xamarin - 如何在标签的新派生类中包含来自 StaticResource 的 StringFormat

Question

我有这个 XAML：

<Label Text="{Binding val1, StringFormat={StaticResource CommaInteger}}"/>
<Label Text="{Binding val2, StringFormat={StaticResource CommaInteger}}"/>

我想将其简化为：

<local:commaIntLbl Text="{Binding val1}"/>
<local:commaIntLbl Text="{Binding val2}"/>

我应该如何编码我的 commaIntLbl 类来实现这一点？

public class commaIntLbl : Label
{
    public commaIntLbl() : base()
    {
        SetDynamicResource(StyleProperty, "IntegerLabel");
        // How to refer its Text's string-format to the StaticResource CommaInteger?
    }
}

Answer 1

您可以在 val1 属性中设置字符串格式，如下所示，然后进行绑定。

 public string _val1;
    public string val1
    {
        get
        {
            return string.Format("Hello, {0}", _val1);
        }
        set
        {
            _val1 = value;
        }
    }

更新：

xml:

 <local:CommaIntLbl TextVal="{Binding val1}" />

自定义控件：

 public class CommaIntLbl : Label
{
    public CommaIntLbl() : base()
    { }
    private string _text;
    public string TextVal
    {
        get { return _text; }
        set
        {
            _text = value;
            OnPropertyChanged();
        }
    }
    public static readonly BindableProperty TextValProperty = BindableProperty.Create(
             nameof(TextVal),
             typeof(string),
             typeof(CommaIntLbl),
             string.Empty,
             propertyChanged: (bindable, oldValue, newValue) =>
             {
                 var control = bindable as CommaIntLbl;
                 control.Text = String.Format("Hello, {0}", newValue);
             });
}

后面的代码：

public string _val1;
    public string val1 { get; set; }

    public Page19()
    {
        InitializeComponent();
        val1 = "1234";
        this.BindingContext = this;
    }