三色交替的下拉式清單方塊

如所示，顯示三種顏色交替的下拉框。

    實現方法：

1．使用System.Web.UI.HtmlControls控制項，把它作為伺服器控制項運行。

2．在後台為這個select控制項綁定資料。

3．再調用一個自己寫的函數為它的沒個項目指定顏色。

        實現代碼（主要實現部分）：

前台（WebForm1.aspx）：

     <SELECT id="Select1" style="WIDTH: 300px" name="Select1" runat="server">

         <OPTION selected></OPTION>

     </SELECT>

後台（WebForm1.aspx.cs）：

     private void Page_Load(object sender, System.EventArgs e)

     {

         if(!IsPostBack)

         {

              SqlConnection cnn = new SqlConnection();

          cnn.ConnectionString = "data source=localhost;initial catalog=Northwind;password=;"

              +"persist security info=True;user id=sa;workstation id=APJ062;packet size=4096";

              string sqlstr = "select Top 10 CustomerID, CompanyName from Customers";

              cnn.Open();

              SqlDataAdapter ad = new SqlDataAdapter(sqlstr,cnn);

              DataTable dt = new DataTable();

              ad.Fill(dt);

 

 

 

              Select1.DataSource = dt;

              Select1.DataTextField = "CompanyName";

              Select1.DataValueField = "CustomerID";

              Select1.DataBind();

 

 

 

              BindSelectColor(Select1);

         }

     }

     //為select控制項的項目添加樣式

     void BindSelectColor(HtmlSelect select) 

     {

         int num = 0;

         string styleString = "";

         for(int i = 0 ; i < select.Items.Count; i ++ )

         {

              num = i % 3;

              switch(num)

              {

                   case 0:

                   {

                       styleString = "COLOR: #000099; BACKGROUND-COLOR: #F4FAFF";

                       break;

                   }

                   case 1:

                   {

                       styleString = "COLOR: #990000; BACKGROUND-COLOR: #FFFAFB";

                       break;

                   }

                   case 2:

                   {

                       styleString = "COLOR: #009900; BACKGROUND-COLOR: #F4FFFA";

                       break;

                   }

              }

              select.Items[i].Attributes.Add("style",styleString);

         }

     }