HY
我想在一个带有MVVM-Light的Xamarin PCL项目中分享我的自定义xamarin.forms控件的方法。你觉得怎么样?
自定义控制 - > PersonPanel.xaml:
<?xml version="1.0" encoding="utf-8" ?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="xxx.PersonPanel">
<StackLayout Orientation="Vertical">
<Label x:Name="titleLabel" Text="{Binding TitleLabel}"/>
<Entry x:Name="filterText" Placeholder="{Binding FilterPlaceholderText}" Text="{Binding Filter.Lookup}" TextChanged="OnFilterTextChanged"/>
<Label x:Name="resultText" Text="{Binding ResultText}" IsVisible="{Binding ResultTextVisible}"/>
</StackLayout>
</ContentView>
Code-Behind - &gt; PersonPanel.xaml.cs:
public partial class PersonPanel : ContentView
{
public PersonPanel()
{
InitializeComponent();
//Init ViewModel
BindingContext = ServiceLocator.Current.GetInstance<PersonPanelViewModel>();
}
private PersonPanelViewModel PersonPanelViewModel
{
get
{
return (PersonPanelViewModel)BindingContext;
}
}
public string TitleLabel
{
get
{
return PersonPanelViewModel.TitleLabel;
}
set
{
PersonPanelViewModel.TitleLabel = value;
}
}
public string FilterPlaceholderText
{
get
{
return PersonPanelViewModel.FilterPlaceholderText;
}
set
{
PersonPanelViewModel.FilterPlaceholderText = value;
}
}
private void OnFilterTextChanged(object sender, EventArgs e)
{
PersonPanelViewModel.SearchCommand.Execute(null);
}
}
ViewModel - &gt; PersonPanelViewModel:
public class PersonPanelViewModel : ViewModelBase
{
private IPersonService _personService;
private decimal _personId = 0;
private string _titleLabel = string.Empty;
private string _filterPlaceholderText = string.Empty;
private string _resultText = string.Empty;
private bool _resultTextVisible = true;
public PersonPanelViewModel(IPersonService personService)
{
_personService = personService;
// Init Filter
Filter = new PersonFilter();
// Init Commands
SearchCommand = new RelayCommand(Search);
}
public ICommand SearchCommand { get; set; }
public PersonFilter Filter
{
get;
private set;
}
public string ResultText
{
get
{
return _resultText;
}
set
{
Set(() => ResultText, ref _resultText, value);
}
}
public bool ResultTextVisible
{
get
{
return _resultTextVisible;
}
set
{
Set(() => ResultTextVisible, ref _resultTextVisible, value);
}
}
public string FilterPlaceholderText
{
get
{
return _filterPlaceholderText;
}
set
{
Set(() => FilterPlaceholderText, ref _filterPlaceholderText, value);
}
}
public string TitleLabel
{
get
{
return _titleLabel;
}
set
{
Set(() => TitleLabel, ref _titleLabel, value);
}
}
public decimal PersonId
{
get
{
return _PersonId;
}
set
{
Set(() => PersonId, ref _PersonId, value);
}
}
private async void Search()
{
//Reset
ResultText = string.Empty;
ResultTextVisible = false;
PersonId = 0;
if (Filter.PersonLookup != null && Filter.PersonLookup.Length >= 3)
{
//Call to Person Service
List<PersonResult> Person = await _personService.FindpersonByFilter(Filter);
if (Person.Count == 1)
{
PersonId = Person[0].PersonId;
ResultText = Person[0].PersonName;
ResultTextVisible = true;
}
}
}
}
在另一个视图中使用Control:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:components="clr-namespace:xxx.ViewElements.Components"
x:Class="xxx.MainPage">
<StackLayout Orientation="Vertical">
<components:PersonPanel x:Name="personPanel" TitleLabel="Person" FilterPlaceholderText="Type your search criteria here..."/>
</StackLayout>
</ContentPage>
我正在使用Autofac作为IOC容器。
你怎么看?我正在使用MVVM(这对我来说很新)?
有没有更好的方法来处理从视图中的事件(TextChanged)调用命令?
Code-Behind中的属性是什么(路由到ViewModel)?
修改 我将尝试描述,我想要实现的目标:
- &GT;通过上面的实现,所有这些都有效,但我不确定这是否正确......
感谢您的帮助!
亲切的问候, 彼得
答案 0 :(得分:0)
将事件映射到命令的方法与我执行的完全一样。
其余的有点令人困惑。一般模式是在控件中创建可绑定属性,这些属性在主机视图中实例化时公开给视图模型。下面是一个非常基本的样本结构:
public class TestLabelControl : Label
{
public static readonly BindableProperty TestTitleProperty = BindableProperty.Create< TestLabelControl, string> (p => p.TestTitle, null);
public string TestTitle {
get {
return (object)GetValue (TestTitleProperty);
}
set {
SetValue (TestTitleProperty, value);
}
}
}
public class TestContentPage : ContentPage
{
public TestContentPage()
{
var testLabel = new TestLabel();
testLabel.SetBinding<TestContentPageViewModel>(TestLabel.TestTitleProperty, vm => vm.TestLabelTitle, BindingMode.Default);
Content = testLabel;
}
}
public class TestContentPageViewModel
{
public string TestLabelTitle{get;set;}
public TestContentPageViewModel()
{
TestLabelTitle = "Something random";
}
}
然后,您将创建本机渲染器以在每个平台上处理绘图。
通过遵循这种方法,您可以保持代码分离和简洁。它似乎是一种稍微冗长的方式来完成任务,但它具有高度可扩展性和可配置性。