private static object CoerceType(Type targetType, object value, int index, bool allowNullValueTypes)
{
bool isNullable = JsonReader.IsNullable(targetType);
if (value == null)
{
if (allowNullValueTypes &&
targetType.IsValueType &&
!isNullable)
{
throw new JsonDeserializationException(String.Format(JsonReader.ErrorNullValueType, targetType.FullName), index);
}
return(value);
}
if (isNullable)
{
// nullable types have a real underlying struct
Type[] genericArgs = targetType.GetGenericArguments();
if (genericArgs.Length == 1)
{
targetType = genericArgs[0];
}
}
Type actualType = value.GetType();
if (targetType.IsAssignableFrom(actualType))
{
return(value);
}
if (targetType.IsEnum)
{
if (!Enum.IsDefined(targetType, value))
{
// if isn't a defined value perhaps it is the JsonName
foreach (FieldInfo field in targetType.GetFields())
{
string jsonName = JsonNameAttribute.GetJsonName(field);
if (((string)value).Equals(jsonName))
{
value = field.Name;
break;
}
}
}
if (value is String)
{
return(Enum.Parse(targetType, (string)value));
}
else
{
return(Convert.ChangeType(value, targetType));
}
}
if (actualType.IsArray && !targetType.IsArray)
{
return(JsonReader.CoerceArray(targetType, actualType, value, index, allowNullValueTypes));
}
if (value is String)
{
if (targetType == typeof(DateTime))
{
DateTime date;
if (DateTime.TryParse(
(string)value,
DateTimeFormatInfo.InvariantInfo,
DateTimeStyles.RoundtripKind | DateTimeStyles.AllowWhiteSpaces | DateTimeStyles.NoCurrentDateDefault,
out date))
{
return(date);
}
}
else if (targetType == typeof(Guid))
{
// try-catch is pointless since will throw upon generic conversion
return(new Guid((string)value));
}
else if (targetType == typeof(Uri))
{
Uri uri;
if (Uri.TryCreate((string)value, UriKind.RelativeOrAbsolute, out uri))
{
return(uri);
}
}
else if (targetType == typeof(Version))
{
// try-catch is pointless since will throw upon generic conversion
return(new Version((string)value));
}
}
else if (targetType == typeof(TimeSpan))
{
return(new TimeSpan((long)JsonReader.CoerceType(typeof(Int64), value, index, allowNullValueTypes)));
}
TypeConverter converter = TypeDescriptor.GetConverter(targetType);
if (converter.CanConvertFrom(actualType))
{
return(converter.ConvertFrom(value));
}
converter = TypeDescriptor.GetConverter(actualType);
if (converter.CanConvertTo(targetType))
{
return(converter.ConvertTo(value, targetType));
}
return(Convert.ChangeType(value, targetType));
}