MvvmCross中的BackgroundColor绑定

Question

我正在尝试使用绑定BackgroundColor属性更改微调器的背景颜色,如下所示,但它没有任何效果.

View.axml

<mvvmcross.droid.support.v7.appcompat.widget.MvxAppCompatSpinner
    android:layout_width="115dp"
    android:layout_height="match_parent"
    android:textColor="@color/primary_text"
    local:MvxItemTemplate="@layout/single"
    local:MvxBind="ItemsSource SingleList; SelectedItem SingleSize ; BackgroundColor SingleBackgroundValueConverter(IsSingleValid)" />

Converter.cs

public class SingleBackgroundValueConverter: MvxValueConverter<bool>
{
  protected override MvxColor Convert(bool value, object parameter, CultureInfo culture)
  {
    // either white or red
    return value ? new MvxColor(255, 255, 255) : new MvxColor(255, 0, 0);
  }
}

在下面,我能够看到警报弹出,但背景颜色根本没有变化.

ViewModel.cs

public void Save()
{
    if (!isExist)
    {
         OnExit(this, null);
    }
    else
    {
        _isSingleValid= false;
        RaisePropertyChanged(() => IsSingleValid);
        Mvx.Resolve<IUserDialogs>().Alert("It is not valid");
    }
}

private bool _isSingleValid = true;
public bool IsSingleValid
{
    get { return _isSingleValid; }
    set
    {
        _isSingleValid= value;
        RaisePropertyChanged(() => IsSingleValid);
    }
}

Answer 1

BackgroundColor是Color pluign的一部分.

第一步是确保已安装它.

 Install-Package MvvmCross.Plugin.Color

然后继承您的转换器MvxColorValueConverter<T>.

public class SingleBackgroundValueConverter : MvxColorValueConverter<bool>
{
    protected override MvxColor Convert(bool value, object parameter, CultureInfo culture)
    {
        return value ? new MvxColor(255, 255, 255) : new MvxColor(255, 0, 0);
    }
}

然后你必须在绑定中更改转换器名称,因为mvvmcross命名约定会剥离ValueConverter部件.

local:MvxBind="ItemsSource SingleList; SelectedItem SingleSize ; BackgroundColor SingleBackground(IsSingleValid)"