C#利用iTextSharp添加PDF水印

本文实例为大家分享了使用的是itextsharp添加pdf水印的具体代码，供大家参考，具体内容如下

需要itextsharp.dll, 下载地址

public void test()
    {
      watermark(@"e:\日常工作\12084347 config.pdf", @"e:\日常工作\12084347 config wm.pdf", @"e:\日常工作\wm.png");
}    

 public bool addwatermark(string inputpath, string outputpath, string watermarkpath, ref string error)
    {
      try
      {
        pdfreader pdfreader = new pdfreader(inputpath);
        int numberofpages = pdfreader.numberofpages;
        filestream outputstream = new filestream(outputpath, filemode.create);
        pdfstamper pdfstamper = new pdfstamper(pdfreader, outputstream);
        pdfcontentbyte watermarkcontent;

        itextsharp.text.image image = null;
        if (string.isnullorempty(watermarkpath))
        {
          stream s = gettype().assembly.getmanifestresourcestream("watermarktool.wm.png");
          image = itextsharp.text.image.getinstance(s);
        }
        else
        {
          image = itextsharp.text.image.getinstance(watermarkpath);
        }        
        image.setabsoluteposition(100, 100);
        for (int i = 1; i <= numberofpages; i++)
        {
          watermarkcontent = pdfstamper.getundercontent(i);
          watermarkcontent.addimage(image);
        }
        pdfstamper.close();
        pdfreader.close();
        outputstream.close();
        return true;
      }
      catch (exception ex)
      {
        error = ex.stacktrace;
        return false;
      }
    }

 //选择文件夹
    private void textbox2_doubleclick(object sender, eventargs e)
    {
      folderbrowserdialog dialog = new folderbrowserdialog();
      dialog.description = label2.text;
      if (dialog.showdialog() == dialogresult.ok)
      {
        textbox2.text = dialog.selectedpath;
      }
    }

    //选择文件
    private void textbox3_doubleclick(object sender, eventargs e)
    {
      openfiledialog filedialog = new openfiledialog();
      filedialog.multiselect = true;
      filedialog.title = label3.text;
      filedialog.filter = "*.jpg|*.jpg|*.jpeg|*.jpeg|*.bmp|*.bmp|*.gif|*.gif|*.png|*.png|*.tiff|*.tiff|*.wmf|*.wmf";
      if (filedialog.showdialog() == dialogresult.ok)
      {
        textbox3.text = filedialog.filename;
      }
    }

 //启动线程
    private void button1_click(object sender, eventargs e)
    {
      if (directory.exists(textbox1.text) == false )
      {
        messagebox.show(label1.text, "require input", messageboxbuttons.ok, messageboxicon.warning);
        textbox1.focus();
        return;
      }
      if (directory.exists(textbox2.text) == false)
      {
        messagebox.show(label2.text, "require input", messageboxbuttons.ok, messageboxicon.warning);
        textbox2.focus();
        return;
      }
      if ( textbox3.enabled && file.exists(textbox3.text) == false)
      {
        messagebox.show(label3.text, "require input", messageboxbuttons.ok, messageboxicon.warning);
        textbox3.focus();
        return;
      }

      richtextbox1.clear();
      button1.enabled = false;
      thread thread = new thread(new threadstart(this.batchdo));

      thread.isbackground = true;
      thread.start(); 
    }

 public delegate void setcontrolvalue(string message);
    //在线程中修改控件属性
    public void appendrtbtext(string text)
    {
      if (richtextbox1.invokerequired)
      {
        setcontrolvalue cal = delegate(string s) { richtextbox1.appendtext(s); };
        this.invoke(cal, text);
      }
      else
      {
        richtextbox1.appendtext(text);
      }
    }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。