1.我这里有消息哦！！！——（窗体一）（可以是窗体也可以是用户控件）

 public partial class SelectForm : Form
    {
        public ComboBox FiltercomBox
        {
            get { return this.comboFilter; }
        }
        public UltraTree SelectTree
        {
            get { return this.ultraTree1; }//baolou
        }
        public UltraTextEditor InputConditionText
        {
            get { return this.txtInputCondition; }
        }
        public UltraButton BtnOK 
        {
            get { return this.btnOK; }//baolou
        }
        public UltraButton BtnSearch
        {
            get { return this.btnSearch; }
        }
        public SelectForm()
        {
            InitializeComponent();
        }
        public void IniitializeTree()
        {
            UltraTreeHelper.ForeachNodeWithProcess(SelectTree, node
                =>
            {
                node.Override.NodeStyle = NodeStyle.CheckBox;
            }
            );
            SelectTree.ExpandAll();
        }
    }

2.我需要你的信息，请给我，我需要使用！！！——（窗体二）

  private void btnSelect_Click(object sender, EventArgs e)
        {
            form.BtnOK.Click += BtnOK_Click;
            form.IniitializeTree();
            form.StartPosition = FormStartPosition.Manual;
            form.Location = new Point(480 + this.toolStrip1.Location.X + 40, 190 + this.toolStrip1.Location.Y + 20);
            form.Show();
        }

        private void BtnOK_Click(object sender, EventArgs e)
        {
            UltraTreeHelper.ForeachNodeWithProcess(form.SelectTree, node
                =>
            {
                if (node.CheckedState == CheckState.Checked)
                {
                    sNode.SelectNodeList.Add(node.Text);
                }
            }
            );
            foreach (string str in sNode.SelectNodeList)
            {
                DataTable dt = this.ultraGrid2.DataSource as DataTable;
                DataRow dr = dt.NewRow();
                dr["学科"] = str;
                dt.Rows.Add(dr);
            }
            form.Close();
        }

3.接下来，现场演示喽……

窗体二点击选择展示窗体一

窗体一进行选择树节点的操作，想把选择的节点传给窗体二并显示

点击确定，消息成功传达窗体二，棒棒哒！