C# Visual.FireOnVisualParentChanged方法代码示例

        /// <summary>
        /// DisconnectChild
        ///
        ///    Derived classes must call this method to notify the Visual layer that a
        ///    child was removed from the children collection. The Visual layer will then call
        ///    GetChildren to find out which child has been removed.
        ///
        /// </summary>
        protected void RemoveVisualChild(Visual child)
        {
            if (child == null || child._parent == null)
            {
                return;
            }

            if (child._parent != this)
            {
                throw new ArgumentException(SR.Get(SRID.Visual_NotChild));
            }

            if(InternalVisual2DOr3DChildrenCount == 0)
            {
                SetFlags(false, VisualFlags.HasChildren);
            }

            //
            // Remove the child on all channels its current parent is marshalled to.
            //

            for (int i = 0; i < _proxy.Count; i++)
            {
                DUCE.Channel channel = _proxy.GetChannel(i);

                if (child.CheckFlagsAnd(channel, VisualProxyFlags.IsConnectedToParent))
                {
                    child.SetFlags(channel, false, VisualProxyFlags.IsConnectedToParent);
                    DUCE.IResource childResource = (DUCE.IResource)child;
                    childResource.RemoveChildFromParent(this, channel);
                    childResource.ReleaseOnChannel(channel);
                }
            }

            // Set the parent pointer to null.

            child._parent = null;

            Visual.PropagateFlags(
                this,
                VisualFlags.IsSubtreeDirtyForPrecompute,
                VisualProxyFlags.IsSubtreeDirtyForRender);

            UIElement.PropagateSuspendLayout(child);

            // Fire notifications
            child.FireOnVisualParentChanged(this);
            OnVisualChildrenChanged(null /* no child added */, child);
        }

        /// <summary>
        /// DisconnectChild
        ///
        ///    This method is called to remove the 2D visual child of the Viewport2DVisual3D
        ///
        /// </summary>
        private void RemoveVisualChild(Visual child)
        {
            if (child == null || child._parent == null)
            {
                return;
            }

            if (child._parent != this)
            {
                throw new ArgumentException(SR.Get(SRID.Visual_NotChild));
            }

            // NOTE: We'll let the VisualBrush handle final cleanup from the channel
            //
           
            child._parent = null;

            // NOTE: We also let the VisualBrush handle any flag propagation issues (so Visual(3D).RemoveVisualChild for
            //       the things they propagate) as well as layout.
            
            // Fire notifications
            child.FireOnVisualParentChanged(this);
            OnVisualChildrenChanged(null /* no child added */, child);
        }

        /// <summary>
        /// AttachChild
        ///
        ///    Derived classes must call this method to notify the Visual layer that a new
        ///    child appeard in the children collection. The Visual layer will then call the GetVisualChild
        ///    method to find out where the child was added.
        ///
        ///  Remark: To move a Visual child in a collection it must be first disconnected and then connected
        ///    again. (Moving forward we might want to add a special optimization there so that we do not
        ///    unmarshal our composition resources).
        ///
        ///    It is okay to type this protected API to the 2D Visual.  The only 2D Visual with
        ///    3D childern is the Viewport3DVisual which is sealed.  -- [....] 01/17/06
        /// </summary>
        protected void AddVisualChild(Visual child)
        {
            if (child == null)
            {
                return;
            }

            if (child._parent != null)
            {
                throw new ArgumentException(SR.Get(SRID.Visual_HasParent));
            }

            SetFlags(true, VisualFlags.HasChildren);

            // Set the parent pointer.

            child._parent = this;

            //
            // The child might be dirty. Hence we need to propagate dirty information
            // from the parent and from the child.
            //

            Visual.PropagateFlags(
                this,
                VisualFlags.IsSubtreeDirtyForPrecompute,
                VisualProxyFlags.IsSubtreeDirtyForRender);

            Visual.PropagateFlags(
                child,
                VisualFlags.IsSubtreeDirtyForPrecompute,
                VisualProxyFlags.IsSubtreeDirtyForRender);

            //
            // Resume layout.
            //
            UIElement.PropagateResumeLayout(this, child);

            // Fire notifications
            this.OnVisualChildrenChanged(child, null /* no removed child */);
            child.FireOnVisualParentChanged(null);
        }

        /// <summary>
        /// AttachChild
        ///
        ///    This method is called to add a 2D Visual child to the Viewport2DVisual3D
        ///
        /// </summary>
        private void AddVisualChild(Visual child)
        {
            if (child == null)
            {
                return;
            }

            if (child._parent != null)
            {
                throw new ArgumentException(SR.Get(SRID.Visual_HasParent));
            }

            // Set the parent pointer.

            child._parent = this;

            // NOTE: Since the 2D object is on a VisualBrush, it will allow it to handle
            // the dirtyness of the 2D object, realization information, as well as layout.  See
            // Visual(3D).AddVisualChild for the things they propagate on adding a new child
            
            // Fire notifications
            this.OnVisualChildrenChanged(child, null /* no removed child */);
            child.FireOnVisualParentChanged(null);
        }