我在表单中有一个按钮。每次单击按钮时都会加载一个组框（您可以参考我之前的问题）。每个组框中有几个文本框和标签。我为组框中的文本框引发了keydown事件。keydown事件执行一些数学计算。

• 链接到我之前的问题：Loading multiple Groupboxes in the form using the button_click event *

当只加载一个组框时，该按钮工作正常。但是，当加载第二个组框时，引发的事件对以前加载的组框中的文本框不起作用。它只对新的组框起作用。例如，如果在加载groupbox1后单击该按钮，则在第二次加载groupbox2时单击该按钮，等等...问题是keydown事件只对新加载的groupbox起作用。（即如果第三次点击按钮则keydown事件仅对组框3起作用。对于组框1和组框2，它不起作用）加载新的分组框时，应该如何保留前一个分组框中控件的事件。
我是这么试的：但问题依然存在。

int count;
private GroupBox GetGroupBox(int a)
        {
            groupBox = new GroupBox() { Text = "S" + (a.ToString()), Name = "S" + (a.ToString()), Width = 150, Height = 150, Location = new Point(15 + (count - 1) * (150 + 5), 270) };
                        
            for (int i=0; i<5; i++)
            {
                switch (i)
                {
                    case 1: // Add a TextBox and A Label
                        Tb1 = new TextBox() { Width = 40, Height = 10, Text = "Something", Location = new Point(75, 30) };
                        groupBox.Controls.Add(Tb1);
                        Tb1.KeyDown += Tb1_KeyDown;
                        lbl1 = new Label() { Name = "lbl1", Text = "r1.X", Width = 40, Height = 15, Location = new Point(10, 30) };
                        groupBox.Controls.Add(lbl1);
                        break;
                    case 2: // Add a TextBox and A Label
                        Tb2 = new TextBox() { Width = 40, Height = 10, Text = "Something", Location = new Point(75, 50) };
                        groupBox.Controls.Add(Tb2);
                        Tb2.KeyDown += Tb2_KeyDown;
                        lbl2 = new Label() { Name = "lbl2", Text = "r1.Y", Width = 40, Height = 15, Location = new Point(10, 50) };
                        groupBox.Controls.Add(lbl2);
                        break;
                    case 3: // Add a TextBox and A Label
                        Tb3 = new TextBox() { Width = 40, Height = 10, Text = "Something", Location = new Point(75, 70) };
                        groupBox.Controls.Add(Tb3);
                        Tb3.KeyDown += Tb3_KeyDown;
                        lbl3 = new Label() { Name = "lbl3", Text = "r1.Width", Width = 50, Height = 15, Location = new Point(10, 70) };
                        groupBox.Controls.Add(lbl3);
                        break;
                    case 4: // Add a TextBox and A Label
                        Tb4 = new TextBox() { Width = 40, Height = 10, Text = "Something", Location = new Point(75, 90) };
                        groupBox.Controls.Add(Tb4);
                        Tb4.KeyDown += Tb4_KeyDown;
                        lbl4 = new Label() { Name = "lbl4", Text = "r1.Height", Width = 50, Height = 15, Location = new Point(10, 90) };
                        groupBox.Controls.Add(lbl4);
                        break;
                }
            }            
            return groupBox;
        }
private void Tb4_KeyDown(object sender, KeyEventArgs e)
        {
            // / call a method to do something using the Tb.text as argument
        }
private void Tb3_KeyDown(object sender, KeyEventArgs e)
        {
            // / call a method to do something using the Tb.text as argument
        }
private void Tb2_KeyDown(object sender, KeyEventArgs e)
        {
            // / call a method to do something using the Tb.text as argument
        }
private void Tb1_KeyDown(object sender, KeyEventArgs e)
        {
            // call a method to do something using the Tb.text as argument
        }
private void button1_Click(object sender, EventArgs e)
        {
            this.Controls.Add(GetGroupBox(++count));            
        }

先谢谢你。