Xamarin表单中的占位符文本对齐方式

2 回答

• 3

  您需要为每个平台创建一个自定义渲染器，以使占位符像这样：

  public class PlaceholderEditor : Editor
  {
      public static readonly BindableProperty PlaceholderProperty =
          BindableProperty.Create<PlaceholderEditor, string>(view => view.Placeholder, String.Empty);
  
      public PlaceholderEditor()
      {
      }
  
      public string Placeholder
      {
          get
          {
              return (string)GetValue(PlaceholderProperty);
          }
  
          set
          {
              SetValue(PlaceholderProperty, value);
          }
      }
  }
  
  public class PlaceholderEditorRenderer : EditorRenderer
  {
      public PlaceholderEditorRenderer()
      {
      }
  
      protected override void OnElementChanged(
          ElementChangedEventArgs<Editor> e)
      {
          base.OnElementChanged(e);
  
          if (e.NewElement != null)
          {
              var element = e.NewElement as PlaceholderEditor;
              this.Control.Hint = element.Placeholder;
          }
      }
  
      protected override void OnElementPropertyChanged(
          object sender,
          PropertyChangedEventArgs e)
      {
          base.OnElementPropertyChanged(sender, e);
  
          if (e.PropertyName == PlaceholderEditor.PlaceholderProperty.PropertyName)
          {
              var element = this.Element as PlaceholderEditor;
              this.Control.Hint = element.Placeholder;
          }
      }
  }
  

  回复于 2024-04-19T18:59:37+08:00
• 1

  无需更多自定义，只需在XAML中使用： HorizontalTextAlignment="Center"

  回复于 2024-04-19T18:59:37+08:00