c#/vb.net 添加 excel 文本水印和图片水印-凯发线上登陆下载网址

有时我们需要在excel工作表中添加水印来达到保护文档的目的。该文将介绍如何使用c# 在excel表格中添加自定义页眉，再添加图片或艺术字来模拟excel水印。excel 水印在正常模式下不可见，仅在页面布局模式或打印预览模式才可见。

效果图：

using spire.xls;
using system.drawing;
using system;
namespace addwatermarktoexcel
{
    class program
    {
        static void main(string[] args)
        {
            //加载示例文档
            workbook workbook = new workbook();
            workbook.loadfromfile("sample.xlsx");
            //设置文本和字体大小
            font font = new system.drawing.font("仿宋", 40);
            string watermark = "内部文档";         
 
            foreach (worksheet sheet in workbook.worksheets)
            {
                //调用drawtext() 方法插入图片
                system.drawing.image imgwtrmrk = drawtext(watermark, font, system.drawing.color.lightcoral, system.drawing.color.white, sheet.pagesetup.pageheight, sheet.pagesetup.pagewidth);
                //将图片设置为页眉
                sheet.pagesetup.leftheaderimage = imgwtrmrk;
                sheet.pagesetup.leftheader = "&g";
                //将显示模式设置为layout
                sheet.viewmode = viewmode.layout;
            }
            workbook.savetofile("result.xlsx", excelversion.version2010);
            system.diagnostics.process.start("result.xlsx");
        }
        private static system.drawing.image drawtext(string text, system.drawing.font font, color textcolor, color backcolor, double height, double width)
        {
            //定义图片宽度和告诉
            image img = new bitmap((int)width, (int)height);
            graphics drawing = graphics.fromimage(img);
            //获取文本size
            sizef textsize = drawing.measurestring(text, font);
            //文本显示样式及位置
            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);
            drawing.clear(backcolor);
            brush textbrush = new solidbrush(textcolor);
            drawing.drawstring(text, font, textbrush, ((int)width - textsize.width) / 2, ((int)height - textsize.height) / 2);
            drawing.save();
            return img;
        }
    }
}

imports spire.xls
imports system.drawing
namespace addwatermarktoexcel
	class program
		private shared sub main(args as string())
			'加载示例文档
			dim workbook as new workbook()
			workbook.loadfromfile("sample.xlsx")
			'设置文本和字体大小
			dim font as font = new system.drawing.font("仿宋", 40)
			dim watermark as [string] = "内部文档"
			for each sheet as worksheet in workbook.worksheets
				'调用drawtext() 方法插入图片
				dim imgwtrmrk as system.drawing.image = drawtext(watermark, font, system.drawing.color.lightcoral, system.drawing.color.white, sheet.pagesetup.pageheight, sheet.pagesetup.pagewidth)
				'将图片设置为页眉
				sheet.pagesetup.leftheaderimage = imgwtrmrk
				sheet.pagesetup.leftheader = "&g"
				'将显示模式设置为layout
				sheet.viewmode = viewmode.layout
			next
			workbook.savetofile("result.xlsx", excelversion.version2010)
			system.diagnostics.process.start("result.xlsx")
		end sub
		private shared function drawtext(text as [string], font as system.drawing.font, textcolor as color, backcolor as color, height as double, width as double) as system.drawing.image
			'定义图片宽度和告诉
			dim img as image = new bitmap(cint(width), cint(height))
			dim drawing as graphics = graphics.fromimage(img)
			'获取文本size
			dim textsize as sizef = drawing.measurestring(text, font)
			'文本显示样式及位置
			drawing.translatetransform((cint(width) - textsize.width) / 2, (cint(height) - textsize.height) / 2)
			drawing.rotatetransform(-45)
			drawing.translatetransform(-(cint(width) - textsize.width) / 2, -(cint(height) - textsize.height) / 2)
			drawing.clear(backcolor)
			dim textbrush as brush = new solidbrush(textcolor)
			drawing.drawstring(text, font, textbrush, (cint(width) - textsize.width) / 2, (cint(height) - textsize.height) / 2)
			drawing.save()
			return img
		end function
	end class
end namespace