C#给Excel添加水印实例详解

 步骤4：保存并打开文件。

workbook.SaveToFile("水印.xlsx", ExcelVersion.Version2010);
System.Diagnostics.Process.Start("水印.xlsx");

 效果图：

全部代码：

using System;
using System.Drawing;
using System.Windows.Forms;
using Spire.Xls;
 
namespace Add_Watermark_To_Excel
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }
 
    private void button1_Click(object sender, EventArgs e)
    {
      //初始化一个新工作簿并加载要添加水印的文件
      Workbook workbook = new Workbook();
      workbook.LoadFromFile(@"C:UsersAdministratorDesktopsample.xlsx");
      //在页眉插入图片
      Font font = new System.Drawing.Font("arial", 40);
      String watermark = "内部资料";
      foreach (Worksheet sheet in workbook.Worksheets)
      {
        //调用DrawText()方法新建图片
        System.Drawing.Image imgWtrmrk = DrawText(watermark, font, System.Drawing.Color.LightCoral, System.Drawing.Color.White, sheet.PageSetup.PageHeight, sheet.PageSetup.PageWidth);
        //将页眉图片设置为左对齐
        sheet.PageSetup.LeftHeaderImage = imgWtrmrk;
        sheet.PageSetup.LeftHeader = "&G";
        //水印只会在此种模式下显现
        sheet.ViewMode = ViewMode.Layout;
      }
      workbook.SaveToFile("水印.xlsx", ExcelVersion.Version2010);
      System.Diagnostics.Process.Start("水印.xlsx");
    }
    <br>    private static System.Drawing.Image DrawText(String text, System.Drawing.Font font, Color textColor, Color backColor, double height, double width)
    {
      //创建一个指定宽度和高度的位图图像
      Image img = new Bitmap((int)width, (int)height);
      Graphics drawing = Graphics.FromImage(img);
      //获取文本大小
      SizeF textSize = drawing.MeasureString(text, font);
      //旋转图片
      drawing.TranslateTransform(((int)width - textSize.Width) / 2, ((int)height - textSize.Height) / 2);
      drawing.RotateTransform(-45);
      drawing.TranslateTransform(-((int)width - textSize.Width) / 2, -((int)height - textSize.Height) / 2);
      //绘制背景
      drawing.Clear(backColor);
      //创建文本刷
      Brush textBrush = new SolidBrush(textColor);
      drawing.DrawString(text, font, textBrush, ((int)width - textSize.Width) / 2, ((int)height - textSize.Height) / 2);
      drawing.Save();
      return img;
    }
 
  } 
}