C# Type.Type.IsAssignableFrom方法代碼示例

		internal object CoerceType(Type targetType, object value)
		{
			bool isNullable = TypeCoercionUtility.IsNullable(targetType);
			if (value == null)
			{
				if (!allowNullValueTypes &&
					targetType.IsValueType &&
					!isNullable)
				{
					throw new JsonTypeCoercionException(String.Format(TypeCoercionUtility.ErrorNullValueType, targetType.FullName));
				}
				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 (value is String)
				{
					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;
							}
						}
					}

					return Enum.Parse(targetType, (string)value);
				}
				else
				{
					value = this.CoerceType(Enum.GetUnderlyingType(targetType), value);
					return Enum.ToObject(targetType, value);
				}
			}

			if (value is IDictionary)
			{
				Dictionary<string, MemberInfo> memberMap;
				return this.CoerceType(targetType, (IDictionary)value, out memberMap);
			}

			if (typeof(IEnumerable).IsAssignableFrom(targetType) &&
				typeof(IEnumerable).IsAssignableFrom(actualType))
			{
				return this.CoerceList(targetType, actualType, (IEnumerable)value);
			}

			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(Char))
				{
					if (((string)value).Length == 1)
					{
						return ((string)value)[0];
					}
				}
				else if (targetType == typeof(Uri))
				{
					Uri uri;
					if (Uri.TryCreate((string)value, UriKind.RelativeOrAbsolute, out uri))
					{
//.........這裏部分代碼省略.........

		internal bool IsAssignableTo (Type c)
		{
			if (c == this)
				return true;

			if (c.IsInterface) {
				if (parent != null && is_created) {
					if (c.IsAssignableFrom (parent))
						return true;
				}

				if (interfaces == null)
					return false;
				foreach (Type t in interfaces)
					if (c.IsAssignableFrom (t))
						return true;
				if (!is_created)
					return false;
			}

			if (parent == null)
				return c == typeof (object);
			else
				return c.IsAssignableFrom (parent);
		}