静态对象线程安全

Question

I have a pre-loaded static xmldocument object which has errorcode and it descriptions, If i am using multi threaded application and trying to get a error code description for particular error code, Do i need to put a lock on that method or not.

Here is my code in brief (Pls. ignore the implementation of GetErrorCodeDescription method, Only consider that _oXmlDoc has been used ),

Pre-loaded static xmldocument _oXmlDoc

later i am calling GetErrorCodeDescription method to get an error code description like this ,

Public string GetErrorCodeDescription(string errorCode)
{
string errorDEscption="";

    XmlNodeList elemList = **_oXmlDoc**.GetElementsByTagName(errorCode);

    for (int i=0; i < elemList.Count; i++)
    {   
      errorDEscption=elemList[i].InnerXml);
    }  

return errorDEscption;

}

Answer 1

You would be better off doing this parsing of XML just once and putting all error codes and corresponding descriptions into a dictionary. If you use ConcurrentDictionary for this, you should be safe.

Answer 2

From the XmlDocument docs ;

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

So, no, use of your static instance is not guaranteed to be thread safe without locking.