shorten load time for xml file

[milecimm]

Hi

I have the below code. It works fine but it takes a long time to load on the browser page. Is there anything I can do to shorten this time?

Also, I would like to search the file for documents with NAME starting with A, B, C, etc. How do I do that?

Thanks for your help!

aspx.vb page

Dim xdoc As New XPathDocument(xt)
       

        Dim nav As XPathNavigator = xdoc.CreateNavigator()

        Dim expr As XPathExpression
        expr = nav.Compile("/pf:CONTRACTS/pf:CONTRACT")

        Dim namespaceManager As XmlNamespaceManager = New XmlNamespaceManager(nav.NameTable)
        namespaceManager.AddNamespace("pf", "http://namespace/")

 	expr.SetContext(namespaceManager)

        Dim nodes As XPathNodeIterator = nav.Select(expr)

	If nodes.Count <> 0 Then

            Dim tr As String = Nothing
          
            For Each node As XPathNavigator In nodes

  		tr += "<td><a Target='_blank' href='http://www.urltosite.aspx?contract=" & node.SelectSingleNode("pf:ID", namespaceManager).Value & "'>" & node.SelectSingleNode("pf:NAME", namespaceManager).Value & "</a></td>"

 		For Each subNode2 As XPathNavigator In node.Select("pf:SUPPLIERS/pf:SUPPLIER", namespaceManager)

                    tr += "<td>" & subNode2.SelectSingleNode("pf:SUPPLIERNAME", namespaceManager).Value & "</td>"

                Next

                tr += "<td>" & node.SelectSingleNode("pf:ENDDATE", namespaceManager).Value & "</td>"

                tr += "</tr>"

            Next

            Dim th As String = "<th width='50%'>Name</th><th width='30%'>Supplier</th><th width='20%'>End Date</th>"

            div1.InnerHtml = ("<table width='96%' border='0' cellpadding='0' cellspacing='0' border='0' class='datatable1'>" & th) + tr & "</table>"

        Else

            div1.InnerHtml = "No results for your search"

        End If

aspx page

<div id="div1" runat="server" >   </div>

[jkmyoung]

I think the biggest problem is the string concatenation, eg using += or &. It's probably used thousands of times.

Everytime a concatenation operator is used, the string containing the results so far is resized, and possibly reallocated/copied/destroyed. Try and estimate the size of your output beforehand by using node counts, and allocate a stringbuilder object accordingly.

tips:
Create your own string concat object
VB StringBuilder class

Further question: Are you allowed to expose the source data to your clients?

[milecimm]

Hi

Thank you very much. I will use your idea.

Sorry, what do you mean with to be "allowed to expose the source data to your clients".

I am new at .net and xml and any help will be appreciated.

[jkmyoung]

There were some other methods I could think of, which would have needed client access to your source data, but on further investigation, they're much slower.