response.write出来的窗口为什么要点两次确定？

Question

    在formview中我设置了一个CustomValidator控件，当验证为通过时，会弹出“合同号已存在！”的错误提示窗口。
    奇怪的是，现在窗口会弹出来两次，也就是要我点两下弹出窗口的“确定”才行，这该怎么解决啊？

    下面是可能相关的2部分代码，请大家帮忙看看，谢谢！

-----------------------------前台----------------------------

<asp:FormView ID="FormView1" runat="server" DataKeyNames="CID" 
                        DataSourceID="SqlDataSource_FormView"  HorizontalAlign="Center" 
                        BorderColor="#CCCCCC">

<asp:CustomValidator ID="CustomValidator_ContractNumber" runat="server" 
                                             Font-Size="10px" 
                                            onservervalidate="CustomValidator_ContractNumber_ServerValidate" 
                                            Display="Dynamic" ErrorMessage="合同号已存在"></asp:CustomValidator>

</asp:FormView>

-------------------------后台---------------------------

protected void Page_Load(object sender, EventArgs e)
    {

        if (!IsPostBack)
        {
            if (Session["UName"].ToString() != "ccc")
            {
                Response.Redirect("~/index.htm");
            }
            else
            {
                Session.Timeout = 30;
                string str1 = ((Label)this.FormView1.FindControl("Label_Pic")).Text;
                //Response.Write(str1);
                if (str1 != "")
                {
                    ((HyperLink)this.FormView1.FindControl("HyperLink_Pic")).NavigateUrl = "~/Pictures/ContractPic\\" + str1;
                }
                else
                {
                    ((HyperLink)this.FormView1.FindControl("HyperLink_Pic")).NavigateUrl = "~/indexnull.htm";

                }

            }
        }

    }



protected void CustomValidator_ContractNumber_ServerValidate(object source, ServerValidateEventArgs args)
    {
        string strconn = "Data Source=.;Initial Catalog=长铁物业公司资产数据库;Integrated Security=True";
        SqlConnection cn = new SqlConnection(strconn);
        cn.Open();
        //string strConditionLabel = ((Label)this.FormView1.FindControl("ContractNumberLabel")).Text;
        string strContractNumber = ((TextBox)this.FormView1.FindControl("ContractNumberTextBox")).Text;
        string strCID = ((Label)this.FormView1.FindControl("CIDLabel")).Text;
        string strSearch = "BEGIN TRAN UPDATE ContractTable  SET ContractNumber='" + strContractNumber  + "' WHERE CID=" + strCID + " IF  ( SELECT  COUNT(*) FROM ContractTable WHERE ContractNumber='" + strContractNumber + "' ) <2 BEGIN ROLLBACK TRAN  SELECT '1' END ELSE BEGIN ROLLBACK TRAN SELECT '0' END";
        //Response.End();
        //取sql事务的结果，1或者0
        SqlCommand comm = new SqlCommand(strSearch, cn);
        string strResult = comm.ExecuteScalar().ToString();
        if (strResult == "1")
        { args.IsValid = true; }
        else
        {
            args.IsValid = false;
            Response.Write("<script language=javascript>alert('合同号已存在！');</script>");
        }
        cn.Close();
    }

---

C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 1

Response.Write("<script language=javascript>alert('合同号已存在'));

这一句删除——因为没有必要，CustomerValidation会自己验证，一旦设置IsValid=false，则自动弹出ErrorMessage的东西。

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Answer 2

    谢谢解答！

    您说的这个方法是可行，但是我现在需要它弹出一个窗口来重点提示，所以还是想找到只要点一次的方法才最好！

---

C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 3

把这个控件的Text设置为"*"，然后删除"ErrorMessage"属性，
注意我代码最下面if……部分：

protected void CustomValidator_ContractNumber_ServerValidate(object source, ServerValidateEventArgs args)
    {
        string strconn = "Data Source=.;Initial Catalog=长铁物业公司资产数据库;Integrated Security=True";
        SqlConnection cn = new SqlConnection(strconn);
        cn.Open();
        //string strConditionLabel = ((Label)this.FormView1.FindControl("ContractNumberLabel")).Text;
        string strContractNumber = ((TextBox)this.FormView1.FindControl("ContractNumberTextBox")).Text;
        string strCID = ((Label)this.FormView1.FindControl("CIDLabel")).Text;
        string strSearch = "BEGIN TRAN UPDATE ContractTable  SET ContractNumber='" + strContractNumber  + "' WHERE CID=" + strCID + " IF  ( SELECT  COUNT(*) FROM ContractTable WHERE ContractNumber='" + strContractNumber + "' ) <2 BEGIN ROLLBACK TRAN  SELECT '1' END ELSE BEGIN ROLLBACK TRAN SELECT '0' END";
        //Response.End();
        //取sql事务的结果，1或者0
        SqlCommand comm = new SqlCommand(strSearch, cn);
        string strResult = comm.ExecuteScalar().ToString();
        if (strResult != "1")
        {
               Response.Write("<script language=javascript>alert('合同号已存在！');</script>");
        }
        args.IsValid = (strResult=="1");
       cn.Close();

---

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Answer 4

    谢谢解答，但是问题依旧！我觉得这不是if语句引起的问题，而是服务器做出了两次反应！

---

C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 5

    谢谢解答，但是问题依旧！我觉得这不是if语句引起的问题，而是服务器做出了两次反应！

---

C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

是不是服务器做出了两次反应，你可以用 Fiddler 抓包分析，同时你可以通过 IE 的调试功能看下最终页面的源码。

Answer 6

    谢谢解答，但是问题依旧！我觉得这不是if语句引起的问题，而是服务器做出了两次反应！

除了以上代码，你有没有启用Client（脚本检查）？

有没有写过一些脚本验证的代码？

---

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Answer 7

很奇怪哦！我还有其他的控件，但只有这个控件是自定义判断的。

    我尝试用validationSummary，其他的验证控件都能弹出错误提示窗口，唯独这个CustomValidator没反应，不能弹出窗口，但可以正确执行验证。

这个问题号奇怪啊！

    也没什么脚本验证！

---

C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 8

CustomerValidation可以设定是否客户端验证，如果要和服务端的那边联系，恐怕需要要异步机制。不过我可以给你演示用服务端代码弹出对话框：

public partial class Default : System.Web.UI.Page
    {
         protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
        {
            //必须为1
            if (args.Value != "1")
            {
                ClientScript.RegisterStartupScript(GetType(), "s", "alert('必须为1!');", true);
                args.IsValid = false;
            }
        }
    }

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Answer 9

    您真是一语中的啊！问题解决了！

    

ClientScript.RegisterStartupScript以后就都用它了，Response老是奇奇怪怪的出问题！

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！