紧接上一篇介绍DataHelper的用法。

    DataHelper在使用过程中最好的就配合BindObject类一起使用。下面附上BindObject类的源码：

BindObject
  1public class BindObject
  2    {
  3        绑定#region 绑定
  4        
  5        public static object[] BindObjectToArray(Type instanceType, IDataReader reader)
  6        {
  7            try
  8            {
  9                PropertyInfo [] properties = instanceType.GetProperties();
 10                ArrayList items = new ArrayList();
 11                Hashtable fieldName = new Hashtable();
 12                int fieldCount = reader.FieldCount;
 13                for (int i = 0; i < fieldCount; i++)
 14                {
 15                    string name = reader.GetName(i).ToString().ToLower();
 16                    fieldName.Add(name, i);
 17                }
 18                while (reader.Read())
 19                {
 20                    object instance = Activator.CreateInstance(instanceType);
 21                    foreach (PropertyInfo property in properties)
 22                    {
 23                        object[] attributes = property.GetCustomAttributes(typeof(MappingFieldAttribute), false);
 24                        object[] encoders = property.GetCustomAttributes(typeof(CharacterEncodeAttribute), false);
 25                        string aName = string.Empty;
 26                        CharacterEncodeAttribute encoder = null;
 27                        if(attributes != null && attributes.Length > 0)
 28                        {
 29                            MappingFieldAttribute mapping = attributes[0] as MappingFieldAttribute;
 30                            aName = mapping.FieldName.ToLower();
 31                        }
 32                        if (encoders != null && encoders.Length > 0)
 33                        {
 34                            encoder = encoders[0] as CharacterEncodeAttribute;
 35                        }
 36                        string pName = property.Name.Trim().ToLower();
 37                        int index = -1;
 38                        if (fieldName.ContainsKey(pName))
 39                            index = (int)fieldName[pName];
 40                        else if (aName != string.Empty && fieldName.ContainsKey(aName))
 41                            index = (int)fieldName[aName];
 42                        if (index >= 0)
 43                        {
 44                            object obj = reader[index];
 45                            Type propertyType = property.PropertyType;
 46                            if (propertyType.IsArray || propertyType.IsInterface)
 47                            {
 48                                continue;
 49                            }
 50                            else if (property.PropertyType.IsEnum)
 51                            {
 52                                if(obj != null && obj != DBNull.Value)
 53                                    property.SetValue(instance, Enum.Parse(property.PropertyType, obj.ToString(), true), null);
 54                            }
 55                            else
 56                            {
 57                                if(obj != null && obj != DBNull.Value)
 58                                {
 59                                    if(property.PropertyType == typeof(string) && encoder != null)
 60                                        property.SetValue(instance, encoder.Encode(obj.ToString()), null);
 61                                    else
 62                                        property.SetValue(instance, Convert.ChangeType(obj, property.PropertyType), null);
 63                                }                                 
 67                            }
 68                        }
 69                    }
 70                    items.Add(instance);
 71                }
 72                if (!reader.IsClosed)
 73                    reader.Close();
 74                object [] instances = (object[])Array.CreateInstance(instanceType, items.Count);
 75                for(int i = 0; i < items.Count; i++)
 76                {
 77                    //string str=  "<![CDATA[" + items[i].ToString() +"]]>";
 78                    instances[i] = items[i];
 79                }
 80                return instances;
 81            }
 82            catch(Exception ex)
 83            {
 84                throw ex;
 85            }
 86        }
 87
 88        
 89        /**//// <summary>
 90        /// 绑定
 91        /// </summary>
 92        /// <param name="instanceType"></param>
 93        /// <param name="reader"></param>
 94        /// <returns></returns>
 95        public static IList BindObjectToInstance(Type instanceType, IDataReader reader)
 96        {
 97            PropertyInfo [] properties = instanceType.GetProperties(BindingFlags.Public | BindingFlags.Instance);
 98            ArrayList items = new ArrayList();
 99            Hashtable fieldName = new Hashtable();
            int fieldCount = reader.FieldCount;
            for (int i = 0; i < fieldCount; i++)
            {
                string name = reader.GetName(i).ToString().ToLower();
                fieldName.Add(name, i);
            }
            while (reader.Read())
            {
                object instance = Activator.CreateInstance(instanceType);
                foreach (PropertyInfo property in properties)
                {
                    string pName = property.Name.Trim().ToLower();
                    int index = -1;
                    if (fieldName.ContainsKey(pName))
                        index = (int)fieldName[pName];
                    if (index >= 0)
                    {
                        object obj = reader[index];
                        Type propertyType = property.PropertyType;
                        if (propertyType.IsArray || propertyType.IsInterface)
                        {
                            continue;
                        }
                        else if (property.PropertyType.IsEnum)
                        {
                            if(obj != null && obj != DBNull.Value)
                                property.SetValue(instance, Enum.Parse(property.PropertyType, obj.ToString(), true), null);
                        }
                        else
                        {
                            if(obj != null && obj != DBNull.Value)
                                property.SetValue(instance, Convert.ChangeType(obj, property.PropertyType), null);
                        }
                    }
                }
                items.Add(instance);
            }
            if (!reader.IsClosed)
                reader.Close();
            return items;
        }
        #endregion
    }

下面再给出一个结合两者使用的方法：

Test(int id)
 1 public IList Test(int id)
 2        {
 3            using (DataHelper helper = new DataHelper("server=localhost;database=pubs;uid=sa;pwd=111;"))
 4            {
 5                IDataReader reader = helper.CreateQuery(@"Select * From Table1 Where id=:id")
 6                    .SetInt32("id", id)
 7                    .ExecuteReader();
 8                return BindObject.BindObjectToInstance(typeof(Table1), reader);
 9            }
        }

这个操作DataHelper的方法比较简单一看就明白我这里就不详细介绍了，简单的介绍下BindObject类，它是运用了反射的方式来对实体中的字段进行读取比较，然后赋值的，所以实体中的字段必须对应我们所写sql中的列。
个人觉得这些都没啥技术含量，其实真正重要是思想，是一种解决问题的方法。
注：这里的BindObject类里还涉及到自定义属性的问题，直接拷贝进去是运行不了，在下篇里将继续附上该类代码。并介绍其用处。呵呵。。。
本人水平有限，希望能迎来大家的“砖头”，越多越好咯。。。