public Expression ApplyNavigation(Expression source, IReadOnlyList <OeParseNavigationSegment> parseNavigationSegments)
{
if (parseNavigationSegments == null)
{
return(source);
}
Type sourceItemType = OeExpressionHelper.GetCollectionItemType(source.Type);
foreach (OeParseNavigationSegment parseNavigationSegment in parseNavigationSegments)
{
Type selectType;
ParameterExpression parameter;
Expression e;
if (parseNavigationSegment.NavigationSegment == null) //EntitySetSegment, KeySegment
{
parameter = Visitor.Parameter;
e = source;
selectType = sourceItemType;
}
else
{
parameter = Expression.Parameter(sourceItemType);
PropertyInfo navigationClrProperty = sourceItemType.GetProperty(parseNavigationSegment.NavigationSegment.NavigationProperty.Name);
e = Expression.MakeMemberAccess(parameter, navigationClrProperty);
MethodInfo selectMethodInfo;
selectType = OeExpressionHelper.GetCollectionItemType(e.Type);
if (selectType == null)
{
selectType = e.Type;
selectMethodInfo = OeMethodInfoHelper.GetSelectMethodInfo(sourceItemType, selectType);
}
else
{
selectMethodInfo = OeMethodInfoHelper.GetSelectManyMethodInfo(sourceItemType, selectType);
}
LambdaExpression lambda = Expression.Lambda(e, parameter);
source = Expression.Call(selectMethodInfo, source, lambda);
}
if (parseNavigationSegment.Filter != null)
{
var visitor = new OeQueryNodeVisitor(Visitor, Expression.Parameter(selectType));
e = visitor.TranslateNode(parseNavigationSegment.Filter.Expression);
LambdaExpression lambda = Expression.Lambda(e, visitor.Parameter);
MethodInfo whereMethodInfo = OeMethodInfoHelper.GetWhereMethodInfo(selectType);
source = Expression.Call(whereMethodInfo, source, lambda);
}
sourceItemType = selectType;
}
Visitor.ChangeParameterType(Expression.Parameter(sourceItemType));
return(source);
}
public Expression ApplySkipToken(Expression source, OeSkipTokenNameValue[] skipTokenNameValues, OrderByClause uniqueOrderBy, bool isDatabaseNullHighestValue)
{
if (skipTokenNameValues == null || skipTokenNameValues.Length == 0)
{
return(source);
}
var skipTokenTranslator = new Translators.OeSkipTokenTranslator(Visitor, _joinBuilder, isDatabaseNullHighestValue);
source = skipTokenTranslator.Build(source, skipTokenNameValues, uniqueOrderBy);
Visitor.ChangeParameterType(source);
return(source);
}
