http://www.bubuko.com/infodetail-1923328.html

需要將 &#x 替換成 \u 最終是\ue603

 //使用方法
protected override void OnShown(EventArgs e)
        {
            base.OnShown(e);

            ImageFont.AddFontFile("./Properties/fonts/fontawesome-webfont.ttf");
            toolStripButton1.Image = GetFontImage("\uf002", Color.Red,20);

            toolStripButton1.Text = "查詢";
            toolStripButton1.Font = new Font(ImageFont.Families[0], 20);


        }

//字型圖示生成圖示
public static Image GetFontImage(string fontIco, Color color, int size)
        {
            var bmp = new Bitmap(size, size);
            var g = Graphics.FromImage(bmp);
            g.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
            g.InterpolationMode = InterpolationMode.HighQualityBilinear;
            g.PixelOffsetMode = PixelOffsetMode.HighQuality;
            g.SmoothingMode = SmoothingMode.HighQuality;

            var ch = fontIco;
            var font = GetAdjustedFont(g, ch, size, size, 4, true);
            var stringSize = g.MeasureString(ch, font, size);
            float w = stringSize.Width;
            float h = stringSize.Height;
            float left = (size - w) / 2;
            float top = (size - h) / 2;
            // Draw string to screen.
            var brush = new SolidBrush(color);
            g.DrawString(ch, font, brush, new PointF(left, top));
            return bmp;
        }

        private static Font GetAdjustedFont(Graphics g, string graphicString, int containerWidth, int maxFontSize, int minFontSize, bool smallestOnFail)
        {
            for (double adjustedSize = maxFontSize; adjustedSize >= minFontSize; adjustedSize = adjustedSize - 0.5)
            {
                Font testFont = GetIconFont((float)adjustedSize);
                SizeF adjustedSizeNew = g.MeasureString(graphicString, testFont);
                if (containerWidth > Convert.ToInt32(adjustedSizeNew.Width))
                {
                    return testFont;
                }
            }
            return GetIconFont(smallestOnFail ? minFontSize : maxFontSize);
        }
        private static Font GetIconFont(float size)
        {
            return new Font(ImageFont.Families[0], size, GraphicsUnit.Point);
        }