Question

我有这段代码：

<?xml version="1.0" encoding="UTF-8"?>
<ViewCell xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="CommentBlock">
    <Grid HeightRequest="60" VerticalOptions="CenterAndExpand" Padding="20,10" BackgroundColor="#EAEAF1">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>
        <Label Style="{DynamicResource ListItemDetailTextStyleStyle}" TextColor="#59595F" Text="ABC" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" />
    </Grid>
</ViewCell>

现在它已在XAML中实现，但我需要在C＃中实现，并且可以将文本消息（当前为ABC）和高度（50）设置为参数。

有人可以提供一些建议，告诉我如何将其作为一个类实现，然后我可以将其添加到我的应用程序中：

new CommentBlock(60, "ABC");

Answer 1

我相信你应该能够通过在CommentBlock的代码隐藏中添加构造函数来实现这一点，并且仍然继续使用基于XAML的CommentBlock：

public CommentBlock(string text, double height)
{
    InitializeComponent();

    _commentLbl.Text = text;
    _containerGrid.HeightRequest = height;
}

并在CommentBlock的XAML中添加对内部控件的命名引用：

<Grid x:Name="_containerGrid" ..>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
    </Grid.ColumnDefinitions>
    <Label x:Name="_commentLbl" ../>
</Grid>

编辑：08/23

但是如果你特别想要基于C＃的实现，那么下面将是你的XAML的C＃等价物（我为comment-text添加了几个可绑定属性，并且为了允许基于XAML的用法添加了grid-height）。

public class CommentBlockCell : ViewCell
{
    public static readonly BindableProperty CommentTextProperty = BindableProperty.Create(
        "CommentText", typeof(string), typeof(CommentBlockCell),
        defaultValue: null);

    public string CommentText
    {
        get { return (string)GetValue(CommentTextProperty); }
        set { SetValue(CommentTextProperty, value); }
    }

    public static readonly BindableProperty GridHeightProperty = BindableProperty.Create(
        "GridHeight", typeof(double), typeof(CommentBlockCell),
        defaultValue: 30.0);

    public double GridHeight
    {
        get { return (double)GetValue(GridHeightProperty); }
        set { SetValue(GridHeightProperty, value); }
    }

    public CommentBlockCell() 
    {
        BuildControl();
    }

    public CommentBlockCell(double gridHeight, string comment)
    {
        CommentText = comment;
        GridHeight = gridHeight;

        BuildControl();
    }

    private void BuildControl()
    {
        var grid = new Grid
        {
            VerticalOptions = LayoutOptions.CenterAndExpand,
            Padding = new Thickness(20, 10),
            BackgroundColor = Color.FromHex("#EAEAF1"),
            RowDefinitions = new RowDefinitionCollection {
                new RowDefinition { Height = GridLength.Auto }
            },
            ColumnDefinitions = new ColumnDefinitionCollection {
                new ColumnDefinition { Width = GridLength.Auto }
            }
        };

        var label = new Label
        {
            HorizontalOptions = LayoutOptions.FillAndExpand,
            VerticalOptions = LayoutOptions.CenterAndExpand
        };
        //label.SetDynamicResource(VisualElement.StyleProperty, "ListItemDetailTextStyleStyle");

        label.SetBinding(Label.TextProperty, new Binding(nameof(CommentText), source: this));
        grid.SetBinding(VisualElement.HeightRequestProperty, new Binding(nameof(GridHeight), source: this));

        grid.Children.Add(label);
        View = grid;
    }
}

用法可以是：

new CommentBlockCell(60, "ABC");

或者在XAML中：

<local:CommentBlockCell CommentText="ABC" GridHeight="60" />

如何在C＃中实现添加ViewCell，Grid和Label作为类？

1 个答案: