/// <summary>
/// 根据关系属性构造查询表达式。
/// </summary>
/// <param name="entity"></param>
/// <param name="relationProperty"></param>
/// <param name="thisKey"></param>
/// <param name="otherKey"></param>
/// <returns></returns>
protected virtual Expression BuildRelationExpression(IEntity entity, RelationProperty relationProperty, Func <RelationshipKey, IProperty> thisKey, Func <RelationshipKey, IProperty> otherKey)
{
var relationKey = RelationshipUnity.GetRelationship(relationProperty);
if (relationKey == null)
{
return(null);
}
var parExp = Expression.Parameter(relationProperty.RelationType, "s");
Expression binExp = null;
foreach (var key in relationKey.Keys)
{
var val = entity.InternalGetValue(thisKey(key));
if (PropertyValue.IsNullOrEmpty(val) || !val.IsValid)
{
continue;
}
var member = otherKey(key).Info.ReflectionInfo;
var mbrExp = Expression.MakeMemberAccess(parExp, member);
var exp = Expression.Equal(mbrExp, Expression.Constant(val.GetStorageValue()));
binExp = binExp == null ? exp : Expression.And(binExp, exp);
}
if (binExp == null)
{
return(null);
}
return(Expression.Lambda(binExp, parExp));
}
/// <summary>
/// 创建关联查询的表达式。
/// </summary>
/// <param name="entity"></param>
/// <param name="relationProperty"></param>
/// <returns></returns>
private Expression BuidRelationExpression(IEntity entity, RelationProperty relationProperty)
{
return(BuildRelationExpression(entity, relationProperty,
new Func <RelationshipKey, IProperty>(k => k.OtherProperty),
new Func <RelationshipKey, IProperty>(k => k.ThisProperty)));
}