Guides----https://developer.xamarin.com/guides/xamarin-forms/user-interface/picker/
API-----https://developer.xamarin.com/api/type/Xamarin.Forms.Picker/
Demo: Picker省,市,区 三级联动
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
public class District //区
{
public string DistrictName { get; set; } //区名字
public string DistrictPostcode { get; set; } //区的邮编
}
public class City
{
public ObservableCollection<District> DistrictObservableCollection { get; set; } //区的集合
public string CityName { get; set; } //城市的名字
}
public class Province
{
public ObservableCollection<City> CityObservableCollection { get; set; } //城市的集合
public string ProvinceName { get; set; } //省份的名字
}
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
public static class Data
{
public static ObservableCollection<Province> Provinces { get; private set; }
static Data()
{
Provinces = new ObservableCollection<Province>()
{
new Province()
{
ProvinceName = "福建省",
CityObservableCollection = new ObservableCollection<City>()
{
new City()
{
CityName = "福州市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "鼓楼区",
DistrictPostcode = "350001"
},
new District()
{
DistrictName = "晋安区",
DistrictPostcode = "350002"
},
new District()
{
DistrictName = "台江区",
DistrictPostcode = "350003"
},
new District()
{
DistrictName = "仓山区",
DistrictPostcode = "350004"
},
}
},
new City()
{
CityName = "厦门市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "思明区",
DistrictPostcode = "361001"
},
new District()
{
DistrictName = "湖里区",
DistrictPostcode = "361002"
},
new District()
{
DistrictName = "集美区",
DistrictPostcode = "361003"
},
new District()
{
DistrictName = "海沧区",
DistrictPostcode = "361004"
},
new District()
{
DistrictName = "翔安区",
DistrictPostcode = "361005"
},
}
},
new City()
{
CityName = "泉州市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "丰泽区",
DistrictPostcode = "362001"
},
new District()
{
DistrictName = "鲤城区",
DistrictPostcode = "362002"
},
new District()
{
DistrictName = "洛江区",
DistrictPostcode = "362003"
},
new District()
{
DistrictName = "泉港区",
DistrictPostcode = "362004"
},
}
},
}
},
new Province()
{
ProvinceName = "浙江省",
CityObservableCollection = new ObservableCollection<City>()
{
new City()
{
CityName = "杭州市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "西湖区",
DistrictPostcode = "310001"
},
new District()
{
DistrictName = "余杭区",
DistrictPostcode = "310002"
},
new District()
{
DistrictName = "萧山区",
DistrictPostcode = "310003"
},
new District()
{
DistrictName = "下城区",
DistrictPostcode = "310004"
},
}
},
new City()
{
CityName = "宁波市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "海曙区",
DistrictPostcode = "315001"
},
new District()
{
DistrictName = "江东区",
DistrictPostcode = "315002"
},
new District()
{
DistrictName = "江北区",
DistrictPostcode = "315003"
},
new District()
{
DistrictName = "镇海区",
DistrictPostcode = "315004"
},
new District()
{
DistrictName = "北仑区",
DistrictPostcode = "315005"
},
}
},
new City()
{
CityName = "温州市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "鹿城区",
DistrictPostcode = "325001"
},
new District()
{
DistrictName = "龙湾区",
DistrictPostcode = "325002"
},
new District()
{
DistrictName = "瓯海区",
DistrictPostcode = "325003"
},
}
},
}
},
new Province()
{
ProvinceName = "安徽省",
CityObservableCollection = new ObservableCollection<City>()
{
new City()
{
CityName = "合肥市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "蜀山区",
DistrictPostcode = "230001"
},
new District()
{
DistrictName = "庐阳区",
DistrictPostcode = "230002"
},
new District()
{
DistrictName = "瑶海区",
DistrictPostcode = "230003"
},
new District()
{
DistrictName = "包河区",
DistrictPostcode = "230004"
},
}
},
new City()
{
CityName = "淮北市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "相山区",
DistrictPostcode = "235001"
},
new District()
{
DistrictName = "杜集区",
DistrictPostcode = "235002"
},
new District()
{
DistrictName = "烈山区",
DistrictPostcode = "235003"
},
}
},
new City()
{
CityName = "宿州市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "埇桥区",
DistrictPostcode = "234001"
},
}
},
}
},
new Province()
{
ProvinceName = "江西省",
CityObservableCollection = new ObservableCollection<City>()
{
new City()
{
CityName = "南昌市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "东湖区",
DistrictPostcode = "330001"
},
new District()
{
DistrictName = "西湖区",
DistrictPostcode = "330002"
},
new District()
{
DistrictName = "青云谱区",
DistrictPostcode = "330003"
},
new District()
{
DistrictName = "湾里区",
DistrictPostcode = "330004"
},
}
},
new City()
{
CityName = "景德镇市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "珠山区",
DistrictPostcode = "333001"
},
new District()
{
DistrictName = "昌江区",
DistrictPostcode = "333002"
},
}
},
new City()
{
CityName = "九江市",
DistrictObservableCollection = new ObservableCollection<District>()
{
new District()
{
DistrictName = "浔阳区",
DistrictPostcode = "332001"
},
new District()
{
DistrictName = "庐山区",
DistrictPostcode = "332002"
},
}
},
}
}
};
}
}
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="DemoTest_3_28.PickerDemo.PickerDemoPage">
<StackLayout Orientation="Vertical"
VerticalOptions="Center"
HorizontalOptions="Center">
<Label Text="邮编:"
HorizontalOptions="Center"
FontAttributes="Bold"
FontSize="20"
x:Name="label_Postcode" />
<StackLayout Orientation="Horizontal">
<Picker x:Name="provincePicker" Title="省份" SelectedIndexChanged="ProvincePicker_OnSelectedIndexChanged"/>
<Picker x:Name="CityPicker" Title="城市" SelectedIndexChanged="CityPicker_OnSelectedIndexChanged"/>
<Picker x:Name="DistrictPicker" Title="区" SelectedIndexChanged="DistrictPicker_OnSelectedIndexChanged"/>
</StackLayout>
</StackLayout>
</ContentPage>
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DemoTest_3_28.Models;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace DemoTest_3_28.PickerDemo
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class PickerDemoPage : ContentPage
{
private ObservableCollection<Province> source;
private string postcode = null;
public PickerDemoPage()
{
InitializeComponent();
source = Data.Provinces;
foreach (var province in source)
{
provincePicker.Items.Add(province.ProvinceName);
}
provincePicker.SelectedIndex = 0;
}
private void ProvincePicker_OnSelectedIndexChanged(object sender, EventArgs e)
{
if (provincePicker.SelectedIndex!=-1)
{
var result_1 = source[provincePicker.SelectedIndex].CityObservableCollection;
CityPicker.Items.Clear();//重要, 而且触发CityPicker_OnSelectedIndexChanged,CityPicker.SelectedIndex=-1
foreach (var city in result_1)
{
CityPicker.Items.Add(city.CityName);
}
CityPicker.SelectedIndex = 0;
}
}
private void CityPicker_OnSelectedIndexChanged(object sender, EventArgs e)
{
if (CityPicker.SelectedIndex!=-1)
{
var result_2 = source[provincePicker.SelectedIndex].CityObservableCollection[CityPicker.SelectedIndex].DistrictObservableCollection;
DistrictPicker.Items.Clear(); //重要
foreach (var district in result_2)
{
DistrictPicker.Items.Add(district.DistrictName);
}
DistrictPicker.SelectedIndex = 0; //重要
}
}
private void DistrictPicker_OnSelectedIndexChanged(object sender, EventArgs e)
{
if (DistrictPicker.SelectedIndex!=-1)
{
postcode = source[provincePicker.SelectedIndex].CityObservableCollection[CityPicker.SelectedIndex].DistrictObservableCollection[DistrictPicker.SelectedIndex].DistrictPostcode;
label_Postcode.Text = "邮编:" + postcode;
}
}
}
}
时间： 2024-12-15 23:33:58