实现效果:

知识运用:
TabControl控件的TabPages属性的Add方法
public TabControl.TabPageCollection TabPages {get;} //获取选项卡控件中选项卡页的集合
public void Add(TabPage value)
实现代码:
private void button1_Click(object sender, EventArgs e)
{
string Title = "New(" + (tabControl1.TabCount+1).ToString() + ")";
TabPage tp = new TabPage(Title);
tabControl1.TabPages.Add(tp);
MessageBox.Show("现在有"+tabControl1.TabCount+"个选项卡 ");
}