我有一个带有 3 个下拉列表和文本框的小页面。我的目标是在每个下拉框（或任何组合）中选择一个值，然后在回发后将所选值设置为上次搜索的值。问题之一是 1. 在 IE 中的每次选择之后，页面都会回发（显然），即使添加了启用视图状态的属性，下拉列表也不会保留所选值。
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="QSerch.aspx.cs" Inherits="QSerch"
EnableViewState="true" EnableEventValidation="true" EnableViewStateMac="true"%>
<%@ Register Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
Namespace="System.Web.UI" TagPrefix="asp" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<style type="text/css">
.ddlstl
{
font-size: 13px;
font-family: Arial;
}
#Iframe1
{
height: 700px;
width: 540px;
}
.style2
{
width: 243px;
}
</style>
</head>
<body dir="rtl">
<form id="form1" runat="server" enableviewstate="true">
<asp:ScriptManager ID="ScriptManager1" runat="server" EnableScriptGlobalization="True"
EnablePartialRendering="true" LoadScriptsBeforeUI="false" ScriptMode="Release">
</asp:ScriptManager>
<div style="float: right; width: 28px;">
</div>
<div style="text-align: right; float: right;">
<table border="0" cellpadding="0" cellspacing="0">
<tr>
<td>
<table border="0">
<tr>
<td style="width: 170px;">
<asp:DropDownList ID="ddlMec" runat="server" AutoPostBack="True" CssClass="ddlstl"
Height="22px" Width="160px" EnableViewState="true" OnSelectedIndexChanged="ddlMec_SelectedIndexChanged">
</asp:DropDownList>
</td>
</tr>
<tr>
<td style="width: 20px;">
<asp:DropDownList ID="ddlTMec" runat="server" AutoPostBack="True" CssClass="ddlstl"
Height="22px" Width="160px" OnSelectedIndexChanged="ddlTMec_SelectedIndexChanged"
EnableViewState="true">
<asp:ListItem Value="-1">בחר תפקיד</asp:ListItem>
</asp:DropDownList>
</td>
</tr>
<tr>
<td style="width: 170px;">
<asp:DropDownList ID="ddlArea" runat="server" AutoPostBack="True" CssClass="ddlstl"
DataSourceID="adsArea" DataTextField="name_area" DataValueField="id_area" Height="22px"
Width="160px" OnSelectedIndexChanged="ddlArea_SelectedIndexChanged" AppendDataBoundItems="true"
EnableViewState="true">
<asp:ListItem Value="-1" Text="בחר איזור"></asp:ListItem>
</asp:DropDownList>
<asp:AccessDataSource ID="adsArea" runat="server" DataFile="~/App_Data/Adam.mdb"
SelectCommand="SELECT [id_area], [name_area] FROM [table_area] ORDER BY [name_area]">
</asp:AccessDataSource>
</td>
</tr>
<tr>
<td>
<asp:TextBox runat="server" Text="חיפוש חופשי" ID="txtFreeText" Style="font-size: 12px;
height: 15px; width: 151px" />
<%--<input type="text" value="חיפוש חופשי" onfocus="deleteFreeText()" id="FreeText" name="FreeText"
style="font-size: 12px; height: 15px; width: 151px" runat="server" />--%>
<br />
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td align="right">
<asp:UpdatePanel ID="UpdatePanel2" runat="server" RenderMode="Inline" UpdateMode="Conditional">
<ContentTemplate>
<iframe id="Iframe1" runat="server" frameborder="0" name="Iframe1" scrolling="no"
width="360px" src="" style="overflow: auto"></iframe>
</ContentTemplate>
</asp:UpdatePanel>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
protected void Page_Load(object sender, EventArgs e)
{
TextBox tb = (TextBox)FindControl("txtFreeText");
tb.Attributes.Add("onfocus", "this.value = ''");
if (!Page.IsPostBack)
{
LoadProffesion();
}
}