0

Hello,

Any help will be much appreciated.

I have created a page tht will show search results on a datalist. this page was running perfectly before the addition of following lines in the page Load and BtnSearch_Click respectively.

            if (Request.QueryString["query"] != null)

            {

                string searchParam = Request.QueryString["query"].ToString();

                BindList(searchParam);

            }

....................................

        string qryString = Url;  //Request.Url.ToString();

        qryString += "?query=" + TxtSearch.Text.Trim();



        Response.Redirect(qryString);

            }

................................................

Now the problem is at lstSearch.DataBind();. It gives exception “String Value can not be null. Parameter name:Old value”. I googled the error but most of the ppl who encountered this problem were those who upgraded to newer versions of VS and thts not the case with me..

then I replaced the DataList with Repeater. It binds the data perfectly but it always picks zero index (shown in the following lines) , due to which I again the same exception at text replacement at the ItemDataBound event.

            int index = _strContent.IndexOf(TxtSearch.Text, StringComparison.OrdinalIgnoreCase);

            //Find substring with the help of that Index

            string sub_strContent = _strContent.Substring(index, TxtSearch.Text.Length);

            //Highlight the substring

            string _strHighlightText = "<span class=\"highlight\">" + sub_strContent + "</span>";

            //Replace the text with highlighted text

            _strContent = _strContent.Replace(sub_strContent, _strHighlightText);

...............................................

Below is the complete code.Note that I have also added pagin to my .aspx page.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;



namespace abc

{

    public partial class search_result : System.Web.UI.Page

    {

        PagedDataSource pageSource;

        //'currentpage' is used to keep track of the pages binded to the DataList

        public static int currentpage = 0;

        string Url ="search-result.aspx";



        protected void Page_Load(object sender, EventArgs e)

        {

            lbtnNext1.Visible = false;

            lbtnPrev1.Visible = false;

            if (!Page.IsPostBack)

            {

                lblResults1.Visible = false;

                lblResults2.Visible = false;

                lblResults3.Visible = false;

                if (Request.QueryString["query"] != null)

                {

                    string searchParam = Request.QueryString["query"].ToString();

                    BindList(searchParam);

                }

            }

        }

        protected void BtnSearch_Click(object sender, EventArgs e)

        {

            string qryString = Url;  //Request.Url.ToString();

            qryString += "?query=" + TxtSearch.Text.Trim();



            Response.Redirect(qryString);



            //if (TxtSearch.Text != null && TxtSearch.Text != string.Empty)

            //{ BindList(); }



            //else { }

        }

        protected void Item_Click(object sender, DataListCommandEventArgs e)

        {

            Response.Redirect(e.CommandName);

        }

        protected void lbtnPrev_Click(object sender, EventArgs e)

        {

           // currentpage -= 1;

            //BindList();

        }

        protected void lbtnNext_Click(object sender, EventArgs e)

        {

            //currentpage += 1;

            //BindList();

        }

        public void BindList(string search)

        {

            try

            {

                BLL.Admin adminobj = new BLL.Admin(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());

                DataSet ds = adminobj.Search(search);                

                int count = ds.Tables[0].Rows.Count;



                //Bind data to the DataList if matching results are found

                if (count != 0)

                {

                    lblResults1.Visible = true;

                    lblResults2.Visible = true;

                    lblResults3.Visible = false;

                    if (count == 1)

                    {

                        lblResults1.Text = count + " Result for ";

                        lblResults2.Text = TxtSearch.Text;

                    }

                    else

                    {

                        lblResults1.Text = count + " Results for ";

                        lblResults2.Text = TxtSearch.Text;

                    }

                    pageSource = new PagedDataSource();

                    pageSource.AllowPaging = true;

                    pageSource.DataSource = ds.Tables[0].DefaultView;



                    // Set the number of results to be displayed below.

                    //e.g if you want to display 10 results per page, replace 5 by 10.

                    int a = 5;

                    pageSource.PageSize = a;

                    pageSource.CurrentPageIndex = currentpage;



                   // Disable the linkbuttons if it is first or last page.

                    lbtnNext1.Enabled = !pageSource.IsLastPage;

                    lbtnPrev1.Enabled = !pageSource.IsFirstPage;



                    //Set the datasource for DataList

                    lstSearch.DataSource = ds.Tables[0].DefaultView;

                    lstSearch.DataSource = pageSource;

                    lstSearch.DataBind(); //gives exception here.



                   //  Keep the LinkButtons invisible if the returned rows are less than or equal to 5

                    if (count > a)

                    {

                        lbtnNext1.Visible = true;

                        lbtnPrev1.Visible = true;

                    }

                }

                else

                {

                    //Display a message if the search doesnot match any results

                    lblResults1.Visible = true;

                    lblResults2.Visible = true;

                    lblResults3.Visible = true;

                    lblResults1.Text = "No Results found for ";

                    lblResults2.Text = TxtSearch.Text;

                    lblResults3.Text= ". Make sure all words are spelled correctly.";

                    lstSearch.DataSource = pageSource;

                    lstSearch.DataBind();

                }

            }            

            catch (Exception ex)

            { Console.Write(ex.Message); }

        }



        protected void lstSearch_ItemDataBound(object sender, DataListItemEventArgs e)

        {

            if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)

            {

                Label lblContent = (Label)e.Item.FindControl("lblContent");

                string _strContent = lblContent.Text;

                //Get the index of entered word(s)

                int index = _strContent.IndexOf(TxtSearch.Text, StringComparison.OrdinalIgnoreCase);

                //Find substring with the help of that Index

                string sub_strContent = _strContent.Substring(index, TxtSearch.Text.Length);

                //Highlight the substring

                string _strHighlightText = "<span class=\"highlight\">" + sub_strContent + "</span>";

                //Replace the text with highlighted text

                _strContent = _strContent.Replace(sub_strContent, _strHighlightText);

                lblContent.Text = _strContent;

            }

        }

        protected void lstSearch_SelectedIndexChanged(object sender, EventArgs e)

        {



        }         

    }

}

 ........................................................................................................................

<div id="searchBox">
                            <asp:TextBox ID="TxtSearch" runat="server" Width="80%"></asp:TextBox>
                            &nbsp;<asp:Button ID="BtnSearch" runat="server" Text="Search" OnClick="BtnSearch_Click" />
                        </div>
                        <div id="DispalyLabel">
                            <br />
                            <asp:Label ID="lblResults1" runat="server" Text=" "></asp:Label><asp:Label ID="lblResults2"
                                runat="server" Text="Label" Font-Bold="true"></asp:Label><asp:Label ID="lblResults3" runat="server"
                                    Text=" "></asp:Label>
                        </div>
                        <br />
                        <br />
                        <asp:DataList ID="lstSearch" runat="server" OnItemCommand="Item_Click" HorizontalAlign="Justify"
                            ShowHeader="true" Width="100%" CssClass="searchResult" 
                            onitemdatabound="lstSearch_ItemDataBound" 
                            onselectedindexchanged="lstSearch_SelectedIndexChanged">
                            <AlternatingItemStyle BackColor="White" ForeColor="#333333" />
                            <ItemStyle BackColor="#F7F6F3" ForeColor="#333333" />
                            <ItemTemplate>
                                <table width="100%" cellpadding="5" cellspacing="0" border="0">
                                <tr>
                                <td>
                                <h4>
                                <asp:HyperLink ID="HyperLink1" Target="_blank" NavigateUrl='<%# "~/" + DataBinder.Eval(Container.DataItem,"PageName")%>'
                                Text='<%# DataBinder.Eval(Container.DataItem,"Page_Title")%>' runat="server"></asp:HyperLink></h4>
                                </td>
                                </tr>
                                <tr>
                                <td>
                                <asp:Label ID="lblContent" runat="server" Font-Bold="false" Text='<%# (DataBinder.Eval(Container.DataItem,"HTML_Content"))%>'></asp:Label>
                                </td>
                                </tr>
                                <tr>
                                <td>
                                <asp:HyperLink ID="HyperLink2" Target="_blank" NavigateUrl='<%# "~/" + DataBinder.Eval(Container.DataItem,"PageName")%>'
                                        Text='<%# DataBinder.Eval(Container.DataItem,"PageName")%>' runat="server"></asp:HyperLink>
                                </td>
                                </tr>
                                </table>
                            </ItemTemplate>
                            <SelectedItemStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                        </asp:DataList>
                        <div id="LinkButton">
                            <table>
                            <tr><td>  </td></tr>
                                <tr>
                                    <td align="left">
                                        <asp:LinkButton ID="lbtnPrev1" runat="server" OnClick="lbtnPrev_Click" ForeColor="Black">Prev</asp:LinkButton>
                                    </td>
                                    <td align="right">
                                        <asp:LinkButton ID="lbtnNext1" runat="server" OnClick="lbtnNext_Click" ForeColor="Black">Next</asp:LinkButton>
                                    </td>
                                </tr>                              
                            </table>
                        </div>

Edited by Dani: Formatting fixed

1
Contributor
1
Reply
2
Views
5 Years
Discussion Span
Last Post by ariez88
0

Caught the culprit.
i added try-catch block to ItemDataBound and came to know tht the TxtSearch was containing null after the page was being redirected to itself. Hence I set the value of searchParam to TxtSearch and it worked. :)

This question has already been answered. Start a new discussion instead.
Have something to contribute to this discussion? Please be thoughtful, detailed and courteous, and be sure to adhere to our posting rules.