I had an aspx.net project where I needed to generate a pdf.
I used crystal to do the heavy lifting of geneating the pdf for me.
But as I needed to deploy it to multiple databases/clients I needed a way of programmatically changing the datasource location of the report. So with a bit of help from the crystal knowledgebase here is the code I use.
There is a lot of debugging information in here and trust me when it fails you need it.
The .dbo of the location reference obviously means I was working with sql server.

   1  
   2     ' --------------------------------------------------------------------------
   3     ' SetupReport
   4     '
   5     ' Description:
   6     '    sets up the crystal report
   7     '
   8     ' Arguments:
   9     '    objCrystalReportDocument             - crystal report document object
  10     '
  11     ' Dependencies:
  12     '    GetConnnectionInfo
  13     '    CrystalDescisions
  14     '
  15     ' History:
  16     ' 03/17/2006 - WSR : created
  17     '
  18     Private Function SetupReport(ByRef objCrystalReportDocument As CrystalDecisions.CrystalReports.Engine.ReportDocument) As System.Boolean
  19  
  20        ' a heck of a lot of objects used
  21        Dim crParameterDiscreteValue As CrystalDecisions.Shared.ParameterDiscreteValue
  22        Dim crParameterFieldDefinitions As CrystalDecisions.CrystalReports.Engine.ParameterFieldDefinitions
  23        Dim crParameterFieldLocation As CrystalDecisions.CrystalReports.Engine.ParameterFieldDefinition
  24        Dim crParameterValues As CrystalDecisions.Shared.ParameterValues
  25        Dim crSections As CrystalDecisions.CrystalReports.Engine.Sections
  26        Dim crSection As CrystalDecisions.CrystalReports.Engine.Section
  27        Dim crReportObjects As CrystalDecisions.CrystalReports.Engine.ReportObjects
  28        Dim crReportObject As CrystalDecisions.CrystalReports.Engine.ReportObject
  29        Dim crSubreportDocument As CrystalDecisions.CrystalReports.Engine.ReportDocument
  30        Dim crSubreportObject As CrystalDecisions.CrystalReports.Engine.SubreportObject
  31        Dim crConnectionInfo As CrystalDecisions.Shared.ConnectionInfo
  32        Dim crDatabase As CrystalDecisions.CrystalReports.Engine.Database
  33        Dim crTables As CrystalDecisions.CrystalReports.Engine.Tables
  34        Dim aTable As CrystalDecisions.CrystalReports.Engine.Table
  35        Dim bTable As CrystalDecisions.CrystalReports.Engine.Table
  36        Dim crTableLogOnInfo As CrystalDecisions.Shared.TableLogOnInfo
  37        Dim blnTest As System.Boolean
  38        Dim strLocation As System.String
  39        Dim blnErrors As System.Boolean
  40  
  41        ' instantiate the debug page
  42        m_strDebugPage = New System.Text.StringBuilder(4096)
  43        blnErrors = False
  44  
  45        crConnectionInfo = GetConnectionInfo()
  46  
  47        crDatabase = objCrystalReportDocument.Database
  48  
  49        crTables = crDatabase.Tables
  50  
  51        'For intCounter = 0 To objCrystalReportDocument.Database.Tables.Count - 1
  52        For Each aTable In crTables
  53  
  54           crTableLogOnInfo = aTable.LogOnInfo
  55  
  56           OutputDebugLine("BEFORE")
  57           OutputDebugLine("TABLE NAME: " & aTable.Name)
  58           OutputDebugLine("TABLE LOC: " & aTable.Location)
  59           OutputDebugLine("SERVER: " & crTableLogOnInfo.ConnectionInfo.ServerName)
  60           OutputDebugLine("DB: " & crTableLogOnInfo.ConnectionInfo.DatabaseName)
  61           OutputDebugLine("UID: " & crTableLogOnInfo.ConnectionInfo.UserID)
  62           OutputDebugLine("PWD: " & crTableLogOnInfo.ConnectionInfo.Password)
  63           OutputDebugLine("RN: " & crTableLogOnInfo.ReportName)
  64           OutputDebugLine("TN: " & crTableLogOnInfo.TableName)
  65  
  66           crTableLogOnInfo.ConnectionInfo = crConnectionInfo
  67           aTable.ApplyLogOnInfo(crTableLogOnInfo)
  68           strLocation = crConnectionInfo.DatabaseName & ".dbo." & aTable.Location.Substring(aTable.Location.LastIndexOf(".") + 1)
  69           OutputDebugLine("New Location: " & strLocation)
  70           Try
  71              aTable.Location = strLocation
  72           Catch ex As Exception
  73              OutputDebugLine("Set Location Error: " & ex.ToString)
  74              blnErrors = True
  75           End Try
  76  
  77           OutputDebugLine("AFTER")
  78           OutputDebugLine("TABLE NAME: " & aTable.Name)
  79           OutputDebugLine("TABLE LOC: " & aTable.Location)
  80           OutputDebugLine("SERVER: " & crTableLogOnInfo.ConnectionInfo.ServerName)
  81           OutputDebugLine("DB: " & crTableLogOnInfo.ConnectionInfo.DatabaseName)
  82           OutputDebugLine("UID: " & crTableLogOnInfo.ConnectionInfo.UserID)
  83           OutputDebugLine("PWD: " & crTableLogOnInfo.ConnectionInfo.Password)
  84           OutputDebugLine("RN: " & crTableLogOnInfo.ReportName)
  85           OutputDebugLine("TN: " & crTableLogOnInfo.TableName)
  86           Try
  87              blnTest = aTable.TestConnectivity()
  88              OutputDebugLine("CONNECTED? " & blnTest.ToString())
  89           Catch ex As Exception
  90              OutputDebugLine("CONNECTED? NO")
  91              OutputDebugLine(ex.ToString)
  92              blnErrors = True
  93           End Try
  94  
  95           '// THIS STUFF HERE IS FOR REPORTS HAVING SUBREPORTS 
  96           '// set the sections object to the current report's section 
  97           crSections = objCrystalReportDocument.ReportDefinition.Sections
  98  
  99           '// loop through all the sections to find all the report objects 
 100           For Each crSection In crSections
 101  
 102              crReportObjects = crSection.ReportObjects
 103  
 104              '//loop through all the report objects in there to find all subreports 
 105              For Each crReportObject In crReportObjects
 106  
 107                 If crReportObject.Kind = ReportObjectKind.SubreportObject Then
 108  
 109                    crSubreportObject = CType(crReportObject, CrystalDecisions.CrystalReports.Engine.SubreportObject)
 110                    '//open the subreport object and logon as for the general report 
 111                    crSubreportDocument = crSubreportObject.OpenSubreport(crSubreportObject.SubreportName)
 112                    crDatabase = crSubreportDocument.Database
 113                    crTables = crDatabase.Tables
 114  
 115                    For Each bTable In crTables
 116  
 117                       crTableLogOnInfo = bTable.LogOnInfo
 118  
 119                       OutputDebugLine("BEFORE")
 120                       OutputDebugLine("TABLE NAME: " & bTable.Name)
 121                       OutputDebugLine("TABLE LOC: " & bTable.Location)
 122                       OutputDebugLine("SERVER: " & crTableLogOnInfo.ConnectionInfo.ServerName)
 123                       OutputDebugLine("DB: " & crTableLogOnInfo.ConnectionInfo.DatabaseName)
 124                       OutputDebugLine("UID: " & crTableLogOnInfo.ConnectionInfo.UserID)
 125                       OutputDebugLine("PWD: " & crTableLogOnInfo.ConnectionInfo.Password)
 126                       OutputDebugLine("RN: " & crTableLogOnInfo.ReportName)
 127                       OutputDebugLine("TN: " & crTableLogOnInfo.TableName)
 128  
 129                       crTableLogOnInfo.ConnectionInfo = crConnectionInfo
 130                       bTable.ApplyLogOnInfo(crTableLogOnInfo)
 131                       strLocation = crConnectionInfo.DatabaseName & ".dbo." & bTable.Location.Substring(bTable.Location.LastIndexOf(".") + 1)
 132                       OutputDebugLine("New Location: " & strLocation)
 133                       Try
 134                          bTable.Location = strLocation
 135                       Catch ex As Exception
 136                          OutputDebugLine("Set Location Error: " & ex.ToString)
 137                          blnErrors = True
 138                       End Try
 139  
 140                       OutputDebugLine("AFTER")
 141                       OutputDebugLine("TABLE NAME: " & bTable.Name)
 142                       OutputDebugLine("TABLE LOC: " & bTable.Location)
 143                       OutputDebugLine("SERVER: " & crTableLogOnInfo.ConnectionInfo.ServerName)
 144                       OutputDebugLine("DB: " & crTableLogOnInfo.ConnectionInfo.DatabaseName)
 145                       OutputDebugLine("UID: " & crTableLogOnInfo.ConnectionInfo.UserID)
 146                       OutputDebugLine("PWD: " & crTableLogOnInfo.ConnectionInfo.Password)
 147                       OutputDebugLine("RN: " & crTableLogOnInfo.ReportName)
 148                       OutputDebugLine("TN: " & crTableLogOnInfo.TableName)
 149                       Try
 150                          blnTest = bTable.TestConnectivity()
 151                          OutputDebugLine("CONNECTED? " & blnTest.ToString())
 152                       Catch ex As Exception
 153                          OutputDebugLine("CONNECTED? NO")
 154                          OutputDebugLine(ex.ToString)
 155                          blnErrors = True
 156                       End Try
 157  
 158                    Next bTable
 159  
 160                 End If
 161  
 162              Next crReportObject
 163  
 164           Next crSection
 165  
 166        Next aTable
 167  
 168        ' get parameter fields from report
 169        crParameterFieldDefinitions = objCrystalReportDocument.DataDefinition.ParameterFields
 170  
 171        '    ' Set the first parameter
 172        '    ' - Get the parameter, tell it to use the current values vs default value.
 173        '    ' - Tell it the parameter contains 1 discrete value vs multiple values.
 174        '    ' - Set the parameter's value.
 175        '    ' - Add it and apply it.
 176        '    ' - Repeat these statements for each parameter.
 177        '    '
 178        crParameterFieldLocation = crParameterFieldDefinitions.Item("@psindex")
 179        crParameterValues = crParameterFieldLocation.CurrentValues
 180        crParameterDiscreteValue = New CrystalDecisions.Shared.ParameterDiscreteValue
 181        crParameterDiscreteValue.Value = m_intReportID
 182        crParameterValues.Add(crParameterDiscreteValue)
 183        crParameterFieldLocation.ApplyCurrentValues(crParameterValues)
 184  
 185        ' if there were errors
 186        If blnErrors Then
 187  
 188           ' display debug page
 189           OutputDebugPage()
 190  
 191        End If
 192  
 193     End Function
 194     ' --------------------------------------------------------------------------
 195  
 196  
 197     ' --------------------------------------------------------------------------
 198     ' GetConnectionInfo
 199     '
 200     ' Description:
 201     '    retrieves the connection information from the data layer object
 202     '
 203     ' Arguments: none
 204     '
 205     ' Dependencies:
 206     '    DataLayer.GetConnectInfo
 207     '
 208     ' History:
 209     ' 03/17/2006 - WSR : created
 210     '
 211     Private Function GetConnectionInfo() As CrystalDecisions.Shared.ConnectionInfo
 212  
 213        Dim objConnectionInfo As CrystalDecisions.Shared.ConnectionInfo
 214        Dim strDSN As System.String
 215        Dim strDB As System.String
 216        Dim strUID As System.String
 217        Dim strPWD As System.String
 218        Dim blnTrust As System.Boolean
 219  
 220        ' get connection information from data layer
 221        m_objDataLayer.GetConnectInfo(strDSN, strDB, strUID, strPWD, blnTrust)
 222  
 223        ' create new crystal connection info object
 224        objConnectionInfo = New CrystalDecisions.Shared.ConnectionInfo
 225  
 226        ' populate it
 227        objConnectionInfo.IntegratedSecurity = False
 228        objConnectionInfo.ServerName = strDSN
 229        objConnectionInfo.UserID = strUID
 230        objConnectionInfo.Password = strPWD
 231        objConnectionInfo.DatabaseName = strDB
 232  
 233        ' return object
 234        GetConnectionInfo = objConnectionInfo
 235  
 236     End Function
 237     ' --------------------------------------------------------------------------
 238  
 239     ' --------------------------------------------------------------------------
 240     ' OutputDebugLine
 241     '
 242     ' Description: appends a line to the debug string builder
 243     '
 244     ' Arguments: text to add
 245     '
 246     ' Dependencies:
 247     '    m_strDebugPage
 248     '
 249     ' History:
 250     ' 03/17/2006 - WSR : created
 251     ' 2007.04.25 - WSR : revised to use string builder
 252     '
 253     Function OutputDebugLine(ByVal strLine As System.String) As System.Boolean
 254  
 255        m_strDebugPage.Append("<div>" & Server.HtmlEncode(strLine) & "</div>")
 256  
 257     End Function
 258     ' --------------------------------------------------------------------------
 259  
 260  
 261     ' --------------------------------------------------------------------------
 262     ' OutputDebugPage
 263     '
 264     ' Description: sends debug string builder to response
 265     '
 266     ' Arguments: none
 267     '
 268     ' Dependencies:
 269     '    m_strDebugPage
 270     '
 271     ' History:
 272     ' 2007.04.25 - WSR : created
 273     '
 274     Function OutputDebugPage() As System.Boolean
 275  
 276        With Response
 277           .ClearHeaders()
 278           .ClearContent()
 279           .ContentType = "text/html"
 280        End With
 281  
 282        Response.Write("<html><head><title>Debug Page</title></head><body>")
 283        Response.Write(m_strDebugPage.ToString())
 284        Response.Write("</body></html>")
 285  
 286        Response.Flush()
 287        Response.End()
 288  
 289     End Function
 290     ' --------------------------------------------------------------------------
 291  
 292