XmlDocument xmlDoc = new XmlDocument();xmlDoc.Load(responsedata);
It's give exception: System.UriFormatException: Invalid URI: The Uri string is too long.
XmlDocument xmlDoc = new XmlDocument();xmlDoc.Load(responsedata);
It's give exception: System.UriFormatException: Invalid URI: The Uri string is too long.
xmlDoc.Load expects a URL not the file itsself. That's why it is telling that. It expects a normal URI but you hand it a big file...
http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.load.aspx
I believe there is an assumption that responsedata holds a value pointing to an xml file to read in, i.e. "c:\temp\sometest.xml".
From your case, however, it appears that the responedata is a stream you received from a Web Service request. If this is the case, the try the following:
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(responsedata);
HTH