/// <summary>
/// 查询指定实体的孩子。
/// </summary>
/// <param name="entity">当前实体。</param>
/// <param name="predicate">用于测试每个元素是否满足条件的函数。</param>
/// <param name="recurrence">是否递归出所有孩子。</param>
/// <returns></returns>
public virtual IQueryable <TEntity> QueryChildren(TEntity entity, Expression <Func <TEntity, bool> > predicate = null, bool recurrence = false)
{
var expression = TreeExpressionBuilder.BuildQueryChildrenExpression(metaTree, entity, predicate, recurrence);
var querable = QueryHelper.CreateQuery <TEntity>(repository.Provider, expression);
var orderExp = TreeExpressionBuilder.BuildOrderByExpression <TEntity>(metaTree, querable.Expression);
return(repository.Provider.CreateQuery <TEntity>(orderExp));
}
/// <summary>
/// 获取孩子、孙子、重孙...。
/// </summary>
/// <param name="argument"></param>
/// <param name="isolation"></param>
/// <returns></returns>
private IEnumerable <TEntity> GetChildren(EntityTreeUpfydatingArgument argument, Expression <Func <TEntity> > isolation = null)
{
var expression = TreeExpressionBuilder.BuildGetChildrenExpression <TEntity>(metaTree, argument.OldValue.InnerId);
var querable = QueryHelper.CreateQuery <TEntity>(repository.Provider, expression);
expression = TreeExpressionBuilder.AddIsolationExpression <TEntity>(querable.Expression, isolation);
expression = TreeExpressionBuilder.AddUseableSelectExpression <TEntity>(metaTree, expression);
return(repository.Provider.CreateQuery <TEntity>(expression).ToList());
}
/// <summary>
/// 判断实体是否具有孩子。
/// </summary>
/// <param name="entity">当前实体。</param>
/// <param name="predicate">用于测试每个元素是否满足条件的函数。</param>
/// <returns></returns>
public virtual bool HasChildren(TEntity entity, Expression <Func <TEntity, bool> > predicate = null)
{
var query = (IQueryable)QueryHelper.CreateQuery <TEntity>(repository.Provider, predicate);
var mthCount = typeof(Enumerable).GetMethods().FirstOrDefault(s => s.Name == "Count" && s.GetParameters().Length == 2);
mthCount = mthCount.MakeGenericMethod(typeof(TEntity));
var expression = TreeExpressionBuilder.BuildHasChildrenExpression(metaTree, entity, predicate);
expression = Expression.Call(null, mthCount, query.Expression, expression);
return((int)repository.Provider.Execute(expression) > 0);
}
/// <summary>
/// 异步的，判断实体是否具有孩子。
/// </summary>
/// <param name="entity">当前实体。</param>
/// <param name="predicate">用于测试每个元素是否满足条件的函数。</param>
/// <param name="cancellationToken">取消操作的通知。</param>
/// <returns></returns>
public virtual async Task <bool> HasChildrenAsync(TEntity entity, Expression <Func <TEntity, bool> > predicate = null, CancellationToken cancellationToken = default)
{
var query = (IQueryable)QueryHelper.CreateQuery <TEntity>(repository.Provider, predicate);
var mthCount = typeof(Enumerable).GetMethods().FirstOrDefault(s => s.Name == "Count" && s.GetParameters().Length == 2);
mthCount = mthCount.MakeGenericMethod(typeof(TEntity));
var expression = TreeExpressionBuilder.BuildHasChildrenExpression(metaTree, entity, predicate);
expression = Expression.Call(null, mthCount, query.Expression, expression);
return(await((IAsyncQueryProvider)repository.Provider).ExecuteAsync <int>(expression, cancellationToken) > 0);
}
/// <summary>
/// 递归返回实体的父亲实体。
/// </summary>
/// <param name="entity">当前实体。</param>
/// <param name="predicate">用于测试每个元素是否满足条件的函数。</param>
/// <returns></returns>
public IQueryable <TEntity> RecurrenceParent(TEntity entity, Expression <Func <TEntity, bool> > predicate = null)
{
Guard.ArgumentNull(entity, nameof(entity));
var keyId = (string)entity.GetValue(metaTree.InnerSign);
var parents = new List <string>();
while ((keyId = keyId.Substring(0, keyId.Length - metaTree.SignLength)).Length > 0)
{
parents.Add(keyId);
}
var expression = TreeExpressionBuilder.BuildGetByInnerIdExpression <TEntity>(metaTree, predicate, parents);
var querable = QueryHelper.CreateQuery <TEntity>(repository.Provider, expression);
var orderExp = TreeExpressionBuilder.BuildOrderByLengthDescExpression <TEntity>(metaTree, querable.Expression);
return(repository.Provider.CreateQuery <TEntity>(orderExp));
}
/// <summary>
/// 查询指定实体的孩子。
/// </summary>
/// <param name="entity">当前实体。</param>
/// <param name="predicate">用于测试每个元素是否满足条件的函数。</param>
/// <param name="recurrence">是否递归出所有孩子。</param>
/// <returns></returns>
public virtual IQueryable <TEntity> QueryChildren(TEntity entity, Expression <Func <TEntity, bool> > predicate = null, bool recurrence = false)
{
var expression = TreeExpressionBuilder.BuildQueryChildrenExpression <TEntity>(GetMetadata(), entity, predicate, recurrence);
return(QueryHelper.CreateQuery <TEntity>(Provider, expression));
}
