问Xamarin.Forms将IsEnable设置为true不起作用
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Stack Overflow用户

提问于 2019-12-17 18:36:22

回答 1查看 85关注 0票数 0

我正在使用Xamarin.Forms，我尝试使用禁用按钮，然后在按钮操作完成时启用它，当我禁用它时，该按钮实际上会变为禁用状态，但当我启用它时，它仍然被禁用，我做错了什么？下面是我的完整方法：

private void OnCameraScan(object sender, EventArgs e)
{
    ScanLicence.IsEnabled = false;

    var barcodeScanView = new ZXing.Net.Mobile.Forms.ZXingScannerView
    {
        HeightRequest = 200
    };

    ScannerWrapper.HeightRequest = 200;
    ScannerWrapper.IsVisible = true;


    var options = new MobileBarcodeScanningOptions
    {
        TryHarder = true,
        CameraResolutionSelector = HandleCameraResolutionSelectorDelegate,
        PossibleFormats = new List<BarcodeFormat> { BarcodeFormat.PDF_417 },
    };

    barcodeScanView.OnScanResult += (result) =>
    {
        barcodeScanView.IsScanning = false;

        Console.WriteLine(result);

        var data = result.Text.Split('\n');

        foreach (var line in data)
        {

            if (line.Length > 3)
            {
                var code = line.Substring(0, 3);
                var value = line.Substring(3);

                Xamarin.Forms.Device.BeginInvokeOnMainThread(() =>
                {
                    switch (code)
                    {
                        case "DCT":
                            userClass.Customer_Name = value.Trim();
                            Customer_Name.Text = value.Trim();
                            break;
                        case "DCS":
                            userClass.Customer_LName = value.Trim();
                            Customer_LName.Text = value.Trim();
                            break;
                        case "DAI":
                            userClass.City = value.Trim();
                            City.Text = value.Trim();
                            break;
                        case "DAG":
                            userClass.Address1 = value.Trim();
                            Address1.Text = value.Trim();
                            break;
                        case "DAK":
                            userClass.Zip = value.Trim();
                            Zip.Text = value.Trim();
                            break;
                    }

                });


            }
        }

        ScanLicence.IsEnabled = true;


    };

    barcodeScanView.Options = options;
    barcodeScanView.IsScanning = true;

    ScannerWrapper.Children.Add(barcodeScanView);

}

有问题的按钮是ScanLicence。

<Button x:Name="ScanLicence" Text="Scan Licence" Clicked="OnCameraScan" Style="{StaticResource ButtonStyle}" WidthRequest="50" />

这是针对iOS应用程序的。

xamarin

xamarin.forms

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回答 1

Stack Overflow用户

发布于 2019-12-18 23:44:47

您可以尝试将调用事件的对象强制转换为"Button“，然后禁用它。在你的代码的末尾，你可能会得到类似这样的东西：

// Safe casting to Button instance.
Button button = sender as Button;

// Make sure the cast didn't return a null value
if(button == null) return;

// Set enable to true
button.IsEnabled = true; // You can also use button.IsEnabled = !button.IsEnabled