Problem in Cascading dropdown

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Hi all,

I am new to ajax and i was trying to use cascading dropdown but getting some error.my code is as below.

------------webservice.cs-------------

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Data.SqlClient;
using System.Data;
using System.Collections.Specialized;

/// <summary>
/// Summary description for WebService
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
 [System.Web.Script.Services.ScriptService]
public class WebService : System.Web.Services.WebService
{
    public string str = (@"server=PRINCE\MSSQLSERVER1;database=centuryDB;integrated security=true;");
    //public WebService()
    //{

    //    //Uncomment the following line if using designed components
    //    //InitializeComponent();
    //}

    [WebMethod]
    public AjaxControlToolkit.CascadingDropDownNameValue[] GetDropDownCategories(string knownCategoryValues, string category)
    {
        SqlConnection sqlConn = new SqlConnection(str);
        sqlConn.Open();
        SqlCommand sqlSelect = new SqlCommand("SELECT country_id,Country FROM country_detail", sqlConn);
        sqlSelect.CommandType = System.Data.CommandType.Text;
        SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlSelect);
        DataSet myDataset = new DataSet();
        sqlAdapter.Fill(myDataset);
        sqlConn.Close();

        List<AjaxControlToolkit.CascadingDropDownNameValue> cascadingValues = new List<AjaxControlToolkit.CascadingDropDownNameValue>();

        foreach (DataRow dRow in myDataset.Tables[0].Rows)
        {
            string categoryID = dRow["country_id"].ToString();
            string categoryName = dRow["Country"].ToString();
            cascadingValues.Add(new AjaxControlToolkit.CascadingDropDownNameValue(categoryName, categoryID));
        }

        return cascadingValues.ToArray();
    }
    [WebMethod]
    public AjaxControlToolkit.CascadingDropDownNameValue[] GetDropDownProducts(string knownCategoryValues, string category)
    {
        int categoryID;

        StringDictionary categoryValues = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

        categoryID = Convert.ToInt32(categoryValues["country"]);

        SqlConnection sqlConn = new SqlConnection(str);
        sqlConn.Open();
        SqlCommand sqlSelect = new SqlCommand("SELECT state_id,State FROM state_detail where country_id = @country_id", sqlConn);
        sqlSelect.CommandType = System.Data.CommandType.Text;
        sqlSelect.Parameters.Add("@country_id", SqlDbType.Int).Value = categoryID;
        SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlSelect);
        DataSet myDataset = new DataSet();
        sqlAdapter.Fill(myDataset);
        sqlConn.Close();

        List<AjaxControlToolkit.CascadingDropDownNameValue> cascadingValues = new List<AjaxControlToolkit.CascadingDropDownNameValue>();

        foreach (DataRow dRow in myDataset.Tables[0].Rows)
        {
            string productID = dRow["state_id"].ToString();
            string productName = dRow["State"].ToString();
            cascadingValues.Add(new AjaxControlToolkit.CascadingDropDownNameValue(productName, productID));
        }

        return cascadingValues.ToArray();

    }

}

-----------default.aspx code is-------------

ASP.NET

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" 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>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ToolkitScriptManager ID="ScriptManager1" runat="server">
        </asp:ToolkitScriptManager>
        <table>
        <tr>
        <td>select country:
        <asp:DropDownList ID="ddlcountry" runat="server"></asp:DropDownList>
        </td>
        <td>
            <asp:CascadingDropDown ID="CascadingDropDown1" runat="server" Category="country"  TargetControlID="ddlcountry"
            PromptText="[Select Category]"
            LoadingText="Loading categories..."
            ServicePath="~/WebService.asmx"
            ServiceMethod="GetDropDownCategories">
            </asp:CascadingDropDown>
        </td>
        <td>Select state:
        <asp:DropDownList ID="ddlstate" runat="server" ></asp:DropDownList>
        </td>
        <td>
            <asp:CascadingDropDown ID="CascadingDropDown2" runat="server" Category="state" TargetControlID="ddlstate"
            ParentControlID="ddlcountry"
            PromptText="Select ...."
            LoadingText="Loading....."
            ServicePath="~/WebService.asmx"
            ServiceMethod="GetDropDownProducts">
            </asp:CascadingDropDown>
        </td>
        <td><asp:Button ID="btnok" Text="ok" runat="server" onclick="btnok_Click" /></td>
        <td><asp:Label ID="lblresult" runat="server"></asp:Label></td>
        </tr>

        </table>

    </div>
    </form>
</body>
</html>

Can you please help me how to solve this.

Posted 3-Sep-11 1:23am

preetpal kapoor

Updated 3-Sep-11 1:26am

Wendelius

v2

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Comments

Abhinav S 3-Sep-11 7:25am

What error? You have provided a lot of code but not mentioned where or what the error is.
Try debugging through your source code.

Abhijit Jana 3-Sep-11 15:23pm

Hey Abhinav. Here is the comments . Moved in comments so that you can get a notification.
--------
hi Abhinav,

The error is as follows when i press the ok button on my form

-------------------------------------------------
Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
----------------------------------------------------

please help me in this.
----------------------------

1 solution

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

preetpal kapoor · Answer 1 · 2011-09-03T08:07:00

hi Abhinav,

The error is as follows when i press the ok button on my form

-------------------------------------------------
Invalid postback or callback argument. Event validation is enabled using <pages enableeventvalidation="true"> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
----------------------------------------------------

please help me in this.

Problem in Cascading dropdown

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Problem in Cascading dropdown

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