Importing virtual functions from a Dll

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  - 1
    - view data in a collection while debugging? I can see the data in datasets with the visualizer. With collections I get a datatip that allows me to expand and expand and expand but I can never find the data. Is there an easy way to view data in a collection object while debugging Tag: Importing virtual functions from a Dll
  - 2
    - creating collection property I'm not very sure that your explanation and especially thread name is describing the problem that you have. Are you seaching for way, how to have a property which in property window when changed, will have a drop down button which when clicked will show a list of posible values. If this is the case, then if you define a enum type with all posible values, and if you declare that your property is of that enum type, then you authomatically will get this functionality. Tag: Importing virtual functions from a Dll
  - 3
    - Visual Studio installation files Hi, Please, I am trying to install Visual Studio 2005, but i receive error 1311 - '_15690_RTL_x86_enu_MM_Setup_Files_VS_STD.cab' file is missing. Please can any one send the file Regards, Benjamin Tag: Importing virtual functions from a Dll
  - 4
    - Finalize data CD using XPBurn Thanks for the clarification. It makes much sense now. Yes XPBurn was a project on gotdotnet which uses the IMAPI engine. Did you try out the suggestion gvien by Lee. I do not have the xpburn project anymore with me, but I would look at the RecordDisc method and override/extend it to achieve the funtionality i desire. Tag: Importing virtual functions from a Dll
  - 5
    - Using a #define statement Is there a way to store multiple variables in a #definestatement I'd like to have a defined "backcolor" for my background color. The color is set with the (R,G,B) setting. is there a way to have a #define statement such as #define backcolor (r,g,b) where r,g,b are ints within the range of accecptable values if not, what would be a good alternative insteadad of having to give the specific color code each time. and allowing for ease of color changing #define red #define green #define blue or something along those lines Tag: Importing virtual functions from a Dll
  - 6
    - Methods/WebService called with regular intervals thanks guys for your prompt answers. I did think about using the sql server but the jobs that are beeing done are a bit complex and end by sending an email out. So I figure that's out of the question. Services I knew about and sound great and all, but as I'm not hosting my self and am not with a dedicated server I have limited access to the server and find it very unlikely that I will be allowed to set up a service in windows. are there no other means of doing this Tag: Importing virtual functions from a Dll
  - 7
    - how do you apply a class ok thank you. i have another problem though is the class I have created correct because the details are not being displayed when i run the app and click on one of the menu items. Tag: Importing virtual functions from a Dll
  - 8
    - Factory pattern problem Hi If you want the type specific properties also, then try having a GetProperties method on the base interface that returns a name value pair array. Each concrete type must implement this to return the set of properties [its own and the common]. Hope that helps. Regards Tag: Importing virtual functions from a Dll
  - 9
    - Boxing information required Hi Dave The object is set and the list has a count of over 0, did not add those for the purpose of the thread. 3) the holder will not be in the same memory place, but I was wondering about the reference it would be containing. From the previous reply I get it that the references would be the same. 4) Isn't boxing the action of putting objects inside structures or objects (If not gotta go check my def of boxing) Regards, Chryso Tag: Importing virtual functions from a Dll
  - 10
    - Best storage practices For relatively small amounts of data you can play around with serialized ADO.Net Datasets, this can give you basic SQL-like functionality with no cost. Other options are to look at something like MSDE (2000) One combination I've used before was to develop an SQL Server database using SQL Server Developer Edition (includes Enterprise Manager, Query Analyser, etc.) then deploying the scripts to an MSDE instance. If you don't need heavy concurrent data access then MSDE should be more than enough grunt. Tag: Importing virtual functions from a Dll
  - 11
    - Get the running instance of the program!! Hello, How to get the the current running instance of my application when i execute the application Like MSN Messenger, if i run one instance of it, then any trial to execute the program will activate the current instance!! I know some techniques to ristrict programs to run only 1 instance but how to get to this instance My program is used to watch created file, so it runs invisibly as the system starts to monitor the created files on my hard drives, now i want to allow users to activate the hidden instance when they press shortcut keys like CTRL+ALT+1 Thanks a lot Tag: Importing virtual functions from a Dll
  - 12
    - InvalidOperationException I changed the SetItemCallback to GetItemCallback however I do not understand how to do the steps you provided. Could you please show me the code for your steps Tag: Importing virtual functions from a Dll
  - 13
    - Algorithm for getting a value from a dynamic logarithmic scale? Wow, thanks a lot for dedicating so much time to my little problem! I didn't notice anyone had replied here, so I just used this function: public static double Scale( double value, double base1, double base2) { return ( Math . Log(value, base1) * Math . Pow(value, base2)) / 10D ; } And fed it with two "base" values I calculated beforehand in another application. However, this doesn't really work as I described, and your solution sounds very interesting!! Please do continue if you have the time, I would very much like to try out the resulting function! Is it possible to implement the maxvalue as described Thanks, //Sire Tag: Importing virtual functions from a Dll
  - 14
    - How to invoke a method defined by a derived class from the base class reference? Hi, Do you have some different implementation of ToLog in derived class Regards, Manju sandhu Tag: Importing virtual functions from a Dll
  - 15
    - Modifying an exception by ref? Thanks boban, that would work well, but in my case I don't want the caller of Retry to have to do special things with the exception. Inside OnException though, I can add a ref bool that indicates whether it is wrappering the exception. Then in retry I will be able to conditionally "throw;" or "throw ex;" where appreopriate. My version is not any more elegant, but I prefer to have the use of Retry be elegant, and the cludgy things be hidden away inside it. This is the final implementation: #region Retry generics /// <summary> /// A delegate that returns type T /// </summary> /// <typeparam name="T">The type to be returned.</typeparam> /// <returns></returns> public delegate T Func<T>(); /// <summary> /// An exception handler that returns false if Exception should be propogated /// or true if it should be ignored. /// </summary> /// <returns>A indicater of whether an exception should be ignored(true) or propogated(false).</returns> public delegate bool OnException(ref Exception ex, ref bool rethrow); /// <summary> /// Repeatedly executes retryThis until it executes successfully with /// an exception, maxTries is reached, or onException returns false. /// If retryThis is succesful, then its return value is returned by RetryUntil. /// </summary> /// <typeparam name="T">The type returned by retryThis, and subsequently returned by RetryUntil</typeparam> /// <param name="retryThis">The delegate to be called until success or until break condition.</param> /// <param name="onException">Exception handler that can be implemented to perform logging, /// notify user, and indicates whether retrying should continue. Return of true indicates /// ignore exception and continue execution, and false indicates break retrying and the /// exception will be propogated.</param> /// <param name="maxTries">Once retryThis has been called unsuccessfully <c>maxTries</c> times, then the exception is propagated. /// If maxTries is zero, then it will retry forever until success. /// </param> /// <returns>The value returned by retryThis on successful execution.</returns> public static T RetryUntil<T>(Func<T> retryThis, OnException onException, int maxTries) { //loop will run until either no exception occurs, or an exception is propogated(see catch block) int i = 0; while(true) { try { return retryThis(); } catch ( Exception ex ) { bool rethrow =false;//by default don't rethrow, just throw; to preserve stack trace if ( (i + 1) == maxTries ) {//if on last try, propogate exception throw; } else if (onException(ref ex, ref rethrow)) { if (maxTries != 0) {//if not infinite retries ++i; } continue;//ignore exception and continue } else { if (rethrow) { throw ex;//propogate exception } else {//else preserve stack trace throw; } } } } } /// <summary> /// Repeatedly executes retryThis until it executes successfully with /// an exception, or onException returns false. /// If retryThis is succesful, then its return value is returned by RetryUntil. /// This function will run infinitly until success or onException returns false. /// </summary> /// <typeparam name="T">The type returned by retryThis, and subsequently returned by RetryUntil</typeparam> /// <param name="retryThis">The delegate to be called until success or until break condition.</param> /// <param name="onException">Exception handler that can be implemented to perform logging, /// notify user, and indicates whether retrying should continue. Return of true indicates /// ignore exception and continue execution, and false indicates break retrying and the /// exception will be propogated.</param> /// <returns></returns> public static T RetryUntil<T>(Func<T> retryThis, OnException onException) { return RetryUntil<T>(retryThis, onException, 0); } #endregion Tag: Importing virtual functions from a Dll
  - 16
    - Order of properties, methods I personally put my privates after my publics (which I also used to do with my C++ classes). My rationale for this is that when a user is looking at my source code to see how to use the class, they will look at the public part. If the publics are near the top, they won't have to scroll past a load of private implementation details to find them. (I also use #regions to separate out the public/private bits, so if someone has got outlining turned on the order is less significant, of course.) Tag: Importing virtual functions from a Dll
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  - 1
    - Can't See the Toolbox I had something happen while programming C# in Visual Studio where all my windows (Solution Explorer, Class View, Output, etc.) undocked from the edges of the window, and many of them were turned off. I went on the View menu and got most of them back, but when I hit the button the View menu to show the Toolbox, nothing seems to happen. I've tried turning it on and off several times, and I tried restarting Visual Studio, but whatever I do I can't seem to find the Toolbox again. Can someone tell me how to make it visible again Tag: Importing virtual functions from a Dll
  - 2
    - I am such a beginner Thank you so much. It does make sense. Is there a way to list the properties of the sender and the parameters so that a beginner can see whats under the sheet, so to speak The other question I have is, if I have VS 2005, do I still need Expressions Web or Visual Web to create ASP.NET applications Tag: Importing virtual functions from a Dll
  - 3
    - Which One is faster???? Definitely quicker to do "if (str.Length == 0)" Tag: Importing virtual functions from a Dll
  - 4
    - Clearing class instance Navaneeth wrote: Thanks but, it's foolishness to do so. Because I can catch that exception where I am invoking the class and I can continue using the object. Throwing an exception won't make the class instance not usable. No you can't continue using the object, because you will not have a reference to it if the constructor throws, even if you cantch the exception. Tag: Importing virtual functions from a Dll
  - 5
    - Datetime problems... Hi, I am trying to set up a scheduling type of function in a web application using c#. Basically, the user picks a date on a calendar and then selects an option in a dropdownlist. The dropdownlist is populated like: 00:30 01:30 02:00 and so on.... I then take that data and insert it into a sql database as 1 column. I first tried parsing to strings etc but ran into a whole heap of problems. Now i'm simply truying: // Get the date and times selected dtSelected = Calendar1.SelectedDate; dtSelected = DateTime .Parse(DropDownList1.SelectedItem.Text); This seems to reset the date part back to its default. So for example, when the screen loads i tell the calendar to display today: // Initial page load events if (!IsPostBack) { // Set the calendar and label for currently selected date Calendar1.SelectedDate = DateTime .Today; Label1.Text = Calendar1.SelectedDate.ToShortDateString(); dtSelected = Calendar1.SelectedDate; } If the user selects another date, then the date doesnt change when submitted. What is the easiest way to do this Have a calendar, and a dropdown list of times. Then create a datetime type and assign a date to it, and then add just the time onto the end Thanks! Tag: Importing virtual functions from a Dll
  - 6
    - use of Debug folder's Database ????? Peter, then why there is difference to give connection to local copy database(.mdb) and debug copy database(.mdb). My real problem is : i have used DataBinding Method through DATASET DESIGNER (FROM MSDN LINK: ms-help://MS.MSDNQTR.v80.en/MS.MSDN.v80/MS.VisualStudio.v80.en/dv_raddata/html/12360f54-db6c-45d2-a91f-fee43214b555.htm) but update is not updating to local copy database so my toutor has suggest me do this step. And it is work . I want to know the real result behind that. 1. i have connect database(.mdb) through local copy . 2. then i have run it. so i have copy of Database in the Debug folder. 3. now i have modify the connection of Database to the Debug folder. 4. then set properties of Database: Copy to output Directory is set to Copy if newer plz tell me what is the real result behind that. peter i am waiting for you. Tag: Importing virtual functions from a Dll
  - 7
    - what is the difference between component and control Just to expand on Christian's post... A Control adds visual representation to Component, it's implementation being: public class Control : Component , System.Windows.Forms.ISupportOleDropSource, IDropTarget , ISynchronizeInvoke , IWin32Window , System.Windows.Forms.Layout.IArrangedElement, IBindableComponent , IComponent , IDisposable { } Andrej Tag: Importing virtual functions from a Dll
  - 8
    - where are WM_ messages I am coming over to C# from C++ and am overriding WndProc but get an error that says "the name WM_CHAR does not exist in the current context" is there a namespace that I need to include to have access to use this, or is it done entirely differently in C# Tag: Importing virtual functions from a Dll
  - 9
    - Performing 2-way encryption using the RijndaelManaged Class I have been tasked with creating a single-signon (SSO) functionality using a 2-way encryption hash. I found examples using RSA encryption, but is there a way of implementing a 2-way encryption hash using the RijndaelManaged Class Can someone point me to a good article or email me an example Thanks in advance. Tag: Importing virtual functions from a Dll
  - 10
    - Resources for Class Libraries Neutral language always goes with basic library. All additional satelite assemblies should be installed separatelly. Tag: Importing virtual functions from a Dll
  - 11
    - Converting from unsigned char* to Bitmap Hello all, I'm having trouble converting an unsigned char* into a Bitmap image. I have an unsigned char* in managed c++ code, which points to a 1280x1024 image with 8bppIndexed as the pixel format. When I display the image using the raw unsigned char* I'm getting the right image. In order to display the image on a C# console window, I need to convert the image from my C++ code in a System: rawing::Bitmap object. To do this, I have attempted to cast the pointer to IntPtr: IntPtr a_image_data = (IntPtr) const_cast < unsigned char *>( image_data ); //image_data is the unsigned char* I then used a delegate and event pair to send this IntPtr to the C# side of my project, and it retains the same IntPtr value. When I recreate the image using the IntPtr, it gives me an unrelated image. System.Drawing. Bitmap RetrievedImage = new System.Drawing. Bitmap (1280, 1024, 8, System.Drawing.Imaging. PixelFormat .Format8bppIndexed, ImageData); //ImageData is the IntPtr boxPic.Image = RetrievedImage ; //Display the image in PictureBox I think there is a problem in the casting. Please advise. Thank you. Tag: Importing virtual functions from a Dll
  - 12
    - I have a problem using class Directory My Directory.CreateDirectory(destinationDirectory) method do not create my directory on the disc ! has anioane any ideea why is it doing this Tag: Importing virtual functions from a Dll
  - 13
    - dynamic selection of connection strings Hi Taylor, I realised now this is the issue that I am facing now. I am trying to use configurationManager.ConnectionStrings but its picking up some default setting but not brining up my connection strings (defined in app.config). Do you have any example of this Thank you. Tag: Importing virtual functions from a Dll
  - 14
    - Accessing and Saving an XML File from a certain URL address. Hello, I am trying to code an application that will access an XML file in a certain URL(address). Then it will download the XML file and save it in the local machine of the user. 1. | user | -------- access ------->> | website | 2. | user | -------- gets ----------->> | file | //(in the website) 3. | application | ------- saves --->> | file | //(in local machine) for example, I have this URL ( http://phishtank.com/web/database/updates/index.xml < this is not an existing address, just an example) then I would like my application to access the XML file and or download the XML file into the user's local machine so that I can use its data in my application. Thanks. Tag: Importing virtual functions from a Dll
  - 15
    - Finalize and Dispose Sorry I don't think the issue was phrased right. I was wanting to ensure the Finalize was never being called and therefore my problem was that it was. However I have been through my tests 1 at a time and found out why (exception breaking out of method). Thanks for the interest shown Tom Tag: Importing virtual functions from a Dll
  - 16
    - MMC 3.0 Books/Resources? Anyone know any good books that teach MMC 3.0 development in C# I understand the basics, and can make simple snap-ins, but I wouldn't mind a book (or online resource) that really dives into it and shows the majority of the cool things that can be done (as opposed to me using trial-and-error to try to discover it). Thank you. Tag: Importing virtual functions from a Dll

Ventsislav Velev

I'm using VS2005 and I'm trying to import a bunch of unmanaged classes from a dll. The DllImport attribute, requires you to declare you methods as static extern, however that does not mix well with virtual functions.

I'm getting the following error: "Error 1 A static member CreateSignatureForSinglePackage(out byte[], int, out byte[])' cannot be marked as override, virtual, or abstract"

With pure virtual functions, instead of importing them from the Dll I declared them locally with an empty body, however if I use that same approach with "normal" virtual functions, I'll loose the code in the base version.

Any ideas

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Re: Importing virtual functions from a Dll

Peter Ritchie

You can only import functions that have a DLL entry point. You can't import C++ classes or C++ class members. When you use external functions they must be static which means they cannot be virtual.

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