資料處理 - 資料庫欄位及物件屬性映射類別

來源

ASP.NET Starter Kits 的 Portal 專案。

 

用途

以泛型集合為中介，做資料庫欄位及物件屬性之映射。

 

原始碼

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Reflection;


namespace SybaseUtility
{
    public static class DataMapper
    {
        public static void SetPropertyValue(object target, string propertyName, object value)
        {
            PropertyInfo propertyInfo = target.GetType().GetProperty(propertyName);

            if (value == null)
                propertyInfo.SetValue(target, value, null);
            else
            {
                Type pType = GetPropertyType(propertyInfo.PropertyType);
                Type vType = GetPropertyType(value.GetType());

                if (pType.Equals(vType))
                {
                    // types match, just copy value
                    propertyInfo.SetValue(target, value, null);
                }
                else
                {
                    // types don't match, try to coerce
                    if (pType.Equals(typeof(Guid)))
                        propertyInfo.SetValue(target, new Guid(value.ToString()), null);
                    else if (pType.IsEnum && vType.Equals(typeof(string)))
                        propertyInfo.SetValue(target, Enum.Parse(pType, value.ToString()), null);
                    else
                        propertyInfo.SetValue(target, Convert.ChangeType(value, pType), null);
                }
            }
        }

        public static PropertyInfo[] GetSourceProperties(Type sourceType)
        {
            List<PropertyInfo> result = new List<PropertyInfo>();
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(sourceType);

            foreach (PropertyDescriptor item in props)
                if (item.IsBrowsable)
                    result.Add(sourceType.GetProperty(item.Name));
            return result.ToArray();
        }

        /// <summary>
        /// Returns a property's type, dealing with
        /// Nullable(Of T) if necessary.
        /// </summary>
        /// <param name="propertyType">Type of the
        /// property as returned by reflection.</param>
        private static Type GetPropertyType(Type propertyType)
        {
            Type type = propertyType;
            if (type.IsGenericType && (type.GetGenericTypeDefinition() == typeof(Nullable<>)))
                return Nullable.GetUnderlyingType(type);
            return type;
        }
    }
}