UWP应用中是否存在类似WinForms OnPaint的自定义组件绘制方法？

UWP中没有和WinForms OnPaint完全等价的方法，要实现自定义绘制逻辑，最实用的方案是使用Win2D（微软官方的2D图形库），它的API设计和WinForms的Graphics类非常接近，能轻松迁移你的绘制逻辑。以下是针对你提供的WinForms按钮绘制代码，给出的UWP实现方案：

步骤1：安装Win2D NuGet包 #

在你的UWP项目中，安装Microsoft.Graphics.Win2D.Uwp包，这是实现自定义绘制的基础。

步骤2：创建自定义控件并实现绘制逻辑 #

继承UserControl，内部嵌入CanvasControl，并在其Draw事件中实现绘制逻辑，对应WinForms的OnPaint方法：

using Microsoft.Graphics.Canvas;
using Microsoft.Graphics.Canvas.Geometry;
using Windows.UI;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;

public class CustomButton : UserControl
{
    private CanvasControl _canvas;
    public enum Mode { True, False }

    // 定义对应WinForms中的属性
    public ImageSource Image { get; set; }
    public Mode ImageOnly { get; set; }
    public Color ButtonColor { get; set; } = Colors.LightGray;
    public Color Foreground { get; set; } = Colors.Black;
    public string Text { get; set; }
    public CanvasTextFormat ButtonFont { get; set; } = new CanvasTextFormat
    {
        FontSize = 14,
        HorizontalAlignment = CanvasHorizontalAlignment.Left,
        VerticalAlignment = CanvasVerticalAlignment.Top
    };

    public CustomButton()
    {
        _canvas = new CanvasControl();
        _canvas.Draw += Canvas_Draw;
        this.Content = _canvas;
        // 监听控件尺寸变化，触发重绘
        this.SizeChanged += (s, e) => _canvas.Invalidate();
    }

    private void Canvas_Draw(CanvasControl sender, CanvasDrawEventArgs args)
    {
        var session = args.DrawingSession;
        float buttonHeight = (float)ActualHeight;
        float buttonWidth = (float)ActualWidth;

        float imgHeight = buttonHeight;
        float imgWidth = buttonHeight;
        float textPadding = (buttonHeight - (float)ButtonFont.FontSize) / 2;
        float textStartX = imgWidth + textPadding;
        float textStartY = textPadding - 3;

        // 绘制圆角背景（对应WinForms的FillRoundedRectangle）
        var rect = CanvasGeometry.CreateRoundedRectangle(session, 0, 0, buttonWidth, buttonHeight, 10, 10);
        session.FillGeometry(rect, ButtonColor);

        if (Image == null) return;

        // 转换ImageSource为CanvasBitmap
        var bitmap = CanvasBitmap.LoadAsync(session, Image as Windows.UI.Xaml.Media.Imaging.BitmapImage).GetAwaiter().GetResult();

        if (ImageOnly == Mode.True)
        {
            // 居中绘制图片
            float imgX = (buttonWidth - imgWidth) / 2;
            float imgY = (buttonHeight - imgHeight) / 2;
            session.DrawImage(bitmap, imgX, imgY, imgWidth, imgHeight);
        }
        else
        {
            // 左图右文
            session.DrawImage(bitmap, 0, 0, imgWidth, imgHeight);
            session.DrawText(Text, textStartX, textStartY, Foreground, ButtonFont);
        }
    }

    // 控件卸载时释放CanvasControl资源
    protected override void OnUnloaded(object sender, RoutedEventArgs e)
    {
        _canvas.RemoveFromVisualTree();
        _canvas = null;
        base.OnUnloaded(sender, e);
    }
}

关键对应点说明 #

• WinForms的PaintEventArgs.Graphics对应UWP中Win2D的CanvasDrawingSession，所有绘制操作都通过它完成
• 圆角矩形绘制：用CanvasGeometry.CreateRoundedRectangle替代自定义的FillRoundedRectangle
• 图片绘制：DrawImage方法参数和WinForms类似，需要先将ImageSource转换为CanvasBitmap
• 文本绘制：DrawText替代DrawString，用CanvasTextFormat控制字体样式

如果你不想依赖Win2D，也可以继承CustomControl并重写OnRender方法，使用XAML的DrawingContext进行绘制，但这种方式的API功能有限，复杂图形（比如圆角、自定义图片布局）实现起来不如Win2D便捷。

内容的提问来源于stack exchange，提问作者Borisonekenobi