使用zxing扫描条形码

Question

<zxing:ZXingScannerView IsScanning="True" OnScanResult="OnScanResult"/>我在xaml文件上有这个，但是我想使用mvvm，所以我在视图模型中有onscanresult平均处理器。我怎样才能用它来代替代码背后的那个呢？

public void OnScanResult(ZXing.Result result)
{
    Device.BeginInvokeOnMainThread(() =>
    {
        ScanResult = result.Text + " (type: " + result.BarcodeFormat + ")";
    });
}

Answer 1

如果你不想使用某个行为，只需创建一个新版本的ContentPage来创建一个事件来执行命令：

    public class ZxingContentPage : ZXingScannerPage
{
    public static readonly BindableProperty ScanResultCommandProperty =
        BindableProperty.Create(
            nameof(ScanResultCommand),
            typeof(ICommand),
            typeof(ZxingContentPage),
            default(ICommand)
            );

    public ICommand ScanResultCommand
    {
        get { return (ICommand)GetValue(ScanResultCommandProperty); }
        set { SetValue(ScanResultCommandProperty, value); }
    }

    public ZxingContentPage(MobileBarcodeScanningOptions options) : base(options)
    {
        OnScanResult += ZxingContentPage_OnScanResult;
    }

    private void ZxingContentPage_OnScanResult(ZXing.Result result)
    {
        if (ScanResultCommand?.CanExecute(result) == true)
        {
            ScanResultCommand.Execute(result);
        }
    }
}

然后像下面这样使用它：

<?xml version="1.0" encoding="utf-8" ?>
<views:ZxingContentPage
  x:Class="NameSpace.Zxing.ZxingMobileScannerView"
  xmlns="http://xamarin.com/schemas/2014/forms"
  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
  xmlns:views="clr-namespace:QRST.Views.Generic"
  IsScanning="True"
  ScanResultCommand="{Binding ZxingScanResultCommand}" />

祝好运

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