我在登陆页面设了个选择主题的下拉框，预设了两个主题，分别是蓝色和红色，根据我下拉框的选项时时跟换主题
代码是这样子的
- C# code
protected void Page_Preinit(object sender,EventArgs e) { HttpCookie theme = Request.Cookies["Theme"]; if (theme == null) { this.Theme = "blue"; } else { this.Theme = theme.Value; } } protected void Page_Load(object sender, EventArgs e) { if(!IsCallback) { HttpCookie theme = Request.Cookies["Theme"]; if (theme != null) { string themestring = theme.Value; for (int i = 0; i < this.DropDownList1.Items.Count; i++) { if (this.DropDownList1.Items[i].Value == themestring) { this.DropDownList1.SelectedIndex = i; } } } } } protected void DropDownList1_SelectedIndexChanged1(object sender, EventArgs e) { Response.Cookies["Theme"].Value = this.DropDownList1.SelectedValue; Response.Redirect("login.aspx"); }第一次页面加载的时候。因为Request.Cookies["Theme"];为空，所以主题是蓝色，然后我在下拉框内选择红色的时候，方法还是会先经过Page_Preinit（object sender, EventArgs e）这时Request.Cookies["Theme"];依然为空。然后到Page_Load(object sender, EventArgs e)再到DropDownList1_SelectedIndexChanged1(object sender, EventArgs e)我在这存了一个Cookies，页面重新加载。主题会变为红色，
问题来了，当我再选择蓝色的时候，主题依然会是红色，不会变。这怎么解决啊？
------解决方案--------------------------------------------------------
if (!Page.IsPostBack)
{
BindGrid();
}
这样就不会再次执行了