/// <summary>
/// 删除对象
/// </summary>
/// <param name="uuid"></param>
/// <returns></returns>
public bool Delete(Guid uuid)
{
TreeviewContext context = new TreeviewContext();
var dataSource = context.TreeNodeSource;
var oldObj = dataSource.FirstOrDefault(o => o.UUID == uuid);
if (oldObj == null)
{
return(true);
}
List <Guid> needDeleteUUIDs = new List <Guid>();
if (HasChildren(uuid, ref context))
{
GetDeleteChildren(uuid, ref context, ref needDeleteUUIDs);
if (needDeleteUUIDs.Count > 0)
{
foreach (var id in needDeleteUUIDs)
{
var tempObj = dataSource.FirstOrDefault(o => o.UUID == id);
if (tempObj == null)
{
continue;
}
dataSource.Remove(tempObj);
}
}
}
dataSource.Remove(oldObj);
if (context.SaveChanges() > 0)
{
return(true);
}
return(true);
}
/// <summary>
/// 通过一个新的对象来更新旧对象,
/// 具体做法是将新对象中的属性的
/// 值全部复制到旧对象中更新
/// </summary>
/// <param name="newobj"></param>
/// <returns></returns>
public static TEntity Update(TEntity newobj)
{
TreeviewContext context = new TreeviewContext();
var oldObj = context.GetDatasource <TEntity>().FirstOrDefault(o => o.UUID == newobj.UUID);
if (oldObj == null)
{
throw new Exception("未找到需要更新的元素");
}
Common.UpdateObj(ref oldObj, newobj);
if (context.SaveChanges() > 0)
{
return(newobj);
}
return(null);
}
/// <summary>
/// 删除一个元素,如果元素不存在,则直接返回true
/// </summary>
/// <param name="uuid"></param>
/// <returns>
/// 如果元素不存在,返回true
/// 删除成功返回true
/// 如果删除失败,则返回false
/// </returns>
public static bool Delete(Guid uuid)
{
TreeviewContext context = new TreeviewContext();
var dataSource = context.GetDatasource <TEntity>();
var oldObj = dataSource.FirstOrDefault(o => o.UUID == uuid);
if (oldObj == null)
{
return(true);
}
dataSource.Remove(oldObj);
if (context.SaveChanges() > 0)
{
return(true);
}
return(true);
}
/// <summary>
/// 添加一个新的对象,并且该函数会给对象自动赋予UUID,
/// 如果外部已经有生成一个UUID,执行该函数后UUID会
/// 被重写,如果数据插入成功,将返回该对象,如果出错,那么
/// 则返回一个空对象.
/// </summary>
/// <param name="e"></param>
/// <returns></returns>
public static TEntity Add(TEntity e)
{
if (Exists(e))
{
throw new EntityExistsException("Entity has exists.");
}
if (e.UUID == Guid.Empty)
{
e.UUID = Guid.NewGuid();
}
TreeviewContext context = new TreeviewContext();
context.GetDatasource <TEntity>().Add(e);
int flag = context.SaveChanges();
if (flag > 0)
{
return(e);
}
return(null);
}