在 Xamarin.forms 网格布局中绑定列定义宽度属性

Question

我正在尝试将网格布局中列定义的宽度属性设置为可绑定属性，它给了我这个语句System.NotSupportedException: Don't know about Xamarin.Forms.GridLength我想要做的就是绑定列定义宽度相关通过在我的页面 popuppage1 中与名为“w”的属性绑定来设置设备尺寸，而不是将其与我的 popupentity class 中的属性绑定，所以我知道我在这里做错了什么，提前谢谢我的代码如下：

popuppage1.xaml.cs

namespace DOTFORMS3.Views{   
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class popuppage1 : Rg.Plugins.Popup.Pages.PopupPage
{
    public int width = (int)DeviceDisplay.MainDisplayInfo.Width;
    public int height = (int)DeviceDisplay.MainDisplayInfo.Height;
    public GridLength w { get; set; }
    public GridLength h { get; set; }       
    public popuppage1()
    {
        InitializeComponent();
        var dbconn = new SQLiteConnection(Model.HelperMethods.dbPath);
        dbconn.CreateTable<popupentity>();
        mytb = dbconn.Table<popupentity>().ToList();
        MCET = new ObservableCollection<popupentity>(mytb);
        InitializeComponent();
        this.BindingContext = this;
        dbconn.Close();
       
        w = (width-20) / 2;
        h = (width - 20) / 2;
        Padding = 20;
    }
    public static List<popupentity> mytb { get; set; } = new List<popupentity>();
    public ObservableCollection<popupentity> MCET { get; set; }

    private void MTZ_ItemTapped(object sender, ItemTappedEventArgs e)
    {            
        var product = e.Item as popupentity;
        var xx = BindingContext as popuppage1;
    }  
}

这是我的 xaml 代码popuppage1.xaml

<pages:PopupPage     
xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
xmlns:animations="clr-namespace:Rg.Plugins.Popup.Animations;assembly=Rg.Plugins.Popup"
x:Class="DOTFORMS3.Views.popuppage1">      
    <ScrollView >
    <ListView HasUnevenRows="True" ItemsSource="{Binding MCET }" SelectionMode="None"  >
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell >
                    <Frame>
                        <StackLayout>
                            <Label Text="{Binding DIS1}" IsVisible="{Binding isDIS1}"></Label>
                              <Grid>
                                    <Grid.ColumnDefinitions >
                                        <ColumnDefinition  Width="{Binding w}">/ColumnDefinition>
                                        <ColumnDefinition  Width="{Binding w}" ></ColumnDefinition>
                                    </Grid.ColumnDefinitions>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="{Binding w}" ></RowDefinition>
                                        <RowDefinition Height="{Binding w}"></RowDefinition>
                                    </Grid.RowDefinitions>
                                <Image Grid.Column="0" Grid.Row="0" Source="{Binding image1}"></Image>
                                <Image Grid.Column="0" Grid.Row="1" Source="{Binding image2}"></Image>
                                <Image Grid.Column="1" Grid.Row="1" Source="{Binding image3}"></Image>
                                <Image Grid.Column="1" Grid.Row="0" Source="{Binding image4}"></Image>
                             </Grid>                                                                
                        </StackLayout>
                    </Frame>
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</ScrollView></pages:PopupPage>

这是我的弹出式 class

public class popupentity : TableEntity
{
    public int width = (int)DeviceDisplay.MainDisplayInfo.Width;
    public int height = (int)DeviceDisplay.MainDisplayInfo.Height;
   public popupentity()
    {
        w = (width - 20) / 2;
        h = (width - 20) / 2;
    }

    [PrimaryKey, AutoIncrement, Column("_id44")]
    public GridLength w { get; set; }
    public GridLength h { get; set; }
   
}