public override int GetHashCode()
{
if(calcHashCode)
{
int prime = 31;
_hash_code = 1;
_hash_code = prime * _hash_code + ((FileName == null) ? 0 : FileName.GetHashCode());
_hash_code = prime * _hash_code + StartLine;
_hash_code = prime * _hash_code + EndLine;
_hash_code = prime * _hash_code + StartColumn;
_hash_code = prime * _hash_code + EndColumn;
calcHashCode = false;
}
return _hash_code;
}