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If your tab pages are in a different namespace, then you need to import that namespace using the using Namespace; statement like you do with every other class.
Microsoft MVP, Visual C#
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the project is called 'Patriot' so all namespaces are the same as the classes have been created in the same project
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The project name doesn't mean anything, except that the default root namespace is the project name. If you use folders in your project, source files added to those folders are defaulted to the root namespace plus the folder name(s) appended in hierarchical order. Just look at the source files to see what namespace they're in.
Also, do not make a namespace for each separate class! C'mon, think about it. Does each control in System.Windows.Forms have a separate namespace? No, they're all grouped into that namespace. Namespaces are there to logically group classes and other members, just like System includes all the ubiquitous stuff, and System.Data includes all the core ADO.NET classes, and System.Web includes all the core ASP.NET class while System.Web.UI.WebControls includes a bunch of web controls.
If your current class is in a different namespace, then you must import all namespaces that are different - regardless of whether or not they're in your current project! - or you must type in their fully-qualified type name (namespace + class/interface/struct/enum name).
Microsoft MVP, Visual C#
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what source files are you talking about? im working hard on the namespaces as icant see it yet
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The files that contain your source code.
Microsoft MVP, Visual C#
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yes and they all are using the same namespace ie 'patriot' the problem is only there for my tabpages and when i look at my new tabpage in the deign view the controls look a mess, but comes out perfect when i run the project
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i know you are very busy man, but i hope you have not deserted me
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ive checked and there is only on namespace, but i have lots of errors like
method not found
operation is not valid
the variable fixedsingle is either undeclared or was never used
etc
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Then go through the errors by double-clicking them to go to the line with the error and fix them.
Microsoft MVP, Visual C#
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when i create my tabpage i added an ordinary class and not a component class will that cause me problems? as it works ok when i run the project
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As I said before, your class has to derive from TabPage. It doesn't matter how you added the file - you could've added a simple text file and then changed the name to Something.cs for all VS.NET cares, so long as you change the Build Action to "Compile". I even gave you an example of how to declare your class, which I'll type here again:
public class MyTabPage : TabPage
{
}Whatever namespace those are in must be imported into the class file that uses them, otherwise the classes can't be found, just like you have to import the System.Windows.Forms namespace so that TabPage can be found, otherwise you have to type the fully-qualified namespace EVERY TIME you reference a class, struct, interface, or enumeration.
Microsoft MVP, Visual C#
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i should be able to capture the text in my class when an instance is created then all my database logic can be contained in my class very nice only need to write it once. cheers for the boot in the buttocks
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Hi all,
I m making an application in C# with compact framework. I need to get data from one form to another without making them public static or even without passing like form form1 = new form(variables).......
Any other options....
BE Computer Engineer from India.
Working on C# and Dot net technologies......
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One suggestion: Create a third class to hold this data. Then from each of the forms reference the instance of the class that you set up to hold/manage the data.
Does this help?
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
Coming soon: The Second EuroCPian Event[^].
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Hi,
I have read about reflections, seems to be a cool thing... but It's seems more oriented to do case tools than other things ? Am I Wrong ? Some people says me that it's used on huge projects... but I think all that thing of calling "Invoke" and things like that remembers me to the IDispatch nightmare and GUIDS and ... 
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Reflection is definitely useful for case tools, but it can be used in production code, although the size of the project doesn't matter. For instance, reflection is used by the runtime and XML serialization routines. Reflection could also be used - while not recommended - to get/set a private field in a class if you really need to (its name could be changed at any time, though, which is one reason it's not recommended). You could use reflection to discover type information at runtime, which makes it a good solution in many things like IDispatch interfaces, although reflection is much easier to use, IMO, than dispatch (just less things you have to do to accomplish the same thing, which is pretty universal comparing .NET to lower-level languages like C and C++).
Microsoft MVP, Visual C#
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I have an app which uses an ActiveX component. No problmes there. I have now converted it to run as a windows service, which also work fine when i configure the service to run using my NT Login account. However, when i configure the service to run using the System Account, i get an exception:
System.IO.FileNotFoundException: The specified module could not be found.
when the code tried to instantiate the ActiveX control.
I have the Path to the Dll in the system environment. Does any one have any ideas?
Thanks
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With ActiveX, the PATH environment variable doesn't really matter (it can, but is not typically necessary, because...). When an ActiveX control is registered, it's server's path (the executable that contains the control) is registered in the Windows registry under HKEY_CLASS_ROOT\CLSID. This is one thing that makes COM so attractive - you don't have to worry about where the file is (thus helping to eliminate DLL hell, so long as you follow good COM guidelines about interface naming and the like).
Make sure the ActiveX DLL (or OCX or whatever) is registered correctly using regsvr32.exe.
The other possibility is that the interop assembly was not found. When you import an ActiveX control (or even a typelib) interop assemblies are generated, which are also called Runtime Callable Wrappers, or RCWs. Those assemblies must be either in the same directory as the service executable, in the probing path (configurable in the .config file, which must also be in the same directory as the service executable and named the same as the executable + ".config"), using the <assemblyBinding> section in your .config file, or installed into the Global Assembly Cache (GAC), which requires that the assembly be signed (it's easy, just use sn.exe -k KeyFile.snk to generate a key pair).
Microsoft MVP, Visual C#
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We have a strange problem in equating string and BSTR between a ATL server and c# client.
I have given a similar sample below.
What am i doing wrong?
c# client
=====
AirlineInfoObjClass _aobj=new AirlineInfoObjClass();
string _time=_aobj.GetAirlineTiming("IC5678");
Console.WriteLine("The timing is {0}", _time);
ATL DLL
=====
STDMETHODIMP CAirlineInfoObj::GetAirlineTiming(BSTR bstrAirline, BSTR *pbstrDetails)
{
// TODO: Add your implementation code here
USES_CONVERSION;
BSTR m_Airline=SysAllocString(L"IC5678");
if(m_Airline == bstrAirline)
{
*pbstrDetails = SysAllocString (L"16:45:00 - Will arrive at Terminal 3");
}
else
{
// Return the Airline name if not found
*pbstrDetails = bstrAirline;
}
return S_OK;
}
The above always returns me the airline name,while theoretically it should return the "16:45:00........" message.Can someone help?
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This is an error in your C++ code. The == operator on BSTRs does a pointer comparison (since BSTR is a typedef for unsigned short*). Use wcscmp.
Stability. What an interesting concept. -- Chris Maunder
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Yes. And also make sure pbstrDetails is marked as [out, retval] in your IDL.
Sincerely,
-Ron
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We are in the process of converting ATL clients to C#.
However,I have not been able to make errors to get progated properly.
I have read that teh ATL component is reqired to support the ISupportErrorInfo interface for erro propagation to work.
Subsquently here is the point where error is raised from a ATL dll
else
{
CreateErrorInfo(&pErrorInfo);
if(hSuccess)
{
pErrorInfo->SetGUID(IID_IAirlineInfoObj);
pErrorInfo->SetDescription(SysAllocString(L"Data not found"));
IErrorInfo* _errInfo=NULL;
hSuccess=pErrorInfo->QueryInterface(IID_IErrorInfo,(void**)&_errInfo);
if(hSuccess)
{
SetErrorInfo(0,_errInfo);
}
}
return E_FAIL;
}
And the C# client tries to trap it as follows
catch(Exception e)
{
Console.WriteLine( " The exception is {0}",System.Runtime.InteropServices.Marshal.GetHRForException(e));
}
This does not work.How do i retrieve the data I had set on the IErrorInfo interface in the COM server?
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What exactly doesn't work? The runtime should throw a System.Runtime.InteropServices.COMException when your COM component returns an E_FAIL error code, unless you've used the PreserveSig attribute. Visual Studio and the tlbimp tool default to throwing exceptions for COM error codes.
The message and help information you specified in the ErrorInfo object should be present in the Message, HelpLink and Source properties of the COMException object.
You may find the ATL function AtlReportError easier to deal with than handling the error info object directly.
Stability. What an interesting concept. -- Chris Maunder
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Hi guys! Im using a third party external type library (C API) currently running in VB6. This is a low-level COM so it can't be converted to MSIL code nor it can be reference as COM inside a C# app. What I did is call this as an unmanaged code thru Platform Invoke. Most of the methods/functions were working fine except for some where it returns an exception of System.NullReferenceException. I found out that the method i called calls another method (with parameters) from a Module. However VB.Net and C# doesn't support this upgrade? Is this true? Then how do i go around with this? What other options can I resort to? I really have to CALL those methods/functions in my project because its the main core of my app logic process. Pls advise. Tnx!
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Can I clarify? You're using a DLL with flat exports from VB6 using the Declare statement, and it calls back into your VB program (you pass function pointers into the DLL using the VB AddressOf syntax)?
You're probably getting access violations (the CLR converts an access violation SEH exception into a System.NullReferenceException managed exception) because you haven't initialised the callback function pointers.
To get a callback from unmanaged into managed code, you need to use a delegate. See MSDN: Implementing Callback Functions[^].
Stability. What an interesting concept. -- Chris Maunder
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