private bool LinkableToStationaryNode(Node n, Node stationary) {
if (n == null) return false;
if (n == stationary) return false; // shouldn't happen, but might as well check anyway
var links = n.LinksOutOf.ToList();
if (links.Count > 1) return false; //?? multiple links: disallow
Link relink = null;
if (links.Count == 1) { // one link: relink if not connected with a dragged node
relink = links.First();
Node other = relink.ToNode; // assume IsValidLink will check for relink valid
if (other != null && other.IsSelected) return false;
} // zero links: new link, assume IsValidLink will check for new link valid
// ignore all nodes that are members of a selected Group
if (this.Diagram.SelectedParts.OfType<Group>().Any(g => n.IsContainedBy(g))) return false;
return IsValidLink(n, stationary, relink);
}
/// <summary>
/// This predicate should be true when it is logically valid to connect a link from
/// one node/port to another node/port.
/// </summary>
/// <param name="fromnode">the "from" <see cref="Node"/></param>
/// <param name="fromport">the "from" <c>FrameworkElement</c></param>
/// <param name="tonode">the "to" <see cref="Node"/> (perhaps the same as <paramref name="fromnode"/>)</param>
/// <param name="toport">the "to" <c>FrameworkElement</c> (perhaps the same as <paramref name="fromport"/>)</param>
/// <returns>
/// False if <see cref="IsValidFrom"/> is false for the <paramref name="fromnode"/> and <paramref name="fromport"/>.
/// False if <see cref="IsValidTo"/> is false for the <paramref name="tonode"/> and <paramref name="toport"/>.
/// False if <see cref="IsInSameNode"/> is true unless <see cref="Node.GetLinkableSelfNode"/> is true for both ports.
/// False if <see cref="IsLinked"/> is true unless <see cref="Node.GetLinkableDuplicates"/> is true for both ports.
/// False if trying to link to the link's own label node(s).
/// False if <see cref="IDiagramModel.IsLinkValid"/> or one of the model-specific <c>IsRelinkValid</c> methods is false,
/// depending on whether <see cref="OriginalLink"/> is null (a new link) or non-null (a relink).
/// Otherwise true.
/// </returns>
public virtual bool IsValidLink(Node fromnode, FrameworkElement fromport, Node tonode, FrameworkElement toport) {
if (this.Diagram == null || this.Diagram.PartManager == null) return false;
//?? allow partly connected or unconnected links
if (!IsValidFrom(fromnode, fromport)) return false;
if (!IsValidTo(tonode, toport)) return false;
if (fromport != null && toport != null) {
if (!(Node.GetLinkableSelfNode(fromport) && Node.GetLinkableSelfNode(toport)) && IsInSameNode(fromport, toport)) return false;
if (!(Node.GetLinkableDuplicates(fromport) && Node.GetLinkableDuplicates(toport)) && IsLinked(fromport, toport)) return false;
}
// disallow linking to the link's own label(s)
if (this.OriginalLink != null) {
if (fromnode != null && fromnode.IsContainedBy(this.OriginalLink)) return false;
if (tonode != null && tonode.IsContainedBy(this.OriginalLink)) return false;
}
Object fromdata = (fromnode != null ? fromnode.Data : null);
Object fromid = (fromnode != null ? fromnode.GetPortName(fromport) : null);
Object todata = (tonode != null ? tonode.Data : null);
Object toid = (tonode != null ? tonode.GetPortName(toport) : null);
IDiagramModel model = this.Diagram.PartManager.FindCommonDataModel(fromdata, todata);
if (model == null) {
if (fromnode != null) model = fromnode.Model;
else if (tonode != null) model = tonode.Model;
var lmodel = model as ILinksModel;
if (lmodel == null || lmodel.ValidUnconnectedLinks == ValidUnconnectedLinks.None) return false;
// if the model allows unconnected links, it's OK
}
if (this.OriginalLink != null) {
ILinksModel lmodel = model as ILinksModel;
if (lmodel != null) return lmodel.IsRelinkValid(fromdata, fromid, todata, toid, this.OriginalLink.Data);
IConnectedModel cmodel = model as IConnectedModel;
if (cmodel != null) return cmodel.IsRelinkValid(fromdata, todata, this.OriginalLink.FromData, this.OriginalLink.ToData);
ITreeModel tmodel = model as ITreeModel;
if (tmodel != null) return tmodel.IsRelinkValid(fromdata, todata, this.OriginalLink.FromData, this.OriginalLink.ToData);
return false;
} else {
return model.IsLinkValid(fromdata, fromid, todata, toid);
}
}
private bool LinkableFromStationaryNode(Node n, Dictionary<Part, Info> dragged, Node stationary) {
if (n == null) return false;
if (n == stationary) return false; // shouldn't happen, but might as well check anyway
var links = n.LinksInto.ToList();
if (links.Count > 1) return false; //?? multiple links: disallow
Link relink = null;
if (links.Count == 1) { // one link: relink if not connected with a dragged node
relink = links.First();
Node other = relink.FromNode; // assume IsValidLink will check for relink valid
if (other != null && dragged.ContainsKey(other)) return false;
} // zero links: new link, only need to check IsValidLink
// ignore all nodes that are members of a dragged Group
if (dragged.OfType<Group>().Any(g => n.IsContainedBy(g))) return false;
return IsValidLink(stationary, n, relink);
}
