/// <summary>
/// Query IEnumerable<T> by sql
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="context"></param>
/// <param name="sql"></param>
/// <param name="args"></param>
/// <returns></returns>
public static IEnumerable <T> Query <T>(this IRepositoryContext context, string sql, params object[] args)
where T : new()
{
using (var dr = context.ExecuteDataReader(sql)) {
if (dr.HasRows)
{
var propCache = new Dictionary <string, PropertyInfo>();
var drFields = new List <string>();
for (var i = 0; i < dr.FieldCount; i++)
{
drFields.Add(dr.GetName(i));
}
while (dr.Read())
{
var insT = new T();
if (propCache.Count == drFields.Count)
{
var propList = insT.GetType().GetProperties();
foreach (var field in drFields)
{
var prop = propCache[field];
var value = dr[field];
if (value != DBNull.Value)
{
prop.SetValue(insT, value, null);
}
}
}
else
{
var propList = insT.GetType().GetProperties();
foreach (var prop in propList)
{
var field = prop.Name;
if (!drFields.Contains(field))
{
continue;
}
if (!prop.CanWrite)
{
continue;
}
var value = dr[field];
if (value != DBNull.Value)
{
prop.SetValue(insT, value, null);
}
if (!propCache.ContainsKey(field))
{
propCache.Add(field, prop);
}
}
// Re-balance PropCache & drFields
if (propCache.Count != drFields.Count)
{
var interset = drFields.Intersect(propCache.Select(x => x.Key)).ToList();
drFields = interset;
var subSet = propCache.Select(x => x.Key).Except(interset);
foreach (var item in subSet)
{
propCache.Remove(item);
}
}
}
yield return(insT);
}
}
}
}