C# 将数据从自定义渲染器传递到自定义控件
我的项目中有以下C# 将数据从自定义渲染器传递到自定义控件,c#,.net,xamarin.forms,xamarin.android,C#,.net,Xamarin.forms,Xamarin.android,我的项目中有以下Xamarin.Forms控件: public partial class AutoCompleteView : Xamarin.Forms.View { public event EventHandler<TextChangedEventArgs> TextChanged; public static readonly BindableProperty TextProperty = BindableProperty.Create(
Xamarin.Forms
控件:
public partial class AutoCompleteView : Xamarin.Forms.View
{
public event EventHandler<TextChangedEventArgs> TextChanged;
public static readonly BindableProperty TextProperty = BindableProperty.Create(
propertyName: "Text",
returnType: typeof(string),
declaringType: typeof(string),
defaultBindingMode: BindingMode.TwoWay);
public static readonly BindableProperty SuggestionsProperty = BindableProperty.Create(
propertyName: "Suggestions",
returnType: typeof(IEnumerable<string>),
declaringType: typeof(ObservableCollection<string>),
defaultBindingMode: BindingMode.OneWay);
public IEnumerable<string> Suggestions
{
get => (IEnumerable<string>)GetValue(SuggestionsProperty);
set => SetValue(SuggestionsProperty, value);
}
public string Text
{
get => (string)GetValue(TextProperty);
set => SetValue(TextProperty, value);
}
public AutoCompleteView () : base()
{
InitializeComponent ();
}
private void OnTextChanged(TextChangedEventArgs e)
{
TextChanged?.Invoke(this, e);
}
}
公共部分类自动完成视图:Xamarin.Forms.View
{
公共事件事件处理程序文本已更改;
公共静态只读BindableProperty TextProperty=BindableProperty.Create(
propertyName:“文本”,
returnType:typeof(字符串),
declaringType:typeof(字符串),
defaultBindingMode:BindingMode.TwoWay);
公共静态只读BindableProperty SuggestionProperty=BindableProperty.Create(
propertyName:“建议”,
returnType:typeof(IEnumerable),
declaringType:typeof(ObservableCollection),
defaultBindingMode:BindingMode.OneWay);
公众的无数建议
{
get=>(IEnumerable)GetValue(SuggestionProperty);
set=>SetValue(SuggestionProperty,value);
}
公共字符串文本
{
get=>(字符串)GetValue(TextProperty);
set=>SetValue(TextProperty,value);
}
公共自动完成视图():base()
{
初始化组件();
}
私有void OnTextChanged(textchangedventargs e)
{
TextChanged?调用(this,e);
}
}
以及以下自定义Android渲染器:
public class AutoCompleteViewRenderer : Xamarin.Forms.Platform.Android.ViewRenderer<AutoCompleteView, AutoCompleteTextView>
{
public AutoCompleteViewRenderer(Context context) : base(context) { }
protected override void OnElementChanged(ElementChangedEventArgs<AutoCompleteView> e)
{
base.OnElementChanged(e);
if (e.OldElement != null || this.Element == null)
return;
var autoComplete = new AutoCompleteTextView(this.Context);
SetNativeControl(autoComplete);
this.Control.SetSingleLine();
this.Control.SetTextColor(Android.Graphics.Color.Black);
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (this.Element == null || this.Control == null)
return;
var autoComplete = (AutoCompleteView)sender;
this.Control.Text = autoComplete.Text;
if (autoComplete.Suggestions != null)
{
var suggestions = autoComplete.Suggestions.ToArray();
this.Control.Adapter = new ArrayAdapter<string>(Context, Resource.Layout.autoCompleteCell, suggestions);
}
}
}
公共类自动完成ViewRenderer:Xamarin.Forms.Platform.Android.ViewRenderer
{
公共自动完成视图渲染器(上下文):基本(上下文){}
受保护的覆盖无效OnElementChanged(ElementChangedEventArgs e)
{
基础。一个要素发生变化(e);
if(e.OldElement!=null | | this.Element==null)
返回;
var autoComplete=新的AutoCompleteTextView(this.Context);
SetNativeControl(自动完成);
this.Control.SetSingleLine();
this.Control.SetTextColor(Android.Graphics.Color.Black);
}
受保护的覆盖无效OnElementPropertyChanged(对象发送方,PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(发送方,e);
if(this.Element==null | | this.Control==null)
返回;
var autoComplete=(AutoCompleteView)发送方;
this.Control.Text=autoComplete.Text;
if(autoComplete.Suggestions!=null)
{
var-suggestions=autoComplete.suggestions.ToArray();
this.Control.Adapter=新的ArrayAdapter(上下文、Resource.Layout.autoCompleteCell、建议);
}
}
}
问题是控件不从呈现器接收文本(即既不调用
text
setter,也不调用绑定模型的setter)。如何解决这个问题?谢谢mjwills,我在这里发现了一个逻辑错误this.Control.Text=autoComplete.Text
显然应该反转(即autoComplete.Text=this.Control.Text
),因为this.Control
是本机控件,它应该将文本更改传递给自定义AutoCompleteView
您是说this.Control.Text=autoComplete.Text代码>不执行?如果在该行上放置一个断点并进行调试,该断点会被命中吗?会的。它在创建元素和焦点丢失时触发。但毕竟,绑定属性(Text
我的意思是)不会更新,而是保持为空。