c# - deserialize XML file into a list error -

i writed follow generic code deserialize xml file list:

public list<t> getlist<t>(string fpath) {      filestream fs;     fs = new filestream(fpath, filemode.open);     list<t> list;     xmlserializer xmls = new xmlserializer(typeof(list<t>));     list = (list<t>)xmls.deserialize(fs);     fs.close();     return list; } 

but got the exception on desirialize action.

"an exception of type system.invalidoperationexception occurred in system.xml.dll not handled in user code"

this example xml file:

<?xml version="1.0"?> <arrayofadmin xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"    xmlns:xsd="http://www.w3.org/2001/xmlschema">   <admin>     <myusername>user</myusername>     <mypassword>pass</mypassword>   </admin> </arrayofadmin> 

whats cause exception?

first of all, file should contain valid xml data serialized list<t> object. e.g. if have serialized list of integers items 1 , 2 xml should way:

<?xml version="1.0"?> <arrayofint xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"             xmlns:xsd="http://www.w3.org/2001/xmlschema">   <int>1</int>   <int>2</int> </arrayofint> 

or custom type:

<arrayofperson xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"                 xmlns:xsd="http://www.w3.org/2001/xmlschema">   <person>     <id>1</id>     <name>bob</name>   </person>   <person>     <id>2</id>     <name>joe</name>   </person> </arrayofperson> 

when file empty or has invalid data invalidoperationexception during deserialization attempt. read property message of exception details. e.g. if file empty, root element missing.

note: when working unmanaged resources it's better use using construct close/dispose such resources correctly in case of exception.

using (var stream = file.open(fpath, filemode.open)) {     var serializer = new xmlserializer(typeof(list<t>));     return (list<t>)serializer.deserialize(stream); }