comboBox控件

  /// 应用程序的主入口点。
  ///
  [STAThread]
  static void Main()
  {
   Application.Run(new Form1());
  }

  private void Form1_Load(object sender, System.EventArgs e)
  {
   this.Text = "ComboBox控件使用示例";

   label1.Text = "Simple";
   label1.AutoSize = true;//自动尺寸
   label2.Text = "Dropdown";//下拉
   label2.AutoSize = true;
   label3.Text = "DropdownList";
   label3.AutoSize = true;
   label4.Text = "被选中的项";
   label4.AutoSize = true;

   textBox1.Text = "";

   string[] strCountry = {"中国","朝鲜","越南","老挝","缅甸 ","印度","尼泊尔","俄罗斯"};
   for(int i = 0; i < strCountry.Length;i++)//条件
   {
       comboBox1.Items.Add(strCountry[i]);
    comboBox2.Items.Add(strCountry[i]);
    comboBox3.Items.Add(strCountry[i]);
            }

   comboBox1.DropDownStyle = ComboBoxStyle.Simple;
   comboBox2.DropDownStyle = ComboBoxStyle.DropDown;
   comboBox3.DropDownStyle = ComboBoxStyle.DropDownList;
   comboBox1.Text = "";
   comboBox2.Text = "";
   comboBox3.Text = "";

    }

  private void comboBox1_SelectedIndexChanged(object sender, System.EventArgs e)
  {
   if(comboBox1.SelectedIndex > -1)//如果被选择的大于-1就被选上
   {
       textBox1.Text += comboBox1.Text + ";";//直接在后面连
    label4.Text = "comboBox1键盘选择的选项";
   }
  }

  private void comboBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
  {
   if(e.KeyChar == (char)Keys.Enter)//e消息，按下去的键，==判断,打了回车键之后作什么
   {
       textBox1.Text += comboBox1.Text + ";";
    label4.Text = "comboBox1键盘输入的选项";
   }
  }
 }
}