BidirectionalGraph

The BidirectionalGraph<TVertex, TEdge> provides an efficient data structure to access the out edges and the in edges of a vertex of sparse directed graphs. This class is mutable, serializable, cloneable and can be constructed in many different ways. Internally, the data structure keeps a dictionary from TVertex to a unordered list of TEdge elements.

vargraph=newBidirectionalGraph<int,Edge<int>>();
...foreach(varvertexingraph.Vertices)foreach(varedgeingraph.InEdges(vertex))Console.WriteLine(edge);

If you only need to access out-edges, consider using the AdjacencyGraph, as it uses half the memory.