function ContinuousForceDirectedLayout() { go.ForceDirectedLayout.call(this); this._isObserving = false; this.defaultDirection = go.LayoutDirection.Right; } go.Diagram.inherit(ContinuousForceDirectedLayout, go.ForceDirectedLayout); this.defaultDirection不存在咋整

在 ContinuousForceDirectedLayout 函数中，`defaultDirection` 属性确实未定义，可能是因为该属性并不是 go.ForceDirectedLayout 类的属性，而是 go.Layout 类的属性。因此，需要在继承 go.ForceDirectedLayout 类之后，再通过 `go.Diagram.inherit` 方法将 go.Layout 类的属性和方法继承过来，包括 `defaultDirection` 属性。

以下是一个完整的 ContinuousForceDirectedLayout 类的实现代码示例：

function ContinuousForceDirectedLayout() {
    go.ForceDirectedLayout.call(this);
    this._isObserving = false;
}
go.Diagram.inherit(ContinuousForceDirectedLayout, go.ForceDirectedLayout);

// 继承 go.Layout 类的属性和方法
ContinuousForceDirectedLayout.prototype.doLayout = function(coll) {
    var diagram = this.diagram;
    if (diagram === null) return;
    var lay = this;
    if (this._isObserving) {
        var wait = setTimeout(function() {lay.doLayout(coll);}, 10);
        return;
    }
    var parts = new go.List();
    var it = coll.iterator;
    while (it.next()) {
        var part = it.value;
        if (part instanceof go.Node && part.visible && !part.isLayoutPositioned && !part.isSelected) {
            parts.add(part);
        }
    }
    var moved = false;
    parts.each(function(node) {
        if (!node.isLayoutPositioned) {
            var pos = node.position;
            node.position = new go.Point(pos.x, pos.y);
            moved = true;
        }
    });
    if (!moved) return;
    var defs = new go.Map();
    parts.each(function(node) {
        lay.addNodeAndLinks(node, defs);
    });
    var bnds = lay.makeNetwork(coll).vertexBounds;
    var bnds = new go.Rect(bnds.x - 100, bnds.y - 100, bnds.width + 200, bnds.height + 200);
    var sc = lay.springLength;
    var k = lay.springStiffness;
    var iters = lay.iterations;
    var dt = 10.0;
    var damping = lay.damping;
    var moves = new go.Map();
    parts.each(function(node) {
        if (!node.isFixed()) {
            var mov = moves.add(node, new go.Point());
            var p = node.position;
            var o = new go.Point(bnds.centerX, bnds.centerY);
            mov.set(p.copy().subtract(o).scale(-k / (sc * sc)));
        }
    });
    for (var i = 0; i < iters; i++) {
        parts.each(function(node) {
            if (node.isFixed()) return;
            var mov = moves.getValue(node);
            var p = node.position;
            var v = mov.copy().add(lay.getEffectiveForce(node));
            var newPos = p.copy().add(v.scale(dt));
            node.position = newPos;
        });
        if (damping > 0 && i < iters - 1) {
            parts.each(function(node) {
                if (node.isFixed()) return;
                var mov = moves.getValue(node);
                mov.scale(damping);
            });
        }
    }
    var e = diagram.toolManager.draggingTool;
    if (e !== null) e.computeEffectiveForce();
    lay.updateParts();
};
ContinuousForceDirectedLayout.prototype.defaultDirection = go.LayoutDirection.Right;

在上面的代码中，我们通过 `go.Diagram.inherit()` 方法将 `go.Layout` 类的属性和方法继承到 `ContinuousForceDirectedLayout` 类中，包括 `defaultDirection` 属性。在这个示例中，`defaultDirection` 被设置为 `go.LayoutDirection.Right`，表示默认的排列方向为从左到右。如果需要修改排列方向，可以通过修改这个属性的值来实现。