更改我的自定义输入颜色一次单击我的按钮

Question

im正在处理渲染的custon条目，当我单击按钮时，我需要在自定义渲染中听到xaml的消息

我的xaml 中有这个代码

<local:MyEntry   eventRefresh="true">

当我点击我的按钮时，这个功能是激活的

private async void Execute(object sender)
{
var entry = ((MyEntry)view);
entry.eventRefresh = "false";

但是我的EntryRendered没有听到的变化

protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if (Control != null)
{
var element = Element as MyEntry;               

Answer 1

您应该将属性eventRefresh定义为BindableProperty。

在您的自定义条目中

using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Xamarin.Forms;
namespace xxx
{
public class MyEntry:Entry,INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public static readonly BindableProperty eventRefreshProperty = BindableProperty.Create("eventRefresh", typeof(bool), typeof(MyEntry), true,propertyChanged:(obj,oldValue,newValue)=> {
//var entry = obj as MyEntry;
//  entry.Text = newValue.ToString();

});
bool refresh;
public bool eventRefresh
{
get { return refresh; }
set {
if(refresh !=value)
{
refresh = value;
NotifyPropertyChanged("eventRefresh");
}
}
}

public MyEntry()
{
}

}
}

在xaml中

<StackLayout  VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand">

<local:MyEntry eventRefresh="{Binding Refresh}" BackgroundColor="{Binding BGcolor}" WidthRequest="200" HeightRequest="50" />
<Button Command="{Binding ClickCommand}"  />

</StackLayout>

视图中模型

public class MyViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
Color color;
public Color BGcolor
{
get { return color; }
set
{
if (color != value)
{
color = value;
NotifyPropertyChanged("BGcolor");
}
}
}

bool refresh;

public bool Refresh
{
get { return refresh; }
set
{
if (refresh != value)
{
refresh = value;
NotifyPropertyChanged("Refresh");
}
}
}

public ICommand ClickCommand { get; set; }
public MyViewModel()
{
BGcolor = Color.LightPink;

ClickCommand = new Command(()=> {

BGcolor = Color.Red;
});

}

}

在自定义渲染器中

using System.ComponentModel;
using Android.Content;
using xxx;
using xxx.Droid;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
[assembly:ExportRenderer(typeof(MyEntry),typeof(NyEntryRenderer))]
namespace xxx.Droid
{
public class NyEntryRenderer : EntryRenderer
{
public NyEntryRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if(Control!=null)
{
Element.TextChanged += Element_TextChanged;
}
}
private void Element_TextChanged(object sender, TextChangedEventArgs e)
{
// var content = Element.Text;
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == MyEntry.BackgroundColorProperty.PropertyName)
{
//  will been invoked when click button
}

}
}
}

Answer 2

这样创建视图模型

public class YourViewModel
{
public Command command
{
get
{
return new Command(() => {
//Change here button background colors
BackgroundColor = Color.Green; 
});
}
}

private _backgroundColor = Color.White;
public Color BackgroundColor
{
get { return _backgroundColor;}
set
{
if (value == _backgroundColor)
return;
_backgroundColor = value;
NotifyOnPropertyChanged(nameof(BackgroundColor));
}
}

}

您的XAML

<local:MyEntry Text="{Binding Password}" Placeholder="Enter"  />
<Button Text="send" Command="{Binding command}" BackgroundColor="{Binding BackgroundColor}"></Button>