C#讀取對象實例的值和對對象的屬性自動賦值方法

using System;
using System.Data;
using System.Reflection;

namespace DBUtility
{
    /// <summary>
    /// 對象實例操作輔助類
    /// </summary>
    public static class InstanceHelper
    {
        /// <summary>
        /// 根據對象的屬性名稱，獲取屬性的值（用於根據對象自動完成參數化sql語句的賦值操作）
        /// </summary>
        /// <param name="propertyName">屬性名稱(忽略大小寫)</param>
        /// <param name="objectInstance">對象實例</param>
        /// <param name="objectType">對象實例類型</param>
        /// <returns>屬性的值</returns>
        public static object GetPropertyValue(string propertyName, object objectInstance, Type objectType)
        {
            PropertyInfo pi = objectType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
            if (pi == null)
                throw new ArgumentException("自動設置參數值失敗。參數化變量名稱" + propertyName + "必須和對象中的屬性名稱一樣。");
            if (!pi.CanRead)
                throw new ArgumentException("自動設置參數值失敗。對象的" + propertyName + "屬性沒有get方式，無法讀取值。");

            object value = pi.GetValue(objectInstance, null);
            if (value == null)
                value = DBNull.Value;
            else if (pi.PropertyType.Name == "DateTime" && Convert.ToDateTime(value) == DateTime.MinValue)
                value = DBNull.Value;//防止數據庫是smalldatetime類型時DateTime.MinValue溢出
            return value;
        }

        /// <summary>
        /// 將DataReader中的數據自動賦值到對象實例對應的屬性
        /// 注意：對象實例的屬性名稱必須和數據庫列名相同，可忽略大小寫
        /// </summary>
        /// <param name="dataReader">SqlDataReader等數據閱讀器獲取的一行數據</param>
        /// <param name="objectInstance">對象實例</param>
        /// <param name="objectType">對象實例類型</param>
        public static void SetPropertyValue(IDataReader dataReader, object objectInstance, Type objectType)
        {
            for (int i = 0; i < dataReader.FieldCount; i++)
            {
                PropertyInfo pi = objectType.GetProperty(dataReader.GetName(i), BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
                if (pi != null && pi.CanWrite && dataReader[i] != DBNull.Value)
                {
                    //如果是int?、bool?、double?等這種可空類型，獲取其實際類型，如int?的實際類型是int
                    Type baseType = Nullable.GetUnderlyingType(pi.PropertyType);
                    if (baseType != null)
                        pi.SetValue(objectInstance, Convert.ChangeType(dataReader[i], baseType), null);
                    else
                        pi.SetValue(objectInstance, Convert.ChangeType(dataReader[i], pi.PropertyType), null);//設置對象值
                }
            }
        }

        #region 用於Oracle數據庫操作

        /// <summary>
        /// 根據對象的屬性名稱，獲取屬性的值（用於根據對象自動完成參數化sql語句的賦值操作）
        /// </summary>
        /// <param name="propertyName">屬性名稱(忽略大小寫)</param>
        /// <param name="objectInstance">對象實例</param>
        /// <param name="objectType">對象實例類型</param>
        /// <returns>屬性的值</returns>
        public static object GetPropertyValue2(string propertyName, object objectInstance, Type objectType)
        {
            PropertyInfo pi = objectType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
            if (pi == null)
                throw new ArgumentException("自動設置參數值失敗。參數化變量名稱必須和對象中的屬性名稱一樣。");
            if (!pi.CanRead)
                throw new ArgumentException("自動設置參數值失敗。對象的" + propertyName + "屬性沒有get方式，無法讀取值。");

            object value = pi.GetValue(objectInstance, null);
            if (value == null)
                value = DBNull.Value;
            else if (pi.PropertyType.Name == "DateTime" && Convert.ToDateTime(value) == DateTime.MinValue)
                value = DBNull.Value;
            else if (pi.PropertyType.Name == "Boolean")//oracle數據庫用char(1)作為bool類型
                value = OraBit(Convert.ToBoolean(value));
            return value;
        }

        /// <summary>
        /// 將DataReader中的數據自動賦值到對象實例對應的屬性
        /// 注意：對象實例的屬性名稱必須和數據庫列名相同，可忽略大小寫
        /// </summary>
        /// <param name="dataReader">OracleDataReader獲取的一行數據</param>
        /// <param name="objectInstance">對象實例</param>
        /// <param name="objectType">對象實例類型</param>
        public static void SetPropertyValue2(IDataReader dataReader, object objectInstance, Type objectType)
        {
            for (int i = 0; i < dataReader.FieldCount; i++)
            {
                PropertyInfo pi = objectType.GetProperty(dataReader.GetName(i), BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
                if (pi != null && pi.CanWrite && dataReader[i] != DBNull.Value)
                {
                    Type baseType = Nullable.GetUnderlyingType(pi.PropertyType);//獲取其實際類型，如int?的實際類型是int                    
                    if (baseType != null)//如果是int?、bool?、double?等可空類型
                    {
                        if (baseType.Name == "Boolean")
                            pi.SetValue(objectInstance, OraBool(dataReader[i].ToString()), null);
                        else
                            pi.SetValue(objectInstance, Convert.ChangeType(dataReader[i], baseType), null);
                    }
                    else
                    {
                        if (pi.PropertyType.Name == "Boolean")
                            pi.SetValue(objectInstance, OraBool(dataReader[i].ToString()), null);
                        else
                            pi.SetValue(objectInstance, Convert.ChangeType(dataReader[i], pi.PropertyType), null);//設置對象值
                    }
                }
            }
        }

        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public static string OraBit(bool value)
        {
            if (value)
                return "Y";
            else
                return "N";
        }

        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public static bool OraBool(string value)
        {
            if (value.Equals("Y"))
                return true;
            else
                return false;
        }

        #endregion

    }
}

以上是通過反射對對象賦值，對對象賦值最高效方法是使用Emit，Emit對對象自動賦值如果加上緩存效率比手寫代碼效率更快。