<td style="width: 30px;" align="right">
年月:
</td>
<td>
<asp:DropDownList ID="ddl_ksyear" runat="server" class="easyui-combobox" Width="60">
</asp:DropDownList>
<asp:DropDownList ID="ddl_ksmonth" runat="server" class="easyui-combobox" Width="40">
</asp:DropDownList>
</td>
<td style="width: 15px;" align="right">
至
</td>
<td>
<asp:DropDownList ID="ddl_jsyear" runat="server" class="easyui-combobox" Width="60">
</asp:DropDownList>
<asp:DropDownList ID="ddl_jsmonth" runat="server" class="easyui-combobox" Width="40">
</asp:DropDownList>
</td>

 ddl_ksyear.DataSource = FormBase.getYEAR();
            ddl_ksyear.DataTextField = "YEAR";
            ddl_ksyear.DataValueField = "YEAR";
            ddl_ksyear.DataBind();
            ddl_ksyear.SelectedValue = DateTime.Now.AddMonths(-1).Year.ToString();
//因为这里数据源是返回是datatable，且只有一列 year
//所以键值对都是该字段，同时给予默认的。
关键点：
DataTextField 文本
DataValueField  值
DataBind  绑定数据源
SelectedValue   当前选择