小编Chr*_*Way的帖子

实际上,根据标题,当基类是通用的时,如何在XAML中设置依赖属性？当我尝试这样做时,我得到一个NullReferenceException,从后面的代码设置属性工作正常.它也适用于基类不通用的情况.我正在使用.NET4

以下是一些示例代码:

WindowBase.cs

using System.Windows;

namespace GenericDependencyPropertyTest
{
    public class WindowBase<ViewModel> : Window
    {
        public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register(
        "Header", typeof(string), typeof(WindowBase<ViewModel>), new PropertyMetadata("No Header Name Assigned"));

        public string Header
        {
            get { return (string)GetValue(HeaderProperty); }
            protected set { SetValue(HeaderProperty, value); }
        }
        protected virtual ViewModel Model { get; set; }
    }
}

MainWindow.xaml

<local:WindowBase x:Class="GenericDependencyPropertyTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:GenericDependencyPropertyTest"
        x:TypeArguments="local:IMyViewModel"
        Title="MainWindow" Height="350" Width="525" Header="Test">
    <Grid>

    </Grid>
</local:WindowBase>

MainWindow.xaml.cs

namespace GenericDependencyPropertyTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml …

我正在尝试设置Google Play等标签,我正在按照本指南转换为C#,但在调用时会抛出异常tabLayout.SetupWithViewPager.活动的代码是这样的:

public class MainActivity : FragmentActivity
{
    protected override void OnCreate(Bundle bundle) {
        base.OnCreate(bundle);
        SetContentView(Resource.Layout.Main);

        var viewPager = FindViewById<ViewPager>(Resource.Id.viewpager);
        viewPager.Adapter = new SampleFragmentPagerAdapter(SupportFragmentManager, this);

        var tabLayout = FindViewById<TabLayout>(Resource.Id.sliding_tabs);
        tabLayout.SetupWithViewPager(viewPager);
    }
}

异常的堆栈跟踪是:

07-28 23:08:39.068 I/MonoDroid( 4040): UNHANDLED EXCEPTION:
07-28 23:08:39.071 I/MonoDroid( 4040): Android.Views.InflateException: Exception of type 'Android.Views.InflateException' was thrown.
07-28 23:08:39.071 I/MonoDroid( 4040): at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <IL 0x00011, 0x0004b>
07-28 23:08:39.071 I/MonoDroid( 4040): at Android.Runtime.JNIEnv.CallVoidMethod (intptr,intptr,Android.Runtime.JValue*) [0x00063] in /Users/builder/data/lanes/1879/5f55a9ef/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:571
07-28 23:08:39.071 I/MonoDroid( 4040): at Android.Support.Design.Widget.TabLayout.SetupWithViewPager …