C#

static void Main(string[] args)
{
    MemoryStream MemoryStream1 = new MemoryStream();
    StreamWriter StreamWriter1 = new StreamWriter(MemoryStream1);
    XmlTextWriter XMLWriter1 = new XmlTextWriter(StreamWriter1);

    XMLWriter1.WriteStartDocument();

    XMLWriter1.WriteStartElement("Entity");  //root element
    XMLWriter1.WriteAttributeString("node", "Hello Node");

    //root ending
    XMLWriter1.WriteEndElement();
    XMLWriter1.WriteEndDocument();

    //flush the buffer to underlying stream
    XMLWriter1.Flush();

    string content = Encoding.UTF8.GetString(MemoryStream1.GetBuffer());

    return;

}

class A
{
string abc = "";// at class level.
...//some variables
...
...
}

class B
{
A obj = new A();
obj.abc = "Value";
}

class C
{
A obj = new A();
}