/// <summary>
/// This predicate is true if it is permissible to connect a link to a given node/port.
/// </summary>
/// <param name="tonode"></param>
/// <param name="toport"></param>
/// <returns>
/// False if the <paramref name="tonode"/> is in a <see cref="Layer"/> that does not <see cref="Layer.AllowLink"/>.
/// False if <see cref="Node.GetLinkableTo"/> for the <paramref name="toport"/> is either false or null.
/// False if the number of links connected to the <paramref name="toport"/> would exceed the <see cref="Node.GetLinkableMaximum"/> value.
/// Otherwise true.
/// </returns>
public virtual bool IsValidTo(Node tonode, FrameworkElement toport) {
if (tonode == null || toport == null) {
var lmodel = this.Diagram.Model as ILinksModel;
return (lmodel != null && lmodel.ValidUnconnectedLinks == ValidUnconnectedLinks.Allowed);
}
if (tonode.Layer != null && !tonode.Layer.AllowLink) return false;
if (Node.GetLinkableTo(toport) != true) return false; // false or null value means not linkable
int maxlinks = Node.GetLinkableMaximum(toport);
if (maxlinks < int.MaxValue) {
//??? wrong number, because RelinkingTool doesn't temporarily disconnect?
if (this.OriginalLink != null && tonode == this.OriginalToNode && toport == this.OriginalToPort) return true;
if (tonode.FindLinksConnectedWithPort(tonode.GetPortName(toport)).Count() >= maxlinks) return false;
}
return true;
}
/// <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);
}
}
/// <summary>
/// This predicate is true if it is permissible to connect a link from a given node/port.
/// </summary>
/// <param name="fromnode"></param>
/// <param name="fromport"></param>
/// <returns>
/// False if the <paramref name="fromnode"/> is in a <see cref="Layer"/> that does not <see cref="Layer.AllowLink"/>.
/// False if <see cref="Node.GetLinkableFrom"/> for the <paramref name="fromport"/> is either false or null.
/// False if the number of links connected to the <paramref name="fromport"/> would exceed the <see cref="Node.GetLinkableMaximum"/> value.
/// Otherwise true.
/// </returns>
public virtual bool IsValidFrom(Node fromnode, FrameworkElement fromport) {
if (fromnode == null || fromport == null) return false;
if (fromnode.Layer != null && !fromnode.Layer.AllowLink) return false;
if (Node.GetLinkableFrom(fromport) != true) return false; // false or null value means not linkable
int maxlinks = Node.GetLinkableMaximum(fromport);
if (maxlinks < Int32.MaxValue) {
//??? wrong number, because RelinkingTool doesn't temporarily disconnect?
if (this.OriginalLink != null && fromnode == this.OriginalFromNode && fromport == this.OriginalFromPort) return true;
if (fromnode.FindLinksConnectedWithPort(fromnode.GetPortName(fromport)).Count() >= maxlinks) return false;
}
return true;
}
