http:\/\/gotreportviewer.com\/<\/a> and look for the section on "supplying RDLs as a stream".\n<\/p>\n\nWhen we're all done building it, we're going to be calling this report twice, once to preprocess and once to provide results to the user. The PreProcess<\/strong> parameter tells the report which mode it's supposed to operate in. This boolean has the default value true<\/strong>.\n<\/p>\n\nFinally, you see an ExportType <\/strong>parameter. This string has the default value "HTML"<\/strong>, with "PDF"<\/strong> being the other value currently accepted by my code. This is required to handle differences between rendering types that may sequence things differently. \n<\/p>\n\nFWIW this technique was much, much simpler to prepare when I wasn't working with the PDF renderer, the HTML renderer's sequencing was fine but the PDF renderer couldn't "see" my activities in the order I expected. Much head-scratching ensued, followed by much more code than the original.\n<\/p>\n
\nIf you're curious, here are the principle differences: \n<\/p>\n
\n- The original code opened a file for writing at the beginning of the preprocess report run, appended to it throughout the run, and closed it at the end. Seems reasonable, doesn't it? But the pattern-of-use I experienced with the PDF Rendered indicated that this was not a great idea. Things seemed to be happening out of order. As a result, when preprocessing, you'll see that I open and close the file on every "hit". Oh well.
\n\tThis is another problem you might not have when persisting to a database rather than a file — or you might find that something similar happens if you try to hold onto a connection throughout the run.<\/li>\n - You'll see a PDFRunCount variable in this code. What's that about? It turns out that, at least when I invoked the PDF Renderer through URL Access, there were two sets of page numbers begin recorded; one for an internal HTML run and the other for the actual PDF pagination. I may have done something terminally stupid here, but in this code I'm making sure to record only the correct values, using this indicator.<\/li>\n<\/ul>\n
Now, about that code.<\/h4>\n
\nHere is the set of variables declared up-top in the custom code. Some are used to keep track of things internally, like PDFRunCount. But these variables can also be used directly in report expressions; you can see me doing that with Trim(Code.currentgroup)<\/strong> in the page header report expression, above.\n<\/p>\n\n Public<\/span> Shared<\/span> offset As<\/span> Integer<\/span> = 0
\n Public<\/span> Shared<\/span> currentgroup As<\/span> String<\/span>
\n Public<\/span> Shared<\/span> previousgroup As<\/span> String<\/span>
\n Public<\/span> Shared<\/span> groupNo As<\/span> Integer<\/span> = 0
\n Public<\/span> Shared<\/span> fileName As<\/span> String<\/span>
\n Public<\/span> Shared<\/span> PDFRunCount As<\/span> Integer<\/span> = 0
\n Dim<\/span> sw As<\/span> System.IO.StreamWriter
\n Dim<\/span> doc As<\/span> System.Xml.XmlDocument\n<\/p>\n\nHere's the first function, which collects group information, returns the current group's page number, and persists data between the runs so that the second run has group page totals. It looks alarming, but actually it's pretty straightforward. \n<\/p>\n
\nWhere you see "c:\\temp" for a file path below, you will want to make sure you are looking at a path that your report code has permissions to write — wherever that is, is okay (and again this would be irrelevant if you persist to a database).\n<\/p>\n
\n Public<\/span> Function<\/span> GetGroupPageNumber(ByVal<\/span> group As<\/span> String<\/span>, _
\n ByVal<\/span> pagenumber As<\/span> Integer<\/span>, ByVal<\/span> total As<\/span> Integer<\/span>, ByVal<\/span> filekey As<\/span> String<\/span>, _
\n ByVal<\/span> preprocess As<\/span> Boolean<\/span>, ByVal<\/span> exporttype As<\/span> String<\/span>) As<\/span> Object<\/span>
\n Try<\/span>
\n If<\/span> pagenumber = 1 Then<\/span>
\n groupNo = 0
\n currentgroup = ""<\/span>
\n offset = 0
\n If<\/span> exporttype = "PDF"<\/span> Then<\/span>
\n PDFRunCount += 1
\n End<\/span> If<\/span>
\n End<\/span> If<\/span>
\n If<\/span> Not<\/span> (group = currentgroup) AndAlso<\/span> PDFRunCount <> 1 Then<\/span>
\n If<\/span> groupNo = 0 Then<\/span>
\n ' fileName = System.IO.Path.GetTempPath() & _<\/span>
\n fileName = "c:\\temp\\"<\/span> & _
\n filekey & ".xml"<\/span> 'System.IO.Path.DirectorySeparatorChar &<\/span>
\n If<\/span> preprocess AndAlso<\/span> pagenumber = 1 Then<\/span>
\n sw = New<\/span> System.IO.StreamWriter(fileName, False<\/span>)
\n sw.WriteLine("<root>"<\/span>)
\n sw.Close()
\n sw.Dispose()
\n sw = Nothing<\/span>
\n End<\/span> If<\/span>
\n ElseIf<\/span> preprocess Then<\/span>
\n sw = New<\/span> System.IO.StreamWriter(fileName, True<\/span>)
\n sw.WriteLine( _
\n "<Group current='"<\/span> & currentgroup & _
\n "' lastPage='"<\/span> & CStr<\/span>(pagenumber – 1) & "'\/>"<\/span>)
\n sw.Close()
\n sw.Dispose()
\n sw = Nothing<\/span>
\n End If<\/span>
\n groupNo += 1
\n offset = pagenumber – 1
\n previousgroup = currentgroup
\n currentgroup = group
\n End<\/span> If<\/span>
\n If<\/span> (pagenumber = total AndAlso<\/span> preprocess) Then<\/span>
\n sw = New<\/span> System.IO.StreamWriter(fileName, True<\/span>)
\n sw.WriteLine( _
\n "<Group current='"<\/span> & currentgroup & _
\n "' lastPage='"<\/span> & CStr<\/span>(total) & "'\/>"<\/span>)
\n sw.WriteLine("<\/root>"<\/span>)
\n sw.Close()
\n sw.Dispose()
\n sw = Nothing<\/span>
\n End<\/span> If<\/span>
\n Return<\/span> pagenumber – offset
\n Catch<\/span> Ex As<\/span> Exception
\n Return<\/span> Ex.Message()
\n End<\/span> Try<\/span>
\n End<\/span> Function<\/span>\n<\/p>\n\nBesides creating the current page number for group as its result, the function creates an output file that looks like this:\n<\/p>\n
\n<root>
\n <Group current="Central Africa" lastPage="2" \/>
\n <Group current="Eastern Africa" lastPage="6" \/>
\n <Group current="Northern Africa" lastPage="7" \/>
\n <Group current="Southern Africa" lastPage="8" \/>
\n <Group current="Western Africa" lastPage="12" \/>
\n <Group current="Eastern Asia" lastPage="14" \/>
\n <Group current="Middle East" lastPage="16" \/>
\n <!– etc –>
\n<\/root>\n<\/p>\n
\nBesides creating the current page number for group as its result, as you can see above, the function is also kind enough to tell you what went wrong by returning information about the error instead of a page number. That's why it returns Object instead of anything else. The report engine is kind enough, in return, to manage the cast for you. This is an invaluable practice; please take note for other hacky techniques no matter what you are doing.\n<\/p>\n
\nHere's the code for function #2. This one (very straightforward) only has to work during the second run. During the first run, as you can see from the report expression above, this function is not invoked, and the word "[PreProcess Run]" is displayed instead. You can see this in the report preview window, if you leave the PreProcess parameter value set at its default of true.<\/strong> ![\"\"](\"\/lisa\/wp-non\/migrated\/preview.png\" "\\"See")
<\/a>\n<\/p>\n\n Function<\/span> ReadGroupPageTotal(ByVal<\/span> total) As<\/span> Object<\/span>
\n Dim<\/span> g As<\/span> String<\/span>, xa As<\/span> System.Xml.XmlAttribute, thisLastPage As<\/span> Integer<\/span>
\n Try<\/span>
\n If<\/span> doc Is<\/span> Nothing<\/span> Then<\/span>
\n doc = New<\/span> System.Xml.XmlDocument()
\n doc.Load(fileName)
\n End<\/span> If<\/span>
\n If<\/span> doc Is<\/span> Nothing<\/span> Then<\/span>
\n g = "NO DATA"<\/span>
\n Else<\/span>
\n xa = doc.SelectSingleNode( _
\n "\/root\/Group[@current='"<\/span> & currentgroup & "']\/@lastPage"<\/span>)
\n If<\/span> xa Is<\/span> Nothing<\/span> Then<\/span>
\n g = "NO DATA"<\/span>
\n ElseIf<\/span> groupNo = 1 Then<\/span>
\n g = xa.Value
\n Else<\/span>
\n thisLastPage = CInt<\/span>(xa.Value)
\n xa = doc.SelectSingleNode( _
\n "\/root\/Group[@current='"<\/span> & previousgroup & "']\/@lastPage"<\/span>)
\n If<\/span> xa Is<\/span> Nothing<\/span> Then<\/span>
\n g = "NO DATA"<\/span>
\n Else<\/span>
\n g = (thisLastPage – CInt<\/span>(xa.Value))
\n End<\/span> If<\/span>
\n If<\/span> thisLastPage = total Then<\/span>
\n doc = Nothing<\/span>
\n ' could clean up file here<\/span>
\n End<\/span> If<\/span>
\n End<\/span> If<\/span>
\n End<\/span> If<\/span>
\n Catch<\/span> Exc As<\/span> Exception
\n g = " error reading: "<\/span> & Exc.Message()
\n End<\/span> Try<\/span>
\n Return<\/span> g
\nEnd<\/span> Function<\/span>\n<\/p>\n\nThis code is using System.Xml. Depending on your method of persistence, you may have to provide an explicit reference to the appropriate assembly or assemblies. You do this in the Report Properties<\/strong> dialog, References <\/strong>tab. I'm using pretty basic functionality here, and I don't need to provide any class information in the dialog, just the assembly information. <\/a>\n<\/p>\nNow for the publishing<\/h4>\n
\nNow you just have to get this technique to work on the server. As explained earlier, you'll want to make sure you're writing to an "acceptable" location when you create your XML file or, if you're writing to a database, that you've provided appropriate credentials for your connection. Other than that, deploying this report should be pretty much like deploying any other report you've written… except for one thing.\n<\/p>\n
\nYou also have to make sure that your code has permissions to perform the requisite actions. This is one part that is definitely more sensible to do in a custom DLL, because you can add the permissions in a much more "targeted" way. Because I'm doing this example completely in custom code, I need to issue a "blanket" permission for custom code in report expressions, I can't target it more accurately than that.\n<\/p>\n
\nTo do this, you have to change something in the rssrvpolicy.config file (you'll find it in your Reporting Services\\ReportServer webapp home directory). You'll find a code group that looks something like this:\n<\/p>\n
\n<CodeGroup class="UnionCodeGroup" version="1"
\n PermissionSetName="Execution"
\n Name="Report_Expressions_Default_Permissions"
\n Description=
\n "This code group grants default permissions for code in report expressions and Code element. ">
\n …\n<\/p>\n
\n… and, if you are following this walkthrough exactly as written, you'll need to change the PermissionSetName attribute value you see above from Execution<\/strong> to