C#

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problem retrieving values from combo box Rashid_Mehmood6-Dec-04 20:06 Rashid_Mehmood 6-Dec-04 20:06  Dear Members I have two questions, plz guide and oblidge 1). I populated the combo box by binding it with a dataset containing record of a user(i.e registrationNumber and userName). I set userName as the DisplayMember of combo box. But when I tried to get the value of selected user by writing objCombo.SelectedItem.ToString() or objCombo.SelectedValue.ToString() or objCombo.SelectedText it returns me an object of DataRowView type and not the selected value. Plz guide how can I get the selected value? Plz also guide that is it possible that on selection of registrationNumber, I could get the userName against it? 2). How can I perform only the time manipulation through datetime object? Regards Re: problem retrieving values from combo box sreejith ss nair6-Dec-04 21:24 sreejith ss nair 6-Dec-04 21:24  You can use Combo1.Text property to get the latest selected value from the list. And suppose if you want to get the username after selecting the registration number, then you have write some logic to get it. And what you really mean by time manipulation ? Will you explain it little bit more ? Sreejith Nair [ My Articles ] Re: problem retrieving values from combo box Skynyrd6-Dec-04 23:05 Skynyrd 6-Dec-04 23:05  U are trying to get the selectedvalue of your combo while ur datasource is filling up. Change ur event handler to SelectionChangeComitted (only fires when user changes the cbo, not code induced changes, as when filling up the datatable ur are linking to). If ur source table has the userName and the registration Number, then simply bind the displaymember to the username column and the valuemember to the registrationNumber column. Get the selected item info through Text and SelectedValue. Get data type and Create table Member 10976996-Dec-04 19:37 Member 1097699 6-Dec-04 19:37  Hi, I'm working on C# with foxpro database and I want to get type of field in a table of Foxpro database from C#. I also want to create a table in Foxpro database from C#. Would you tell me How to do it? Thanks for your help. Regard, Embedding Win32 dll Yaakov Davis6-Dec-04 18:43 Yaakov Davis 6-Dec-04 18:43  It is posible to embed a Win32 dll into .Net dll? Re: Embedding Win32 dll Daniel Turini6-Dec-04 20:11 Daniel Turini 6-Dec-04 20:11  No, but you can call it using P/Invoke (search for DllImport). Yes, even I am blogging now! Re: Embedding Win32 dll sreejith ss nair6-Dec-04 21:36 sreejith ss nair 6-Dec-04 21:36  Yes. You can use Win32 dll's in your .NET dll. The idea P/Invoke is there to help you out. Please refer this link Interoperability Sreejith Nair [ My Articles ] Re: Embedding Win32 dll Yaakov Davis7-Dec-04 1:35 Yaakov Davis 7-Dec-04 1:35  I'm afraid my question was misunderstood. I did use the P/Invoke (and C++ Interop as well) to call some functions in Win32 dll, but when I want to run the program on different computer, I need to copy the dlls I called, to the same directory Where the .Exe resists. There is any way do embed the dlls into the .exe? My problem is security. I'm afarid that somebody will replace the dlls with his own. Strong name isn't an option here, since the dlls are Win32 ones. Thanks, Yaakov Re: Embedding Win32 dll sreejith ss nair7-Dec-04 1:53 sreejith ss nair 7-Dec-04 1:53  You Wrote :when I want to run the program on different computer, I need to copy the dlls I called, to the same directory Where the .Exe resists. No. Each and every Windows operating system contain this Win32.dll file (excluding Windows 95. I think here it is Win16.dll) in it's System32 directory. So you don't want to copy the calling .dll. Refer using DllImport Attribute. Hope you understood.Please see that url that i attached in my last thread. Sreejith Nair [ My Articles ] Re: Embedding Win32 dll Yaakov Davis7-Dec-04 2:06 Yaakov Davis 7-Dec-04 2:06  sreejith ss nair wrote: So you don't want to copy the calling .dll. Hi. I DO want to copy the dll, since it isn't a windows dll. it's a dll of some third party API. The program doesn't load without the dll in the running directory. I'll repeat my problem to make it clear. I use an external Win32 (i.e. not .Net) dll which contains function foo(). The dll isn't part of Windows. I'm afraid that somebody will place in the folder a dll with the same name, that contains some malicious function foo(), who do some evil job before he calls in turn to the original foo(). I thought I can avoid this, if I find a way to embed the called dll in my application. I'm open to another suggestion or information. Thanks for your help. Anybody please? Yaakov Davis7-Dec-04 3:46 Yaakov Davis 7-Dec-04 3:46  Yaakov Re: Embedding Win32 dll Dave Kreskowiak7-Dec-04 4:32 Dave Kreskowiak 7-Dec-04 4:32  There is no way to do this. Even if you packaged the .DLL into a resource in your .EXE, you'd still have to unpack it, save the .DLL file to the folder where your app is installed, and then call it. But, someone that malicious could also just put a replacement .DLL into the folder where your app is installed, either tag it ReadOnly, or some other methdo to keep your app from putting the .DLL down successfully, whatever, and then your app would still call the bad .DLL. The only method you can use to validate the .DLL is to run some kind of checksum, or some other file validation, on the .DLL file before you call it. But this is no way guarantees that the file your looking at is legitimate and it will also keep your application tied to a specific version of the .DLL file. But this is a calculated risk that EVERY Windows application takes. There is just no reliable way to do this with a Win32 .DLL. Every Win32 .DLL can be impostered by a custom written replacement, using the same signatures and GUID's as your .DLL. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome Re: Embedding Win32 dll Yaakov Davis7-Dec-04 8:10 Yaakov Davis 7-Dec-04 8:10  Dave Kreskowiak wrote: ...the same signatures and GUID's as your .DLL. Thanks for making things clear. How can I get the GUID and the signature? Yaakov Re: Embedding Win32 dll Dave Kreskowiak7-Dec-04 11:42 Dave Kreskowiak 7-Dec-04 11:42  The GUIDs are scattered abou in the registry. You'll need to search for the object names exposed by the .DLL in order to find them. The function signatures cannot be had unless you have the source code for the .DLL. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome Another question Yaakov Davis7-Dec-04 11:54 Yaakov Davis 7-Dec-04 11:54  Thanks for your answer. And here is another one which related to the previous. I looked for the Al.exe documentation in the MSDN, and it explains the /link argument: /link[resource]:file[,name[,target[,private]]] Links a resource file to an assembly. The resource specified by file becomes part of the assembly; the file is not copied. The file parameter can be in any file format. For example, you can specify a native DLL as the file parameter. This will make the native DLL part of the assembly so that it can be installed into the global assembly cache and accessed from managed code in the assembly. Isn't that what I was looking for? However, I tried this, and I get the message: /link:... option not recognized. Yaakov Re: Another question Dave Kreskowiak8-Dec-04 1:53 Dave Kreskowiak 8-Dec-04 1:53  Interesting. But I have no clue how you're going to access the .DLL inside the assembly. Also, if your .DLL is a COM component and must be registered, I have no idea how you're going to get that accomplished while it's sitting inside a .NET assembly. It's just never been a requirement for me. If someone is going to do something malicious with my code, they're going to succeed weather I want them to or not. It's just up to that persons determination. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome Custom Web Component Problem Jacob Koppang6-Dec-04 16:33 Jacob Koppang 6-Dec-04 16:33  I'm writing a custom web component with a custom collection class. Today, I sat down to work, dragged a copy of the component from my toolbox onto a webform and discovered the error, "Parser Error: Ambiguous match found". I found a KB(http://support.microsoft.com/?kbid=823194[^]) article on it, but it didn't help at all. The compiler just says "<namespace> does not contain a definition for 'ObjectString'. I'm scoured the internet, but no to avail. If you could help, it would be much appreciated. Register dll files johnie836-Dec-04 14:24 johnie83 6-Dec-04 14:24  Hi guys, I am making windows application using C# which used a number of dll library files. But, it cannot run in every computer, it says that "the class is not registered" or something like that. I'm also tried to use GACUTIL.EXE / i [dll file] But it give me another error message : "Failure adding assembly to the cache: Attempt to install an assembly without a strong name" It give me the same result when I use regsvr32. Is anyone know how to solve it? Thanks be4 Re: Register dll files sreejith ss nair6-Dec-04 21:32 sreejith ss nair 6-Dec-04 21:32  You wrote I am making windows application using C# which used a number of dll library files. But, it cannot run in every computer, it says that "the class is not registered" or something like that. Here i am little confused. Reason is the matter of registeration. Tell me how you are refering those assemblies in your application. ? You wrote "Failure adding assembly to the cache: Attempt to install an assembly without a strong name" This error is cause, there is no strong name in your assembly which you are trying to install into GAC. What you can do is, use sn.exe tool to create a .snk file( Strong Name Key File). And refer this file name and location in your actuall assembly which you are trying to install into GAC. Sreejith Nair [ My Articles ] Re: Register dll files johnie837-Dec-04 0:22 johnie83 7-Dec-04 0:22  It works!!! Thank you very much How to extract default page margin of a printer? sachinkalse6-Dec-04 14:23 sachinkalse 6-Dec-04 14:23  If I set page up/down/left/right margins to 0, some part of the page doesn't get printed. It seems printer has got certail default minimum page margin settings, that decides printable area on given paper, can we read them using WMI or by any other means? Please guide. Calculating ticks per second Tristan Rhodes6-Dec-04 10:33 Tristan Rhodes 6-Dec-04 10:33  Hi, I've found the Enviroment.TickCount property, but i'm baffled as to how to use it to calculate cycles per second. I'm trying to optimise a number of sections of code, and i understand taking the final TickCount minus the initial TickCount, but i'm not sure how many ticks per second my CPU does so I can't really get a real world value for this. Any ideas? Is there any way to calculate this? Cheers Tris Re: Calculating ticks per second leppie6-Dec-04 10:48 leppie 6-Dec-04 10:48  The Catalyst wrote: Is there any way to calculate this? No, it is defined in the windows header files, if memory serves me correct its 10 000. top secret Download xacc-ide 0.0.3 now! See some screenshots Re: Calculating ticks per second Tristan Rhodes6-Dec-04 11:01 Tristan Rhodes 6-Dec-04 11:01  But, one Tick is a single Clock Cycle on the CPU. So it can't be fixed. You're running a 10khz cpu? I mean, it's obvious if you know the clock frequency of the CPU, but there has to be some way to figure it out, without doing int start = Enviroment.TickCount; Thread.Sleep(TimeSpan.FromSeconds(1)); int finish = Enviroment.TickCount; MessageBox.Show("Ticks Per Second: " + (finish - start).ToString()); Cheers Cata Re: Calculating ticks per second Dave Kreskowiak7-Dec-04 4:15 Dave Kreskowiak 7-Dec-04 4:15  The Catalyst wrote: But, one Tick is a single Clock Cycle on the CPU No, it's not. One Tick, defined in the .NET Framework, is 100 nanoseconds, see this[^] for the definition. There is no counter anywhere in the .NET BCL that counts the number of CPU clock cycles that have elapsed. Also, TickCount does not have a high enough resolution to perform the measurement you want. It's accuracy is limited to 500 milliseconds at best. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

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