添加到datagridview的C＃自定义Treeview控件未在前面显示

Question

添加到datagridview的自定义树视图控件未显示在前面。 尝试使用treeView1.BringToFront（）;但结果相同。

        private void dataGridViewProblem_CellEnter(object sender, DataGridViewCellEventArgs e)
        {
            if (treeView1 != null)
            {
                treeView1.Visible = false;
            }

            if (e.RowIndex != -1 && e.ColumnIndex == dataGridViewProblem.Columns["Category"].Index)
            {
                dataGridViewProblem.Controls.Add(treeView1);

                // It returns the retangular area that represents the Display area for a cell  
                Rectangle oRectangle = dataGridViewProblem.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, true);

                //Setting area for DateTimePicker Control  
                treeView1.Size = new Size(oRectangle.Width, treeView1.Height);

                // Setting Location
                treeView1.Location = new Point(oRectangle.X, oRectangle.Y + oRectangle.Height);

                treeView1.BringToFront();
                treeView1.Visible = true;
            }
        }