I HATE doing monkey work and had the pleasure of such this afternoon.....
So herewith a switch statement that casts strings appropriatly for most SqlDbType type parameters.
string
{
prm.Value = Int64.Parse(nodeValue);
prm.Value = Boolean.Parse(nodeValue);
prm.Value = LeftStr(nodeValue,prm.Size);
prm.Value = DateTime.Parse(nodeValue);
prm.Value = Decimal.Parse(nodeValue);
prm.Value = Double.Parse(nodeValue);
prm.Value = Int32.Parse(nodeValue);
prm.Value = Single.Parse(nodeValue);
prm.Value = Int16.Parse(nodeValue);
prm.Value = nodeValue;
prm.Value = Byte.Parse(nodeValue);
prm.Value = Guid.NewGuid(nodeValue);
}