Compare and get Distinct elements from two XML files using C# .Net

Hi ,   I have two .xml files with contents as below:   demo1.xml ------------

<?xml version="1.0" encoding="ISO-8859-1"?>
<agenda>
    <Appointment>
      <Id> 7  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> test </Subject>
      <Description> testttt  </Description>
      <Place> paris  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>
    <Appointment>
      <Id> 8  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> whatever  </Subject>
      <Description> whateverrr  </Description>
      <Place> where ever  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>
</agenda>

  demo.xml -----------

<?xml version="1.0" encoding="ISO-8859-1"?>
<agenda>
    <Appointment>
      <Id> 7  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> test </Subject>
      <Description> testttt  </Description>
      <Place> paris  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>
</agenda>

  See from the two files above, Id=7 is common in both .xml files. I want to select Id=8 which is not present in demo.xml.   So my output should be as below:  

 <Appointment>
      <Id> 8  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> whatever  </Subject>
      <Description> whateverrr  </Description>
      <Place> where ever  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>
 

  I tried the below code but I could not arrive at what I need.  

string origPath = @"F:\demo.xml";
            string inPath = @"F:\demo1.xml";
            XElement xmlObject = XElement.Load(origPath);
            var xDoc = xmlObject.Descendants("Appointment");
            XElement xmlObject1 = XElement.Load(inPath);
            var xDoc1 = xmlObject1.Descendants("Appointment");
            var notIn = xDoc1.Except(xDoc);
            //var notIn1 = xDoc.Except(notIn);             foreach (XElement ele in notIn)
            {
                richTextBox1.AppendText(ele.ToString() + "\n");
                
            }

  When executing the code above I got:  

<Appointment>
      <Id> 7  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> test </Subject>
      <Description> testttt  </Description>
      <Place> paris  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>
    <Appointment>
      <Id> 8  </Id>
      <Date> 20060426  </Date>
      <Time> 120000  </Time>
      <Subject> whatever  </Subject>
      <Description> whateverrr  </Description>
      <Place> where ever  </Place>
      <Modtime> 182204  </Modtime>
    </Appointment>

  But the below code provides me the result what actually I need:

double[] numbers1 = { 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 };
double[] numbers2 = { 2.2 };
 
 IEnumerable<double> onlyInFirstSet = numbers1.Except(numbers2);
 
 foreach (double number in onlyInFirstSet)
    richTextBox1.AppendText(number.ToString() +"\n");
 

  The immediate above code provided: 2,2.1,2.3,2.4,2.5   Please let me know what is wrong in my code to fetch distinct elements from xml file?   BR, Arjun