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group:BuiltinProperties DirectCast Fails
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An unhandled exception of type 'System.InvalidCastException' occurred in resultsoutput.dll Additional information: Specified cast is not valid. In general terms the code is constructed as follows; ModuleA Public xlWb As Excel.Workbook ModuleB SubA Dim prps As Microsoft.Office.Core.DocumentProperties prps = DirectCast(xlWb.BuiltinDocumentProperties, Microsoft.Office.Core.DocumentProperties) This is using; Framework 1.1 Excel 2002 SP3 Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) I've been following the article by Ken Getz (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's article refers to Excel 2003, but all the objects he references are also in the Microsoft Excel 10 COM object. I wondered whether this was a bug in the 2002 COM or I've missed something in my code.
Try CType instead of DirectCast.
In this case, you're dealing with COM wrappers, and I have the nagging feeling you're using a newer interface and trying to cast directly to an older one. CType should call QueryInterface under the hood, so that if the interface exists, it will get you a proper reference. Hope that helps, -Rob Teixeira [MVP] [quoted text, click to view] "Mark Nethercott" <Mark.Nethercott@iFabre.com> wrote in message news:upRORNuLEHA.892@TK2MSFTNGP09.phx.gbl... > I get the following failure when trying to access the builtin properties; > > An unhandled exception of type 'System.InvalidCastException' occurred in > resultsoutput.dll > Additional information: Specified cast is not valid. > > In general terms the code is constructed as follows; > > ModuleA > Public xlWb As Excel.Workbook > > ModuleB > SubA > Dim prps As Microsoft.Office.Core.DocumentProperties > prps = DirectCast(xlWb.BuiltinDocumentProperties, > Microsoft.Office.Core.DocumentProperties) > > This is using; > Framework 1.1 > Excel 2002 SP3 > Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) > > I've been following the article by Ken Getz > (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 > 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's article > refers to Excel 2003, but all the objects he references are also in the > Microsoft Excel 10 COM object. I wondered whether this was a bug in the 2002 > COM or I've missed something in my code. > > >
Rob,
DirectCast will call QueryInterface to find the COM interface! I will be very curious if CType works, where DirectCast fails. Hope this helps Jay [quoted text, click to view] "Rob Teixeira [MVP]" <RobTeixeira@@msn.com> wrote in message news:%23Xn8hNyLEHA.3380@TK2MSFTNGP11.phx.gbl... > Try CType instead of DirectCast. > In this case, you're dealing with COM wrappers, and I have the nagging > feeling you're using a newer interface and trying to cast directly to an > older one. CType should call QueryInterface under the hood, so that if the > interface exists, it will get you a proper reference. > > Hope that helps, > > -Rob Teixeira [MVP] > > "Mark Nethercott" <Mark.Nethercott@iFabre.com> wrote in message > news:upRORNuLEHA.892@TK2MSFTNGP09.phx.gbl... > > I get the following failure when trying to access the builtin properties; > > > > An unhandled exception of type 'System.InvalidCastException' occurred in > > resultsoutput.dll > > Additional information: Specified cast is not valid. > > > > In general terms the code is constructed as follows; > > > > ModuleA > > Public xlWb As Excel.Workbook > > > > ModuleB > > SubA > > Dim prps As Microsoft.Office.Core.DocumentProperties > > prps = DirectCast(xlWb.BuiltinDocumentProperties, > > Microsoft.Office.Core.DocumentProperties) > > > > This is using; > > Framework 1.1 > > Excel 2002 SP3 > > Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) > > > > I've been following the article by Ken Getz > > > (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 > > 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's > article > > refers to Excel 2003, but all the objects he references are also in the > > Microsoft Excel 10 COM object. I wondered whether this was a bug in the > 2002 > > COM or I've missed something in my code. > > > > > > > >
Yes, you're absolutely right. That's what I get for posting while
multi-tasking *sigh* OK, this seems like a similar issue to a co-worker had. Try this Mark - Use reflection on the object reference you do have to get all implemented interfaces. Also use Reflection to get the GuidAttribute from each (including the GuidAttribute on the object ref's class). Next, check to see that these are in fact the registered interfaces for Excel in the system registry (based on the GUIDs). I believe the problem may in fact be that you are trying to cast to a newer version of the interface, which an older version of Excel might not provide (or another such scenario). It would also help to know what version of the PIAs you are using vs. what version of Office (and which PIAs have you installed on that system). -Rob Teixeira [MVP] [quoted text, click to view] "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message news:e7Tofs4LEHA.1392@TK2MSFTNGP09.phx.gbl... > Rob, > DirectCast will call QueryInterface to find the COM interface! > > I will be very curious if CType works, where DirectCast fails. > > Hope this helps > Jay > > "Rob Teixeira [MVP]" <RobTeixeira@@msn.com> wrote in message > news:%23Xn8hNyLEHA.3380@TK2MSFTNGP11.phx.gbl... > > Try CType instead of DirectCast. > > In this case, you're dealing with COM wrappers, and I have the nagging > > feeling you're using a newer interface and trying to cast directly to an > > older one. CType should call QueryInterface under the hood, so that if the > > interface exists, it will get you a proper reference. > > > > Hope that helps, > > > > -Rob Teixeira [MVP] > > > > "Mark Nethercott" <Mark.Nethercott@iFabre.com> wrote in message > > news:upRORNuLEHA.892@TK2MSFTNGP09.phx.gbl... > > > I get the following failure when trying to access the builtin > properties; > > > > > > An unhandled exception of type 'System.InvalidCastException' occurred in > > > resultsoutput.dll > > > Additional information: Specified cast is not valid. > > > > > > In general terms the code is constructed as follows; > > > > > > ModuleA > > > Public xlWb As Excel.Workbook > > > > > > ModuleB > > > SubA > > > Dim prps As Microsoft.Office.Core.DocumentProperties > > > prps = DirectCast(xlWb.BuiltinDocumentProperties, > > > Microsoft.Office.Core.DocumentProperties) > > > > > > This is using; > > > Framework 1.1 > > > Excel 2002 SP3 > > > Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) > > > > > > I've been following the article by Ken Getz > > > > > > (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 > > > 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's > > article > > > refers to Excel 2003, but all the objects he references are also in the > > > Microsoft Excel 10 COM object. I wondered whether this was a bug in the > > 2002 > > > COM or I've missed something in my code. > > > > > > > > > > > > > > >
Thanks for the suggestions. I'd already tried CType as an alternative, but
that fails as well. Ken Getz's article is pretty clear on working with the DirectCast - I'll try the code with the 2003 COM object [quoted text, click to view] "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message news:e7Tofs4LEHA.1392@TK2MSFTNGP09.phx.gbl... > Rob, > DirectCast will call QueryInterface to find the COM interface! > > I will be very curious if CType works, where DirectCast fails. > > Hope this helps > Jay > > "Rob Teixeira [MVP]" <RobTeixeira@@msn.com> wrote in message > news:%23Xn8hNyLEHA.3380@TK2MSFTNGP11.phx.gbl... > > Try CType instead of DirectCast. > > In this case, you're dealing with COM wrappers, and I have the nagging > > feeling you're using a newer interface and trying to cast directly to an > > older one. CType should call QueryInterface under the hood, so that if the > > interface exists, it will get you a proper reference. > > > > Hope that helps, > > > > -Rob Teixeira [MVP] > > > > "Mark Nethercott" <Mark.Nethercott@iFabre.com> wrote in message > > news:upRORNuLEHA.892@TK2MSFTNGP09.phx.gbl... > > > I get the following failure when trying to access the builtin > properties; > > > > > > An unhandled exception of type 'System.InvalidCastException' occurred in > > > resultsoutput.dll > > > Additional information: Specified cast is not valid. > > > > > > In general terms the code is constructed as follows; > > > > > > ModuleA > > > Public xlWb As Excel.Workbook > > > > > > ModuleB > > > SubA > > > Dim prps As Microsoft.Office.Core.DocumentProperties > > > prps = DirectCast(xlWb.BuiltinDocumentProperties, > > > Microsoft.Office.Core.DocumentProperties) > > > > > > This is using; > > > Framework 1.1 > > > Excel 2002 SP3 > > > Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) > > > > > > I've been following the article by Ken Getz > > > > > > (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 > > > 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's > > article > > > refers to Excel 2003, but all the objects he references are also in the > > > Microsoft Excel 10 COM object. I wondered whether this was a bug in the > > 2002 > > > COM or I've missed something in my code. > > > > > > > > > > > > > > >
Thanks Rob for the input.
You were right, in the end I had to use reflection to contort my way through the COM interface. It took a while to figure out & I relied heavily on the help of Tom Annetts @ Experts-Exchange. The full thread can be found at; http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/VB.NET/Q_20973995.html I've included the final function here for completeness. I've only tested it under XP SP3 & Excel 2002, where it works fine; Sub SetProperty(ByVal xlWB As Excel.Workbook, ByVal PName As String, ByVal PValue As Object, _ ByVal isPropCustom As Boolean) 'This function sets the value of a property. ' 'The parameters passed to the function are as follows: ' 'xlWB A reference to the the workbook whose property is to be set. 'PName A string containing the name of the property 'PValue A variant containing the value of the property 'isPropCustom A boolean indicating whether the property is a Custom Document Property. Dim result As Object Dim PType As Long Dim isLinkToContent As Boolean = False Dim LinkSource As Object = Nothing Select Case VarType(PValue) Case vbBoolean PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeBoolean Case vbDate PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeDate Case vbDouble, vbLong, vbSingle, vbCurrency PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeFloat Case vbInteger PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeNumber Case vbString PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeString Case Else PType = Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeString End Select If isPropCustom Then xlWB.CustomDocumentProperties.GetType().InvokeMember("Add", BindingFlags.InvokeMethod, _ Nothing, xlWB.CustomDocumentProperties, New Object() {PName, isLinkToContent, PType, PValue, LinkSource}) Else result = xlWB.BuiltinDocumentProperties.GetType().InvokeMember("Item", BindingFlags.GetProperty, _ Nothing, xlWB.BuiltinDocumentProperties, New Object() {PName}) result.GetType().InvokeMember("Value", BindingFlags.SetProperty, Nothing, result, New Object() {PValue}) End If End Sub [quoted text, click to view] "Rob Teixeira [MVP]" <RobTeixeira@@msn.com> wrote in message news:%23wIGUp6LEHA.3472@TK2MSFTNGP09.phx.gbl... > Yes, you're absolutely right. That's what I get for posting while > multi-tasking *sigh* > > OK, this seems like a similar issue to a co-worker had. > Try this Mark - Use reflection on the object reference you do have to get > all implemented interfaces. > Also use Reflection to get the GuidAttribute from each (including the > GuidAttribute on the object ref's class). > > Next, check to see that these are in fact the registered interfaces for > Excel in the system registry (based on the GUIDs). > I believe the problem may in fact be that you are trying to cast to a newer > version of the interface, which an older version of Excel might not provide > (or another such scenario). It would also help to know what version of the > PIAs you are using vs. what version of Office (and which PIAs have you > installed on that system). > > -Rob Teixeira [MVP] > > "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message > news:e7Tofs4LEHA.1392@TK2MSFTNGP09.phx.gbl... > > Rob, > > DirectCast will call QueryInterface to find the COM interface! > > > > I will be very curious if CType works, where DirectCast fails. > > > > Hope this helps > > Jay > > > > "Rob Teixeira [MVP]" <RobTeixeira@@msn.com> wrote in message > > news:%23Xn8hNyLEHA.3380@TK2MSFTNGP11.phx.gbl... > > > Try CType instead of DirectCast. > > > In this case, you're dealing with COM wrappers, and I have the nagging > > > feeling you're using a newer interface and trying to cast directly to an > > > older one. CType should call QueryInterface under the hood, so that if > the > > > interface exists, it will get you a proper reference. > > > > > > Hope that helps, > > > > > > -Rob Teixeira [MVP] > > > > > > "Mark Nethercott" <Mark.Nethercott@iFabre.com> wrote in message > > > news:upRORNuLEHA.892@TK2MSFTNGP09.phx.gbl... > > > > I get the following failure when trying to access the builtin > > properties; > > > > > > > > An unhandled exception of type 'System.InvalidCastException' occurred > in > > > > resultsoutput.dll > > > > Additional information: Specified cast is not valid. > > > > > > > > In general terms the code is constructed as follows; > > > > > > > > ModuleA > > > > Public xlWb As Excel.Workbook > > > > > > > > ModuleB > > > > SubA > > > > Dim prps As Microsoft.Office.Core.DocumentProperties > > > > prps = DirectCast(xlWb.BuiltinDocumentProperties, > > > > Microsoft.Office.Core.DocumentProperties) > > > > > > > > This is using; > > > > Framework 1.1 > > > > Excel 2002 SP3 > > > > Reference to COM Microsoft Excel 10.0 Object Library (Version 1.4) > > > > > > > > I've been following the article by Ken Getz > > > > > > > > > > (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_vsto20 > > > > 03_ta/html/ExcelObj.asp) which suggests the code should work. Ken's > > > article > > > > refers to Excel 2003, but all the objects he references are also in > the > > > > Microsoft Excel 10 COM object. I wondered whether this was a bug in > the > > > 2002 > > > > COM or I've missed something in my code. > > > > > > > > > > > > > > > > > > > > > > > >
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