: