DropDownList控制元件的基本用法
阿新 • • 發佈：2019-02-17
protectedvoid Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DateTime dt = DateTime.Now; DropDownList2.Items.Add(dt.Year.ToString()); DropDownList3.Items.Add(dt.Month.ToString()); DropDownList4.Items.Add(dt.Day.ToString());
} 
}//加減乘除protectedvoid Button1_Click(object sender, EventArgs e) { int a =int.Parse(TextBox1.Text); int b =int.Parse(TextBox2.Text); int c =0; switch(DropDownList1.SelectedValue) { case"+" c = a + b; Label2.Text = c.ToString(); break; case"-": c = a - b; Label2.Text = c.ToString(); break; case"*": c = a * b; Label2.Text = c.ToString(); case"/": c = a / b; Label2.Text = c.ToString(); break; } }//DropDownList 改變index時發生的事件protectedvoid DropDownList4_SelectedIndexChanged(object sender, EventArgs e) { Response.Write(DropDownList2.SelectedValue+"-"+ DropDownList3.SelectedValue+"-"+DropDownList4.SelectedValue); } //CheckBoxList 改變index時發生的事件protectedvoid CheckBoxList1_SelectedIndexChanged(object sender, EventArgs e) { for (int i =0; i < CheckBoxList1.Items.Count; i++) { if (CheckBoxList1.Items[i].Selected) //注意啟用postback，這樣可以實時觀測{ Response.Write(CheckBoxList1.Items[i].Text); } } }