static void test()
{
Expression <Func <Order, List <OrderLine> > > selectOrderLines = o => o.Lines;
Expression <Func <List <OrderLine>, Boolean> > validateOrderLines = lines => lines.Count > 0;
var validateOrder = ParameterToMemberExpressionRebinder.CombinePropertySelectorWithPredicate(selectOrderLines, validateOrderLines);
// validateOrder: {o => (o.Lines.Count > 0)}
}
public void ShouldReflectivelyChangeCollectionParameterForLambdaIntoMemberAccessor()
{
var data = new List <ExampleLeaf>
{
new ExampleLeaf
{
SecuredRoots = new[]
{
new ExampleRoot
{
Id = 1
}
}
},
new ExampleLeaf
{
SecuredRoots = new[]
{
new ExampleRoot
{
Id = 4
}
}
},
new ExampleLeaf
{
SecuredRoots = new[]
{
new ExampleRoot
{
Id = 5
}
}
}
};
Expression <Func <ExampleLeaf, IEnumerable <ExampleRoot> > > selector = x => x.SecuredRoots;
LambdaExpression selectorExpression = selector;
List <long> ids = new List <long> {
1, 2, 3
};
Expression <Func <IEnumerable <ExampleRoot>, bool> > predicate = x => x.Any(c => ids.Contains(c.Id));
LambdaExpression predicateExpression = predicate;
// x => x.SecuredRoots.Any(c => ids.Contains(c.Id))
var resultingCombined = ParameterToMemberExpressionRebinder.CombineSinglePropertySelectorWithPredicate(selectorExpression, predicateExpression);
var resultingPredicate = (Func <ExampleLeaf, bool>)resultingCombined.Compile();
var results = data.Where(resultingPredicate);
results.Should().HaveCount(1);
}
public void CombineTwoObjectExpressions()
{
Expression <Func <Employee, object> > filter1 = p => p.Info;
Expression <Func <Employee, object> > filter2 = p => p.Profile;
// Trying to combine two object expressions fails
Expression <Func <Employee, object> > filterCombined = ParameterToMemberExpressionRebinder.CombinePropertySelectorWithPredicate(filter1, filter2);
filterCombined.Body.ToString().ShouldBe("((p => p.Info And p => p.Profile))"); //Something like this anyway...
}
public static Expression <Func <T, bool> > CombinePropertySelectorWithPredicate <T, T2>(
Expression <Func <T, T2> > propertySelector,
Expression <Func <T2, bool> > propertyPredicate)
{
var memberExpression = propertySelector.Body as MemberExpression;
if (memberExpression == null)
{
throw new ArgumentException("propertySelector");
}
var expr = Expression.Lambda <Func <T, bool> >(propertyPredicate.Body, propertySelector.Parameters);
var rebinder = new ParameterToMemberExpressionRebinder(propertyPredicate.Parameters[0], memberExpression);
expr = (Expression <Func <T, bool> >)rebinder.Visit(expr);
return(expr);
}
public void ShouldChangeParameterForLambdaIntoMemberAccessor()
{
var data = new List <ExampleLeaf>
{
new ExampleLeaf
{
SecuredRoot = new ExampleRoot
{
Id = 1
}
},
new ExampleLeaf
{
SecuredRoot = new ExampleRoot
{
Id = 4
}
},
new ExampleLeaf
{
SecuredRoot = new ExampleRoot
{
Id = 5
}
}
};
Expression <Func <ExampleLeaf, ExampleRoot> > selector = x => x.SecuredRoot;
List <long> ids = new List <long> {
1, 2, 3
};
Expression <Func <ExampleRoot, bool> > predicate = x => ids.Contains(x.Id);
// x => ids.Contains(x.SecuredRoot.Id)
var resultingCombined = ParameterToMemberExpressionRebinder.CombineSinglePropertySelectorWithPredicate(selector, predicate);
var resultingPredicate = resultingCombined.Compile();
var results = data.Where(resultingPredicate);
results.Should().HaveCount(1);
}
