Listview with Search and DataPager controls - asp.net

Question

As this is my first project, I really do not have much idea to debug this. I have a listview. I am writing code manually to populate listview. As the listview is very large, I have a search button where user enters a search string. I am trying to build a sql string from here and populate the listview. Everything works fine but when I click on next page, it does not include the search string. I think it is just populating the 2nd page without the search criteria. If I remove the data pager control, it works fine. I am not able to put proper code datapger_PagePropertiesChanging. I appreciate if someone can help me with this.
Here is my list view markup:
<asp:ListView ID="lvContractors" runat="server" OnPagePropertiesChanging="lvContractors_PagePropertiesChanging">
<LayoutTemplate>
<div class="ListViewGrid">
<table class="tblpadding">
<tr>
<th class="HeaderStyle">
Contractor Number
</th>
<th class="HeaderStyle">
First Name
</th>
<th class="HeaderStyle">
Last Name
</th>
<th class="HeaderStyle">
View
</th>
<th class="HeaderStyle">
Edit
</th>
</tr>
<tbody><asp:PlaceHolder runat="server" ID="itemPlaceholder" /></tbody>
</table>
</div> <!-- End of ListViewGrid -->
</LayoutTemplate>
<ItemSeparatorTemplate> <td> <hr /> </td>
</ItemSeparatorTemplate>
<ItemTemplate>
<div >
<tr>
<td class="RowStyle"><%#Eval("ContractorNumber")%></td>
<td class="RowStyle"><%#Eval("FirstName")%></td>
<td class="RowStyle"><%#Eval("LastName")%></td>
<td class="RowStyle">
<asp:HyperLink ID="lnkView" runat="server" CssClass="link"
NavigateUrl='<%# "ContractorEdit.aspx?ID=" + Eval("ContractorNumber") + "&Mode=" + "CV" %>'
Target="_blank" Text="View" />
</td>
<td class="RowStyle">
<asp:HyperLink ID="lnkEdit" runat="server" CssClass="link"
NavigateUrl= '<%# "ContractorEdit.aspx?ID=" + Eval("ContractorNumber") + "&Mode=" + "CE" %>'
Text="Edit"> </asp:HyperLink>
</tr>
</div>
</ItemTemplate>
<AlternatingItemTemplate>
<div>
<tr>
<td class="AlternatingRowStyle"><%#Eval("ContractorNumber")%></td>
<td class="AlternatingRowStyle"><%#Eval("FirstName")%></td>
<td class="AlternatingRowStyle"><%#Eval("LastName")%></td>
<td class="AlternatingRowStyle">
<asp:HyperLink ID="lnkView" runat="server" CssClass="link"
NavigateUrl='<%# "Contractor.aspx?ID=" + Eval("ContractorNumber")%>'
Target="_blank" Text="View" />
</td>
<td class="AlternatingRowStyle">
<asp:HyperLink ID="lnkEdit" runat="server" CssClass="link"
NavigateUrl= '<%# "ContractorEdit.aspx?ID=" + Eval("ContractorNumber") + "&Mode=" + "CE" %>'
Text="Edit"> </asp:HyperLink>
</tr>
</div>
</AlternatingItemTemplate>
<ItemSeparatorTemplate>
<tr>
<td colspan="5" class="itemseparator"></td>
</tr>
</ItemSeparatorTemplate>
</asp:ListView>
<div class="pager">
<asp:DataPager PageSize="20" ID="DataPagerContractor" runat="server" PagedControlID="lvContractors"
NextPreviousButtonCssClass="PrevNext"
CurrentPageLabelCssClass="CurrentPage"
NumericButtonCssClass="PageNumber">
<fields>
<asp:NumericPagerField
PreviousPageText="< Prev"
NextPageText="Next >"
ButtonCount="10"
NextPreviousButtonCssClass="PrevNext"
CurrentPageLabelCssClass="CurrentPage"
NumericButtonCssClass="PageNumber" />
</fields>
</asp:DataPager>
</div>
</div> Code behind this: Partial Class Contractor
Inherits System.Web.UI.Page
Private txtKeywordSearchWhereClause As String = ""
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
Session("Clicked") = "Contractor"
End If
If Not DBNull.Value.Equals(txtKeywordSearchWhereClause) Then
LoadContractors(txtKeywordSearchWhereClause)
Else
LoadContractors("")
End If
End Sub
Private Sub LoadContractors(ByVal strSearch As String)
Dim strConn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("Conn").ConnectionString)
strConn.Open()
Dim sql As String = "SELECT * FROM tblContractor1"
If Not strSearch = "" Then
sql = sql & strSearch
sql = sql & " ORDER BY LastName"
End If
Dim da As SqlDataAdapter = New SqlDataAdapter(sql, strConn)
Dim dt As DataTable = New DataTable()
da.Fill(dt)
lvContractors.DataSource = dt
lvContractors.DataBind()
End Sub
Protected Sub buttonAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles buttonAdd.Click
Response.Redirect("ContractorEdit.aspx", False)
End Sub
Protected Sub btnSearch_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSearch.Click
' Keyword Search
Dim txtKeywordSearch As String = txtSearch.Text
Dim txtWhereClause As String = ""
If txtKeywordSearch.Trim() <> "" Then
txtWhereClause = " WHERE FirstName LIKE '%" + txtKeywordSearch + "%'"
txtWhereClause = txtWhereClause + " OR LastName LIKE '%" + txtKeywordSearch + "%'"
txtWhereClause = txtWhereClause + " OR ContractorNumber LIKE '%" + txtKeywordSearch + "%'"
txtKeywordSearchWhereClause = txtWhereClause
End If
LoadContractors(txtKeywordSearchWhereClause)
End Sub
Protected Sub lvContractors_PagePropertiesChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.PagePropertiesChangingEventArgs) Handles lvContractors.PagePropertiesChanging
DataPagerContractor.SetPageProperties(e.StartRowIndex, e.MaximumRows, False)
'rebind List View
If Not DBNull.Value.Equals(txtKeywordSearchWhereClause) Then
LoadContractors(txtKeywordSearchWhereClause)
Else
LoadContractors("")
End If
End Sub
End Class

Answer 1

Sorry to say, but this is not possible with the datapager (at least in ASP.Net 3.5).
The only solution is to write your own pager from scratch as the only querystring parameter the datapager can pass is the page number.