下拉列表框中内容无法保留

Question

我在做保存的时候，有两个下拉列表框，在第一步的时候我都两个下拉列表框中的内容都进行了选择，在保存结束后有一个按钮，也就是第二张图片，点击的时候能够返回到刚刚先去保存操作的步骤，可是这个时候两个下拉列表框中的内容居然复原了，我想要它仍然显示我先前选择的内容，求大神帮忙啊！！！
下拉列表框中内容无法保存返回值无效

Answer 1

你填充数据的代码在哪，如果是在pageload事件中，加上 ispostback的判断，这样保证只填充 一次

Answer 2

  <asp:DropDownList ID="ddlTemplates" runat="server" AutoPostBack="true" Style="width: 400px;
                        font-size: 20px;" OnSelectedIndexChanged="ddlTemplates_SelectedIndexChanged"
                        AppendDataBoundItems="true">
                        <asp:ListItem Text="-" Value="" Selected="True">
                        </asp:ListItem>
                    </asp:DropDownList><asp:DropDownList ID="ddlLeadGroup" runat="server" Style="background: none repeat scroll 0 0 #EAF2F4;
                                    width: 400px; font-size: 20px;" AppendDataBoundItems="true">
                                    <asp:ListItem Text="-" Value="" Selected="True">
                                    </asp:ListItem>
                                </asp:DropDownList>
 private void BindTemplates()
    {
        ddlTemplates.DataSource = SellSimilarItem.GetTemplates((int)MemberID);
        ddlTemplates.DataTextField = "TemplateName";
        ddlTemplates.DataValueField = "TemplateID";
        ddlTemplates.DataBind();
    }
    private void BindLeadGroup(int LeadGroupID)
    {
        ddlLeadGroup.Items.Clear();
        ddlLeadGroup.Items.Add(new ListItem("Select Group ", ""));
        ddlLeadGroup.DataSource = LeadsGroup.Select((int)MemberID);
        ddlLeadGroup.DataTextField = "LeadsGroupName";
        ddlLeadGroup.DataValueField = "LeadsGroupID";
        ddlLeadGroup.DataBind();
        if (LeadGroupID != 0)
        {
            Utils.Common.setSelectedValue(LeadGroupID.ToString(), ddlLeadGroup);
        }
    } protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            if (User.Identity.IsAuthenticated)
            {
                UserID = Managers.Users.UserID;                Models.UsereBayAuthToken token = Managers.UsereBayAuthToken.Get(UserID);
                if (token != null)
                {
                    if (token.HardExpirationTime > DateTime.Now)
                    {
                        eBayAuthToken = token.eBayAuthToken;
                        ucItemSpecifics.eBayToken = token.eBayAuthToken;
                        Member member = Members.findByEmailAddress(User.Identity.Name);
                        if (member != null)
                        {
                            MemberID = member.MemberID;
                            txtPayPalEmailAddress.Text = member.PaypalID;
                            txtLocation.Text = member.eBayLocation;
                            GetSkuCounterString();                           
                            if (tmpLeadID == 0)
                            {
                                tmpLeadID = new Random().Next(100000000, 999999999);
                            }                            if (member.eBayLaunchItem != null)
                            {
                                eBayLaunchItem = member.eBayLaunchItem.Value;
                                if (member.eBayLaunchItem.Value)
                                {
                                    ShoweBayPanels(null, null);
                                }
                                else
                                {
                                    HideeBay(null, null);
                                }
                            }                            // select all Buyer Requirements by default
                            br.LinkedPayPalAccount = br.MaximumUnpaidItemStrikesInfo = br.ShipToRegistrationCountry =
                            br.MaximumBuyerPolicyViolations = br.RequireMinimumFeedbackScore =
                            br.MaximumItemRequirements = br.MaximumItemRequirementsMinimumFeedbackScore = true;                            // set Quantity On Hand = 1, by default
                            txtQuantityOnHand.Text = "1";                            if ((!string.IsNullOrEmpty(Request.QueryString["ssi"])) && (Request.QueryString["ssi"] == "t"))
                            {
                                if (!string.IsNullOrEmpty(Request.QueryString["act"]) && (Request.QueryString["act"] == "clone"))
                                {
                                    if (Session["cloneItem"] != null)
                                    {
                                        SellSimilarItem template = Session["cloneItem"] as SellSimilarItem;
                                        ForSellSimilarItem(template);
                                        pTemplates.Visible = false;
                                        isClone = true;
                                        foreach (LeadFile lf in template.LeadFile)
                                        {
                                            Managers.LeadFiles.Insert(tmpLeadID, "", lf.FileName, "");
                                        }
                                    }
                                }
                                else if (!String.IsNullOrEmpty(Request.QueryString["act"]) && Request.QueryString["act"] == "editTemplate")
                                {
                                    if (!string.IsNullOrEmpty(Request.QueryString["tid"]))
                                    {
                                        List<SellSimilarItem> temps = SellSimilarItem.GetTemplates(TemplateID, Convert.ToInt32(MemberID));
                                        if (temps != null && temps.Count > 0)
                                        {
                                            SellSimilarItem template = temps[0];
                                            ForSellSimilarItem(template);
                                            tbNewTemplateName.Text = template.TemplateName;
                                            pTemplates.Visible = false;
                                            ptemplateName.Visible = true;
                                            ClientScript.RegisterStartupScript(this.GetType(), "hidden", "<script>document.getElementById('btnContinue_show').style.display='none';</script>");
                                            btnUpdate.Visible = true;
                                            lbtnContinueTop.Visible = false;
                                            lbtnContinueBottom.Visible = false;
                                            lbtnSaveCloseTop.Visible = false;
                                            lbtnSaveCloseBottom.Visible = false;
                                            lbtnCancelTop.Visible = false;
                                            lbtnCancelBottom.Visible = false;
                                        }
                                    }
                                }
                                else
                                {
                                    if (Session["SimilarItem"] != null)
                                    {
                                        SellSimilarItem template = Session["SimilarItem"] as SellSimilarItem;
                                        ForSellSimilarItem(template);
                                    }
                                }
                                BindTemplates();
                                BindLeadGroup(0);
                            }
                            else if (Session["DefaultTemplate"] != null)
                            {
                                BindTemplates();
                                SellSimilarItem defaultTemplate = (SellSimilarItem)Session["DefaultTemplate"];
                                cbDefaultTemplate.Checked = true;
                                ddlTemplates.Items.FindByValue("").Selected = false;
                                ddlTemplates.Items.FindByValue(defaultTemplate.TemplateID.ToString()).Selected = true;
                                ForSellSimilarItem(defaultTemplate);
                            }
                            else
                            {
                                BindTemplates();
                                BindLeadGroup(0);
                            }
                            lbtnSaveCloseTop.Visible = false;
                            lbtnSaveCloseBottom.Visible = false;                        }
                        else
                        {
                            Close();
                        }
                    }
                    else
                    {
                        Sigin();
                    }
                }
                else
                {
                    Sigin();
                }
            }
            else
            {
                Close();
            }
        }
        else
        {
            lblLeadQuality.Text = txtLeadQualityText.Text;
            ucItemSpecifics.CategoryID = eBayCategoryID.ToString();
            if (!String.IsNullOrEmpty(Request.QueryString["act"]) && Request.QueryString["act"] == "editTemplate")
            {
                if (!string.IsNullOrEmpty(Request.QueryString["tid"]))
                {
                    ClientScript.RegisterStartupScript(this.GetType(), "hidden", "<script>document.getElementById('btnContinue_show').style.display='none';</script>");

Answer 3

在给下拉框绑定数据之前先clear一下

Answer 4

clear？我这个需要的实现的功能说白了就是在刷新页面后先前选中的下拉列表框中的内容还在，如果用clear那不是给它归位了吗？

Answer 5

我在他的后台代码中把这个给注释了，可是在注释结束后他的选择Select Group却无法显示了
而且前台HTml中的Select Group也无法使用
<asp:DropDownList ID="ddlLeadGroup" runat="server" Style="background: none repeat scroll 0 0 #EAF2F4;
                                    width: 400px; font-size: 20px;" AppendDataBoundItems="true">
                                    <asp:ListItem Text="Select Group" Value="" Selected="True">
                                    </asp:ListItem>
                                </asp:DropDownList>
private void BindLeadGroup(int LeadGroupID)
    {
        ddlLeadGroup.Items.Clear();
        //ddlLeadGroup.Items.Add(new ListItem(" ", ""));
        ddlLeadGroup.DataSource = LeadsGroup.Select((int)MemberID);
        ddlLeadGroup.DataTextField = "LeadsGroupName";
        ddlLeadGroup.DataValueField = "LeadsGroupID";
        ddlLeadGroup.DataBind();
        if (LeadGroupID != 0)
        {
            Utils.Common.setSelectedValue(LeadGroupID.ToString(), ddlLeadGroup);
        }
    }