Expression Tree

Expression Tree

Expression Tree 的一個例子

Expression Tree 的一個例子

public static class ObjectionExtension
    {
        /// <summary>
        /// 獲取屬性的名稱
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <typeparam name="TProperty">屬性</typeparam>
        /// <param name="t">對象</param>
        /// <param name="expression">屬性</param>
        /// <returns>屬性的名稱</returns>
        public static string GetPropertyName<T, TProperty>(this T t, Expression<Func<T, TProperty>> expression)
        {
            var memberExpression = expression.Body as MemberExpression;
            if (memberExpression != null)
            {
                return memberExpression.Member.Name;
            }
            var paramExpression = expression.Body as ParameterExpression;
            if (paramExpression != null)
            {
                return paramExpression.Name;
            }
            return string.Empty;
        }

        /// <summary>  
        /// 根據屬性名獲取屬性值  
        /// </summary>  
        /// <typeparam name="T">對象類型</typeparam>  
        /// <param name="t">對象</param>  
        /// <param name="name">屬性名</param>  
        /// <returns>屬性的值</returns>  
        public static TProperty GetPropertyValue<T, TProperty>(this T t, Expression<Func<T, TProperty>> expression)
        {
            var func = expression.Compile();
            var result = func(t);
            return result;
        }

        /// <summary>  
        /// 根據屬性名稱設置屬性的值  
        /// </summary>  
        /// <typeparam name="T">對象類型</typeparam>  
        /// <param name="t">對象</param>  
        /// <param name="name">屬性名</param>  
        /// <param name="value">屬性的值</param>  
        public static void SetPropertyValue<T>(this T t, Action<T> action)
        {
            action(t);
        }

        public static T As<T>(this object obj)
        {
            return default(T);
        }
    }