compare two near duplicate documents(pdf files) in c#

private bool FileCompare(string file1, string file2)
{
int file1byte;
int file2byte;
FileStream fs1;
FileStream fs2;
 
// Determine if the same file was referenced two times.
if (file1 == file2)
{
// Return true to indicate that the files are the same.
return true;
}
 
// Open the two files.
fs1 = new FileStream(file1, FileMode.Open);
fs2 = new FileStream(file2, FileMode.Open);
 
// Check the file sizes. If they are not the same, the files 
// are not the same.
if (fs1.Length != fs2.Length)
{
// Close the file
fs1.Close();
fs2.Close();
 
// Return false to indicate files are different
return false;
}
 
// Read and compare a byte from each file until either a
// non-matching set of bytes is found or until the end of
// file1 is reached.
do
{
// Read one byte from each file.
file1byte = fs1.ReadByte();
file2byte = fs2.ReadByte();
}
while ((file1byte == file2byte) && (file1byte != -1));
 
// Close the files.
fs1.Close();
fs2.Close();
 
// Return the success of the comparison. "file1byte" is 
// equal to "file2byte" at this point only if the files are 
// the same.
return ((file1byte - file2byte) == 0);
}
 
private void PdfCompare_Load(object sender, EventArgs e)
{
 
}
 
private void button1_Click(object sender, EventArgs e)
{
if (FileCompare(this.textBox1.Text, this.textBox2.Text))
{
MessageBox.Show("Files are equal.");
}
else
{
MessageBox.Show("Files are not equal.");
} 
}
 
}