Generic Classes

[kegtappa]

I'm having some trouble with a generic class I'm trying to create. I'd like to use this class to perform DFS searches on different variations of a base graph class, but the compiler doesn't agree with me. The errors I'm getting are: unknown type "NodeType", and unknown type "EdgeType". (Which I think is funny because intellisense pickups up the definition just fine and shows me a tool tip with the class definition of the SparseGraph class including the where clause. So I know it KNOWS the definition I'm trying to use... but I digress)

class SearchGraphDFS<GraphType> where GraphType : SparseGraph<NodeType,EdgeType>

class SparseGraph<NodeType, EdgeType> where NodeType : GraphNode, new() where EdgeType : GraphEdge, new()

class GraphEdge

class GraphNode

So to be clear the "SearchGraphDFS" class is the problem. The compiler (VS2008) errors on NodeType and EdgeType. The other 3 class definitions are included for clarity.

The question is if my way isn't the correct way to implement what I'm trying to achieve, then what is? Or is there a way I can define NodeType and EdgeType without having to do something like this?

class SearchGraphDFS<GraphType,NodeType,EdgeType> where GraphType : SparseGraph<NodeType,EdgeType>

[kegtappa]

Uh oh yeah, I forgot to give my versions.

Visual Studio 2008 Version 9.0.30729.1 SP
.NET Framework Version 3.5 SP1

[rohshall]

Are the classes NodeType and EdgeType defined in a custom namespace you forgot to import using 'using'?

[kegtappa]

No, NodeType and EdgeType are generic type identifiers defined in my "SparseGraph" class.

class SparseGraph<NodeType, EdgeType> where NodeType : GraphNode, new() where EdgeType : GraphEdge, new()

[vcdebugger]

try to reverse the order in which you have declared your classes and see .. like this :

 
class GraphEdge

class GraphNode

class SparseGraph<NodeType, EdgeType> where NodeType : GraphNode, new() where 
EdgeType : GraphEdge, new()

class SearchGraphDFS<GraphType> where GraphType : SparseGraph<NodeType,EdgeType>

may be the compiler is trying to find the declarations/definitions of those subclasses first..

[rohshall]

class SearchGraphDFS<GraphType,NodeType,EdgeType> where GraphType : SparseGraph<NodeType,EdgeType>

Under where constraint, you can specify either a class or an interface. However, in this case, your constraint is a generic class and not a concrete class.
So, you need to give the concrete types for SparseGraph class instantiation like
SparseGraph<GraphNode, GraphEdge>

[kegtappa]

Under where constraint, you can specify either a class or an interface. However, in this case, your constraint is a generic class and not a concrete class.
So, you need to give the concrete types for SparseGraph class instantiation like
SparseGraph<GraphNode, GraphEdge>

Seems to be working so far, thanks!