DrawText方法中当前上下文错误下不存在名称“e”

Question

我在C＃中编写的方法中渲染了一些Bitmaps。

我正在学习使用TextRenderer.DrawText()方法在位图上绘制文本。摘录如下：

TextRenderer.DrawText(e.Graphics, "Regular Text", SystemFonts.DefaultFont, new Point(10, 10), SystemColors.ControlText);

但是，在e.Graphics下，我收到错误The name "e" does not exist under the current context。

我想知道可能是什么问题？

我的Render方法的代码片段，使用Rhino-Common库：

    protected override void Render(Grasshopper.GUI.Canvas.GH_Canvas canvas, Graphics graphics, Grasshopper.GUI.Canvas.GH_CanvasChannel channel) {
        base.Render(canvas, graphics, channel);

        if (channel == Grasshopper.GUI.Canvas.GH_CanvasChannel.Wires) {
            var comp = Owner as KT_HeatmapComponent;
            if (comp == null)
                return;

            List<HeatMap> maps = comp.CachedHeatmaps;
            if (maps == null)
                return;

            if (maps.Count == 0)
                return;

            int x = Convert.ToInt32(Bounds.X + Bounds.Width / 2);
            int y = Convert.ToInt32(Bounds.Bottom + 10);

            for (int i = 0; i < maps.Count; i++) {
                Bitmap image = maps[i].Image;
                if (image == null)
                    continue;

                Rectangle mapBounds = new Rectangle(x, y, maps[i].Width, maps[i].Height);
                mapBounds.X -= mapBounds.Width / 2;

                Rectangle edgeBounds = mapBounds;
                edgeBounds.Inflate(4, 4);

                GH_Capsule capsule = GH_Capsule.CreateCapsule(edgeBounds, GH_Palette.Normal);
                capsule.Render(graphics, Selected, false, false);
                capsule.Dispose();

                graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
                graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
                graphics.DrawImage(image, mapBounds);
                graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Default;
                graphics.DrawRectangle(Pens.Black, mapBounds);
                TextRenderer.DrawText(e.Graphics, "Regular Text", SystemFonts.DefaultFont, new Point(10, 10), SystemColors.ControlText);

                y = edgeBounds.Bottom - (mapBounds.Height) - 4;
            }
        }
    }

上面的代码片段将热图呈现到Grasshopper画布上，如下所示：

但是，我有兴趣在其上添加标题和x / y轴文本。

Answer 1

您发布的代码看起来像设计在Paint事件处理程序中（因为e是事件处理程序的适当类型EventArgs的惯用变量名称， Graphics是PaintEventArgs）的属性。

由于您已经传递了Graphics个对象，因此您应该能够在代码段中替换e.Graphics，并将graphics参数传递到您的Render功能。您可以将此行添加到该函数：

TextRenderer.DrawText(graphics, "Regular Text", SystemFonts.DefaultFont, new Point(10, 10), SystemColors.ControlText);