Question

我有这个XAML，它使用自定义模板3次，然后再对ViewCell，Grid等进行硬编码：

<ContentPage.Content>
    <TableView Intent="Settings" HasUnevenRows="false" RowHeight="50" x:Name="atiSection">
        <TableView.Root>
            <TableSection Title="Set the amount of time that the answer will remain visible on the Play screen">
                <template:SwitchViewCellTemplate Text="{Binding [0].Name}" 
                    IsVisible="{Binding [0].IsSelected}" 
                    SelectAction="Handle_SelectAction" />
                <template:SwitchViewCellTemplate Text="{Binding [1].Name}" 
                    IsVisible="{Binding [1].IsSelected}" 
                    SelectAction="Handle_SelectAction" />
                <template:SwitchViewCellTemplate Text="{Binding [2].Name}" 
                    IsVisible="{Binding [2].IsSelected}" 
                    SelectAction="Handle_SelectAction" />
                <ViewCell Tapped="selectValue" >
                    <Grid VerticalOptions="CenterAndExpand" Padding="20,0" >
                        <local:StyledLabel Text="{Binding [3].Name}" HorizontalOptions="StartAndExpand" />
                        <local:StyledLabel IsVisible="{Binding [3].IsSelected}" TextColor="Gray" HorizontalOptions="End" Text="✓" />
                    </Grid>
                </ViewCell>

为了使内容更整洁，我创建了一个模板，该模板在此示例中使用了三次：

<?xml version="1.0" encoding="utf-8" ?>
<ViewCell xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:Japanese;assembly=Japanese"
          x:Class="Japanese.SwitchViewCellTemplate"
          x:Name="this" >
   <Grid VerticalOptions="CenterAndExpand" Padding="20,0" >
      <local:StyledLabel Text="{Binding Text, Source={x:Reference this}}" HorizontalOptions="StartAndExpand" />
      <local:StyledLabel IsVisible="{Binding IsVisible, Source={x:Reference this}}" TextColor="Gray" HorizontalOptions="End" Text="✓" />
   </Grid>
</ViewCell>

这是后端CS代码初始化：

    SSVViewModel[] AnswerTimeInterval = new[] {
            new SSVViewModel{  Id = 0, Name = ATI.Two.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 1, Name = ATI.Three.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 2, Name = ATI.Five.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 3, Name = ATI.Ten.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 4, Name = ATI.Fifteen.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 5, Name = ATI.Thirty.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 6, Name = ATI.Sixty.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 7, Name = ATI.ThreeHundred.Text(), IsSelected = false} ,
            new SSVViewModel{  Id = 8, Name = ATI.SixHundred.Text(), IsSelected = false} ,
        };
    public ATIPage()
    {
        InitializeComponent();
        atiSection.BindingContext = AnswerTimeInterval;
    }

页面首次显示时如下所示：

在我单击三个单元格中的第一个后，它变为：

有人有什么想法，为什么行中的文本最初显示时几乎没有高度，然后单击视图单元格时为什么会变大？

Answer 1

AndExpand LayoutOptions are only for use by a StackLayout，尽管我不确定这是否是问题的根本原因。将模板网格更改为以下似乎可以解决该问题：

   <Grid Padding="20,0">
      <Label Text="{Binding Text, Source={x:Reference this}}" 
             VerticalTextAlignment="Center"/>
      <Label HorizontalOptions="End" 
             IsVisible="{Binding IsVisible, Source={x:Reference this}}" 
             Text="✓"
             TextColor="Gray"
             VerticalTextAlignment="Center" />
   </Grid>

Xamarin.Forms创作者Jason Smith的

Performance tips也提到以下内容：

优选VerticalTextAlignment和HorizontalTextAlignment Label和VerticalOptions上HorizontalOptions的属性。

使用模板时，模板中网格的行高最初设置不正确吗？

1 个答案: