title: Comparing two PDF file in C#
body: <p>I have two pdf files and I want to compare those two pdf files and print the difference in messagebox.</p>
  
  <p>So far I have this (but it is not working as I expect):</p>
  
  <pre><code>  private void button1_Click(object sender, EventArgs e)
      {
          string str1 = this.textBox1.Text;
          string str2 = this.textBox2.Text;
  
          string comparison = str1.Replace(str2,"");
          MessageBox.Show(comparison);
      }
  
  
   private void ParsePDF(string filePath)
      {
          string text = string.Empty;
  
          PdfReader reader = new iTextSharp.text.pdf.PdfReader(filePath);
          byte[] streamBytes = reader.GetPageContent(1);
          PRTokeniser tokenizer = new PRTokeniser(streamBytes);
  
          while (tokenizer.NextToken())
          {
              if (tokenizer.TokenType == PRTokeniser.TokType.STRING)
              {
                  text += tokenizer.StringValue;
              }
          }
          this.textBox1.Text = text.ToString();
          this.textBox2.Text = text.ToString();
      }
  
  }
  </code></pre>
  
  <p>and just below I call that method: ParsePDF("C://Users//lf222aw//Desktop//file1.pdf");</p>
  
  <p>my program works like this:
  Suppose i have one textbox with text "I love stackoverflow" and the other textbox 
  "I stackoverflow" and my program prints this as a result: "I love stackoverflow" and what i want to print is "love" as a difference between two those files</p>
  
  <p>Any idea??
  Regards,</p>