我已经在xaml.cs文件中对代码背后的逻辑进行了编码，现在我想将代码从代码背后转移到ViewModel。除了代码重构之外，怎么能做到这一点呢。
我是xamarin 的新手
这是背后的代码
namespace _somename
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class CareingtonFeeSchedule : ContentPage
{
private OneDentalFeeScheduleService oneDentalFeeScheduleService;
private ObservableCollection<ProviderSearchViewModel> _allGroups;
private ObservableCollection<ProviderSearchViewModel> _expandedGroups;
protected ObservableCollection<Grouping<string, FeeScheduleItem>> feeScheduleGroups;
protected ObservableCollection<FeeScheduleItem> feeScheduleItems;
private readonly AppViewModel AppViewModelInstance;
private Plugin.Geolocator.Abstractions.Position currentPosition;
private FeeScheduleModel feeScheduleDataResult;
public CareingtonFeeSchedule(AppViewModel appViewModel)
{
InitializeComponent();
AppViewModelInstance = appViewModel;
BindingContext = AppViewModelInstance;
AppViewModelInstance.IsActivityLoading = true;
LoadFeeeSchedule();
}
private void HeaderTapped(object sender, EventArgs args)
{
int selectedIndex = _expandedGroups.IndexOf(
((ProviderSearchViewModel)((Button)sender).CommandParameter));
_allGroups[selectedIndex].Expanded = !_allGroups[selectedIndex].Expanded;
UpdateListContent();
}
async Task OnHomeFeeScheduleTapped_TappedAsync(object sender, EventArgs args)
{
await Navigation.PushAsync(new AccLandPage(AppViewModelInstance));
}
private void ProviderBar_TextChanged(object sender, TextChangedEventArgs e)
{
var keyword = ProviderSearchBar.Text;
GroupedView.ItemsSource =
_expandedGroups.Where(s =>
s.Title.ToLower().Contains(keyword.ToLower()));
}
private void UpdateListContent()
{
_expandedGroups = new ObservableCollection<ProviderSearchViewModel>();
foreach (ProviderSearchViewModel group in _allGroups)
{
ProviderSearchViewModel newGroup = new ProviderSearchViewModel(group.Title, group.ShortName, group.Expanded);
if (group.Expanded)
{
foreach (Plan plan in group)
{
newGroup.Add(plan);
}
}
_expandedGroups.Add(newGroup);
}
GroupedView.ItemsSource = _expandedGroups;
}
public FeeScheduleModel FeeScheduleDataResult
{
protected set
{
feeScheduleDataResult = value;
OnPropertyChanged(nameof(FeeScheduleDataResult));
}
get => feeScheduleDataResult;
}
protected int feeScheduleCount;
public int FeeScheduleCount => feeScheduleCount;
private async Task<bool> LoadFeeeSchedule()
{
try
{
if (oneDentalFeeScheduleService == null)
{
oneDentalFeeScheduleService = new OneDentalFeeScheduleService("1dental.com");
}
var feeSchedRes = await oneDentalFeeScheduleService.GetFeeScheduleAsync(AppViewModelInstance.ZipCode, string.Empty, CancellationToken.None);
if (feeSchedRes?.Schedule?.Count > 0)
{
ConvertFeeScheuleDict(feeSchedRes.Schedule);
}
else FeeScheduleDataResult = null;
return true;
}
catch (Exception eX)
{
with the fee schedule lookup: n{eX.Message}", "OK");
return false;
}
finally
{
AppViewModelInstance.IsActivityLoading = false;
actInd.IsRunning = false;
}
}
private void ConvertFeeScheuleDict(Dictionary<string, List<FeeScheduleItem>> feesche)
{
ObservableCollection<ProviderSearchViewModel> list = new ObservableCollection<ProviderSearchViewModel>();
ProviderSearchViewModel psm = null;
foreach (var item in feesche)
{
psm = new ProviderSearchViewModel(item.Key, "");
foreach (var valitem in item.Value)
{
Plan p = new Plan();
p.Code = valitem.Code;
p.CostDisplay = valitem.CostDisplay;
p.Description = valitem.ProcedureSecondary;
p.Name = valitem.Procedure;
psm.Add(p);
}
list.Add(psm);
}
_allGroups = list;
UpdateListContent();
}
private async void GetZipCode()
{
try
{
if (AppViewModelInstance.UserPosition == null)
{
try
{
var hasPermission = await Utils.CheckPermissions(Permission.Location);
if (!hasPermission)
{
await Navigation.PushAsync(new MainScreen());
return;
}
}
catch (Exception ex)
{
Debug.WriteLine($"Exception occurred while looking permission during Appearing event: {ex}");
}
var locator = CrossGeolocator.Current;
currentPosition = await locator.GetPositionAsync(new TimeSpan(0, 0, 0, 10, 0));
var addressList = await locator.GetAddressesForPositionAsync(currentPosition, null);
AppViewModelInstance.UserPosition = currentPosition;
foreach (var item in addressList)
{
AppViewModelInstance.ZipCode = item.PostalCode;
ZipCodeEntry.Text = item.PostalCode;
break;
}
}
else
{
var locator = CrossGeolocator.Current;
currentPosition = AppViewModelInstance.UserPosition;
var addressList = await locator.GetAddressesForPositionAsync(currentPosition, null);
foreach (var item in addressList)
{
AppViewModelInstance.ZipCode = item.PostalCode;
ZipCodeEntry.Text = item.PostalCode;
break;
}
}
LoadFeeeSchedule();
}
catch (Exception ex)
{
Debug.WriteLine($"Exception occurred while looking up location during Appearing event: {ex}");
}
}
private void ZipCodeEntry_Complete(object sender, EventArgs e)
{
if (sender != null)
{
AppViewModelInstance.ZipCode = ((Entry)sender).Text;
}
}
private void ZipCodeEntry_Changed(object sender, EventArgs e)
{
if (sender != null)
{
string _text = ((Entry)sender).Text; //Get Current Text
if (_text.Length > 5) //If it is more than your character restriction
{
_text = _text.Remove(_text.Length - 1); // Remove Last character
ZipCodeEntry.Text = _text; //Set the Old value
}
if (_text.Length == 5)
{
AppViewModelInstance.ZipCode = _text;
LoadFeeeSchedule();
}
}
}
public bool CanRefreshExecute(string tempVal = null)
{
if (AppViewModelInstance.IsRefreshing) return false;
var valToCheck = tempVal ?? AppViewModelInstance.ZipCode;
if (string.IsNullOrEmpty(valToCheck) || string.IsNullOrWhiteSpace(valToCheck)) return false;
bool isDigitString = true;
foreach (var c in valToCheck)
{
if (char.IsDigit(c)) continue;
isDigitString = false;
}
if (isDigitString) AppViewModelInstance.ZipCode = valToCheck;
return isDigitString;
}
private void GroupedView_ItemTapped(object sender, ItemTappedEventArgs e)
{
}
}
}
只需将代码导出到视图模型，并将视图模型设置为页面的绑定上下文。例如在构造函数中：
//In the code behind
PageViewModel viewModel;
public Page()
{
this.BindingContext = viewModel = new PageViewModel();
//...
}
ViewModel应实现INotifyPropertyChanged。
(由事件触发的函数必须留在代码后面，并通过ViewModel属性访问视图模型(