C#应用NPOI实现导出EXcel表格中插入饼状图（可实现动态数据生成）

我就是我 2021-12-21 13:35 344阅读 0赞

一、思路：   1、excel是可以通过NPOI插入图片的；

2、C\#通过NPOI生成饼状图；

3、把生成的饼状图以字节流的形式插入到表格

二、看代码：

#region 生成饼图图例
            /// <summary>
            /// 生成饼图饼图的颜色随机产生
            /// </summary>
            /// <param name="width">图片宽度</param>
            /// <param name="height">图片高度</param>
            /// <param name="radius">饼图半径</param>
            /// <param name="data">数据源</param>
            /// <param name="legends">图例</param>
            /// <returns></returns>
            public static Bitmap GetPieGraphic(int width, int height, int radius, float[] data, string[] legends)
            {
                if (data != null)
                {
                    string familyName = "Arial";
                    Bitmap objbitmap = new Bitmap(width, height);
                    Graphics objgraphics = Graphics.FromImage(objbitmap);
                    objgraphics.Clear(Color.White);
                    //抗锯齿   
                    objgraphics.SmoothingMode = SmoothingMode.HighQuality;
                    //高质量的文字 
                    objgraphics.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
                    //像素均偏移0.5个单位，以消除锯齿 
                    objgraphics.PixelOffsetMode = PixelOffsetMode.Half;
                    //定位饼图绘制的位置
                    Rectangle rect = new Rectangle(width / 2, height / 6, radius, radius);
                    Random random = new Random();
                    float currentdegree = 0.0f;
                    float Total = data.Sum();
                    List<Color>  listColor =new List<Color>();
                    for (int i = 0; i < data.Length; i++)
                    {
                        Color temC = Color.FromArgb(random.Next(255), random.Next(255), random.Next(255));
                        listColor.Add(temC);
                        SolidBrush brush = new SolidBrush(temC);
                        objgraphics.FillPie(brush, rect, currentdegree, Convert.ToSingle(data[i] / Total * 360));
                        currentdegree += Convert.ToSingle(data[i] / Total * 360);
                    }
                    //放置图例 
                    PointF basePoint = new PointF(10, 20);
                    //色块的大小 
                    SizeF theSize = new SizeF(45, 16);
                    //第一个色块的说明文字的位置          
    
                    PointF textPoint = new PointF(basePoint.X + 50, basePoint.Y);
                    for (int j = 0; j < listColor.Count; j++)
                    {
                        RectangleF baseRectangle = new RectangleF(basePoint, theSize);
                        //画代表色块             
    
                        objgraphics.FillRectangle(new SolidBrush(listColor[j]), baseRectangle);
                        string temstr = String.Format("{0}%", (data[j] / Total * 100).ToString("#0.00"));
                        objgraphics.DrawString(legends[j] + "  " + temstr, new Font(familyName, 11), Brushes.Black, textPoint);
                        basePoint.Y += 30;
                        textPoint.Y += 30;
                    }
                    return objbitmap;
                }
                else
                {
                    return null;
                }
            }
            /// <summary>
            /// 将BitMap类型的图像数据转换成byte[]
            /// </summary>
            /// <param name="bitmap">图像数据</param>
            /// <returns></returns>
            public static byte[] Bitmap2Byte(Bitmap bitmap)
            {
                using (MemoryStream stream = new MemoryStream())
                {
                    bitmap.Save(stream, ImageFormat.Jpeg);
                    byte[] data = new byte[stream.Length];
                    stream.Seek(0, SeekOrigin.Begin);
                    stream.Read(data, 0, Convert.ToInt32(stream.Length));
                    return data;
                }
            }
            #endregion 生成饼图图例

三、在处理表格数据出插入下面代码：

//legends和data可以是动态数据
    String[] legends = {
        "A满意","B基本满意","C不满意" };
                    float[] data = {
        1,3,1 };
                    Bitmap bitmap = GetPieGraphic(200,200,100,data,legends);
                    var row101 = sheet.CreateRow(82);
                    row101.Height = 80 * 20;
                    //将图片文件读入一个字符串
                    byte[] bytes = Bitmap2Byte(bitmap);
                    int pictureIdx = workbook.AddPicture(bytes, PictureType.JPEG);
                    HSSFPatriarch patriarch = (HSSFPatriarch)sheet.CreateDrawingPatriarch();
                    // 插图片的位置  HSSFClientAnchor（dx1,dy1,dx2,dy2,col1,row1,col2,row2) 后面再作解释
                    HSSFClientAnchor anchor = new HSSFClientAnchor(100, 100, 0, 0, 1, 82, 6, 94);
                    //把图片插到相应的位置
                    HSSFPicture pict = (HSSFPicture)patriarch.CreatePicture(anchor, pictureIdx);

转载于:https://www.cnblogs.com/lijl/p/10718741.html