/// <summary>
/// 从HTTP上下文的名称值对中装载数据到对象
/// <remarks>
/// <para>需要将名称值对中的值(string类型)转型为对象属性的类型，当前对象属性的类型只支持：</para>
/// <para>1.string</para>
/// <para>2.值类型(基础值类型+GUID+Enum)</para>
/// <para>3.可空值类型</para>
/// <para>如果不是以上类型，则会抛出转型无效的异常</para>
/// </remarks>
/// </summary>
/// <typeparam name="T">T必须是一个类，而且必须带有无参构造函数</typeparam>
/// <param name="pDataes">数据集</param>
/// <param name="pPropertyNameMapping">属性名映射</param>
/// <param name="pInstance">T实例,如果实例为null则自动创建一个T实例</param>
/// <returns></returns>
public static T LoadFrom <T>(NameValueCollection pDataes, IPropertyNameMapping pPropertyNameMapping, T pInstance = null) where T : class, new()
{
//参数处理
if (pPropertyNameMapping == null)
{
throw new ArgumentNullException("pPropertyNameMapping");
}
if (pDataes == null)
{
return(null);
}
//
Type tType = typeof(T);
if (pInstance == null)
{
pInstance = (T)Activator.CreateInstance(tType);
}
//获取需要进行数据赋值的属性设置器
foreach (string key in pDataes.Keys)
{
var propertyName = pPropertyNameMapping.GetPropertyNameBy(key);
if (!string.IsNullOrEmpty(propertyName))//存在属性映射
{
var propertyInfo = tType.GetProperty(propertyName);
if (propertyInfo != null)//对象中存在指定名称的属性
{
var setter = DynamicMethodFactory.CreatePropertySetter(propertyInfo);
if (setter != null) //属性存在设置器
{
var value = pDataes[key];
try
{
setter(pInstance, value.ChangeTypeTo(propertyInfo.PropertyType));
}
catch (Exception ex)
{
string errorMessage = string.Format("DataLoader设置值失败,数据键名[{0}],值[{1}].内部错误:[{2}]", key, value, ex.Message);
throw new ArgumentException(errorMessage, ex);
}
}
}
}
}
//返回值
return(pInstance);
}
/// <summary>
/// 从DataTable中装载数据到对象
/// </summary>
/// <typeparam name="T">T必须是一个类，而且必须带有无参构造函数</typeparam>
/// <param name="pDataes">数据集</param>
/// <param name="pPropertyNameMapping">属性名映射</param>
/// <returns>T数组</returns>
public static T[] LoadFrom <T>(DataTable pDataes, IPropertyNameMapping pPropertyNameMapping) where T : class, new()
{
//参数处理
if (pPropertyNameMapping == null)
{
throw new ArgumentNullException("pPropertyNameMapping");
}
if (pDataes == null)
{
return(null);
}
if (pDataes.Rows.Count <= 0)
{
return(new T[0]);
}
//
Type tType = typeof(T);
List <T> list = new List <T>();
Dictionary <string, SetValueDelegate> propertySetters = new Dictionary <string, SetValueDelegate>();
//获取需要进行数据赋值的属性设置器
foreach (DataColumn column in pDataes.Columns)
{
var columnName = column.ColumnName;
var propertyName = pPropertyNameMapping.GetPropertyNameBy(columnName);
if (!string.IsNullOrEmpty(propertyName))
{
var propertyInfo = tType.GetProperty(columnName);
if (propertyInfo != null)
{
var setter = DynamicMethodFactory.CreatePropertySetter(propertyInfo);
if (setter != null)
{
propertySetters.Add(columnName, setter);
}
}
}
}
//将数据从DataTable中装载到T中
foreach (DataRow dr in pDataes.Rows)
{
//创建实例
T t = (T)Activator.CreateInstance(tType);
//给实例赋值
foreach (var item in propertySetters)
{
var setter = item.Value;
try
{
if (dr[item.Key] != DBNull.Value)
{
setter(t, dr[item.Key]);
}
//else
//{
// setter(t, null);
//}
}
catch (Exception ex)
{
string errorMessage = string.Format("DataLoader设置值失败,数据列名[{0}],值[{1}].内部错误:[{2}]", item.Key, item.Value, ex.Message);
throw new ArgumentException(errorMessage, ex);
}
}
//将实例添加进结果集
list.Add(t);
}
//返回结果
return(list.ToArray());
}
