System.Text.Encoding.GetDataItem C# (CSharp) Method

        private void GetDataItem() {
            if (dataItem==null) {
                dataItem = EncodingTable.GetCodePageDataItem(m_codePage);
                if(dataItem==null) {
                    throw new NotSupportedException(
                        Environment.GetResourceString("NotSupported_NoCodepageData", m_codePage));
                }
            }
        }