下拉框

// AutoPostBack和OnSelectedIndexChanged是为了控制函数回调

<asp:DropDownList ID="ddlGrade" runat="server" AutoPostBack="True" 
OnSelectedIndexChanged="ddlChange_SelectedIndexChanged"></asp:DropDownList>

<asp:DropDownList ID="ddlPassTypeList" runat="server" AutoPostBack="True" 
OnSelectedIndexChanged="ddlPassTypeList_SelectedIndexChanged">
    <asp:ListItem Value="All">[所有]</asp:ListItem>
    <asp:ListItem Value="1">已审核</asp:ListItem>
    <asp:ListItem Value="0">未审核</asp:ListItem>
</asp:DropDownList>

选中下拉框

js获取asp标签的ID：$("#<%=ddlTypeYear.ClientID%>")

.aspx中选中第0个选项

addDdlDept.SelectedValue = Convert.ToString(0);

在javascript中选中指定的选择框

• 根据value来指定

$("#<%=ddlTypeYear.ClientID%>").val("[请选择]");
$("#<%=ddlTypeStoragePeriod.ClientID%>").val("[请选择]");
$("#<%=addTypeDdlDept.ClientID%>").val("[请选择]");

• 根据index来指定

$("#<%=ddlTypeYear.ClientID%>")[0].selectedIndex = 0;
$("#<%=ddlTypeStoragePeriod.ClientID%>")[0].selectedIndex = 0;
$("#<%=addTypeDdlDept.ClientID%>")[0].selectedIndex = 0;

给下拉框赋值

• 从数据库表中取数据赋值给下拉框

ddlDept.Items.Clear();
string strDepart = "select ClassName,Id from FM_ListClass where DeleteSign = 0";
zhyFunctions.GetDropDownList(ddlDept, strDepart, "ClassName", "Id", 1);
// ddlDept：下拉框的Id 
//数据库表中字段：ClassName：显示出来的Text， Id：Value的值

• 用枚举方法给下拉框赋值

//  定义枚举
public class FileManageConfig
{
    public enum FilePass
    {
        [EnumValue(1, "已归档")]
        Pass = 1,
        [EnumValue(0, "未归档")]
        UnPass = 0,
        [EnumValue(-1, "不知道")]
        nokonw = 0,
    }
}

// FileManageConfig.FilePass是枚举方法的路径
ddlPass.Items.Clear();
ddlPass.Items.Add(new ListItem("[全部]", "All"));
BidirHashtable<object, EnumValueAttribute> passMap = EnumConvertUtils.EnumToAttributeMap(typeof(FileManageConfig.FilePass));
foreach (string passStatus in Enum.GetNames(typeof(FileManageConfig.FilePass)))
{
    ddlPass.Items.Add(new ListItem((string)passMap[Enum.Parse(typeof(FileManageConfig.FilePass), passStatus)].DisplayValue, Convert.ToString((int)passMap[Enum.Parse(typeof(FileManageConfig.FilePass), passStatus)].DbValue)));
}