c# - Xamarin 表单选择器级联

Question

我参与了一个项目，我遇到了以下情况:我有一个选择器(下拉菜单)，它需要根据第一个选择器(级联)中的第一个选定项目显示第二个选择器。值是动态的(来自 Sqlite 表)。这里有我的代码:

XAML

 Picker 1
    <Picker x:Name="picker" Title="Select Country" SelectedIndexChanged="OnModeChosen">
    Picker 2
    <Picker x:Name="picker2" Title="Select Regions" IsEnabled="False">

模型

public class Country
        {
          [PrimaryKey]
          Public int CountryId {get;set;}
          public string CountryName {get;set;}

          public Country(){}
        }

        public class Regions
        {
          [PrimaryKey]
          public int RegionsId {get; set;}
          public string RegionsName {get;set;}
          [ForeignKey(typeof(Country))]
          public int CountryId {get;set;}

          public Regions(){}
        }

//代码隐藏

private void OnModeChosen(object sender, EventArgs e)
    {
    Picker modePicker = (Picker)sender;
    var mode = picker.SelectedIndex;
    picker2.Items.Clear();

         switch(mode)
         {
           //This is the part I would like dynamic
         }
     }

我希望处理程序“OnModeChosen”动态工作(从选择器 1 中选择的任何值将显示选择器 2 的相应值)。顺便说一句，我会很感激任何其他方法，因为我有兴趣获得预期的结果。感谢你们的支持。我为此工作了几个小时，但在互联网上找不到任何值得的东西。

Answer 1

所以这就是我在项目中解决它的方法:

  private void OnModeChosen(object sender, EventArgs e)
    {
         Country country = ((Country)(picker.SelectedItem)) // get the country object from  the picker
          picker2.ItemsSource =  GetRegions(country.CountryId ) // call the function to get the regions for that country
          picker2.ItemDisplayBinding = New Binding("RegionsName")
          picker2.SelectedIndex = 0 // not sure why I did this, I think to make sure an item was selected
        stackpicker2.IsVisible = true // make the stack layout visible with the 2nd picker
        picker2.IsEnabled = true;
    }

希望对你有帮助