private void StartNodeButtonDown(object sender, MouseButtonEventArgs e) { //开始节点 if (this.WorkflowProcessCurrent.StartNode == null) { StartNodeControl snc = new StartNodeControl(this, null, false); snc.InitNode(); if (!canvas.Children.Contains(snc)) { snc.LoadNode(); //设置位置 Point p = e.GetPosition(canvas); snc.SetPoint((double)(p.X - snc.Bounds.Width / 2), (double)(p.Y - snc.Bounds.Height / 2)); this.AddHandle(snc); canvas.Children.Add(snc); this.WorkflowProcessCurrent.StartNode = snc.StartNode; UserControls.Add(snc.Id, snc); } } else { MainPage.Message("提示", "只能有一个开始节点。"); } listBox.SelectedIndex = 0; }