System.Xml.Serialization.XmlCodeExporter.ImportDefaultValue C# (CSharp) Method

        object ImportDefaultValue(TypeMapping mapping, string defaultValue) {
            if (defaultValue == null)
                return null;
            if (!(mapping is PrimitiveMapping))
                return DBNull.Value;

            if (mapping is EnumMapping) {
                EnumMapping em = (EnumMapping)mapping;
                ConstantMapping[] c = em.Constants;

                if (em.IsFlags) {
                    Hashtable values = new Hashtable();
                    string[] names = new string[c.Length];
                    long[] ids = new long[c.Length];

                    for (int i = 0; i < c.Length; i++) {
                        ids[i] = em.IsFlags ? 1L << i : (long)i;
                        names[i] = c[i].Name;
                        values.Add(c[i].XmlName, ids[i]);
                    }
                    // this validates the values
                    long val = XmlCustomFormatter.ToEnum(defaultValue, values, em.TypeName, true);
                    return XmlCustomFormatter.FromEnum(val, names, ids, em.TypeDesc.FullName);
                }
                else {
                    for (int i = 0; i < c.Length; i++) {
                        if (c[i].XmlName == defaultValue)
                            return c[i].Name;
                    }
                }
                throw new InvalidOperationException(Res.GetString(Res.XmlInvalidDefaultValue, defaultValue, em.TypeDesc.FullName));
            }

            // Primitive mapping
            PrimitiveMapping pm = (PrimitiveMapping)mapping;

            if (!pm.TypeDesc.HasCustomFormatter) {
                if (pm.TypeDesc.FormatterName == "String")
                    return defaultValue;
                if (pm.TypeDesc.FormatterName == "DateTime")
                    return XmlCustomFormatter.ToDateTime(defaultValue);

                Type formatter = typeof(XmlConvert);

                MethodInfo format = formatter.GetMethod("To" + pm.TypeDesc.FormatterName, new Type[] {typeof(string)});
                if (format != null) {
                    return format.Invoke(formatter, new Object[] {defaultValue});
                }
#if DEBUG
                Debug.WriteLineIf(DiagnosticsSwitches.XmlSerialization.TraceVerbose, "XmlSerialization::Failed to GetMethod " + formatter.Name + ".To" + pm.TypeDesc.FormatterName);
#endif
            }
            else {
                if (pm.TypeDesc.HasDefaultSupport) {
                    return XmlCustomFormatter.ToDefaultValue(defaultValue, pm.TypeDesc.FormatterName);
                }
            }
            return DBNull.Value;
        }