I've heared people talking about these hashtables a lot but I don't know what are they for (what are they good for). From the System.Collections.Hashtable namespace I can see it's some kind of collection. Could anyone please fill me up on this ?
Hi Desmond. A hashtable is a collection object which contains items in key/value pairs. The keys function as indexes, and through them relatively fast searches are supported. Make sure you look at the examples in the .NET Framework documentation.
I am going to work in a project related with electronic signature. The project (which is not well defined yet) must be developed with the Microsoft .NET technology. Really i don´t know anything about .net technology, so my question is:
Is MS .Net technology "especially helpful" in the development of this kind of applications?
...and if is possible, Could you give me any link/article/book which talks about this issue?
a lot of thanks and sorry for my poor english.
My C# project Form is splitted into two parts,
the left side is a tree view,
the right side is a PictureBox.
I want to design a function,
When I click the menu button <new_page>,
A new PictureBox will appear,
like the MDI Form does.
How to new a PictureBox like that...??
or there are other better solutions...??
My original PictureBox's image must be saved,
so I can't just change it's image,
But if I want to new many pages,
New many PictureBoxes doesn't seem to a good way...??
Please give me a hand,thanks a lot!!
A quick side note:
if you only need the images to be saved during run-time (i.e. for GUI purposes) you can also
crate a list or array of System.Drawing.Image just to keep them in memory,
this could save you the usage of files, which you should afterwards clean up, might be easier.
I am trying to write programme code in Visual Studio.Net to make a btn return different values if clicked more than once.Eg the button I am trying to write code for would be similar to one found on a mobile phone, ie it can enter both numerical and alphabetical characters.
For example if the button contained the digit 2 as well as the letters abc, Clicking a button for the first time causes the first letter of the sequence to be added to a string (a). Rapid clicking should advance within the sequence ie, 2 clicks causes the second letter to be entered (b), 3 clicks causes the 3 letter (c). After reaching the end of the sequence, the sequence restarts (a). Selecting a letter from a sequence must be completed within 1 second otherwise the sequence restarts(a).
What I cannot work out is the code required to measure the time in between clicks and the function description to indicate a button has been clicked more than once or multiple times.
For the time monitoring you should use the System.Timers.Timer Class.
create a timer object System.Timers.Timer BtnTimer
and set the interval to 1000 (1 second)
use something like flag (BOOL blDuringClick;) that will determine whether you are during a 'rapid' click time, on the button's click event set blDuringClick = True and use BtnTimer.stop and then BtnTimer.Start(so each click resets the timer), and on the Elapsed event for the timer set blDuringClick = False
now when you handle click events check if you are during the rapid click by checking blDuringClick's value.
For checking the character,
there are many ways to do it, maybe the easiest one is to have a string for each button holding something like "2ABCabc" and then cycle through the chars (hold an index, and remember to check bounds).
today i installed VS.Net and after that i downloaded some code samples from microsof's site, and when i try to open the sample project, a message comes and says, "Your project file version is '7.10'. Visual Studio .NET can only load version 7.0 project files".
how can i get the higher version ...? is it available like a patch/update..????
Use System.IntPtr. Use IntPtr.Zero where you would pass a NULL.
A common pattern is to wrap the HANDLE with a simple wrapper class that implements the IDisposable interface and has a finalizer (the ~ClassName function in C#, or an override of Finalize in VB.NET) which calls Dispose. Inside your override of Dispose you should suppress the finalizer using GC.SuppressFinalize (this allows the object's memory to be freed earlier if Dispose is called explicitly) then call whatever function frees the HANDLE.
I am building an application that will use Microsoft's ODBC .NET Data Provider. That is an extension that is not installed by default with the .NET framework. I would like my application to detect whether the data provider has been installed on the machine where it is running during startup.
You cannot do it using that technique. Probably, the only way to do it is using a 3rd party component. Try Aspose.com. I have not tried their Excel component, but their PDF one worked very well - we stream the PDF directly to the browser, no temp file.
I read from a Microsoft guide on Performance (www.serverside.net) and it says that Windows Services uses Workstaton GC even Server has multiple CPU. The conclusion seems to be that we should not host TCP Remoting in WinSvcs.
(1) Is the above true or false ? (I have seen various opinion on this)
(2) How to configure to use Server GC (
I have some idea but not sure about it. But I will open source it so everyone can comment later.
If the .NET Framework is implicitly loaded, by loading a managed executable or loading a library into a process where the Framework isn't already loaded, the Workstation GC will always be used. To use the Server GC, you must explicitly load the framework by calling CorBindToRuntimeEx, exported by mscoree.dll.
Thanks for your "real-time" response.
I have read both articles: The 1st is great in concept and the 2nd has
My Company blocked Blogging so I have to wait till after 6pm at home to read.
I basically modified Steven Pratschner's code and made a Windows Services (.net) that calls Unmanaged API CorBindToRuntimeEx to run a remoting host code. (Just like you said). It really works as a TCP Remoting Host.
Though My problem is that I would rather not use my code since it does not have PROVEN scalability in production.(and I do not have 8-CPU machine anyway)
Is there any code I can download that has been proven ?
PS. I have no problem upload my code onto www.codeproject.com, so that we developer can improve and test it in this community.
I am using a commercial protocol stack that calls a registered callback function to receive data when the driver it talks to has done it's thing and has new data to report. The sample code that came with the stack uses PostMessage from the Win32 world to send a local copy of the data back to the host GUI/window message parsing thread. This is to avoid thread crossing problems, etc.
I want to do the same thing with a new .NET application. But, I can't see a way to do it. I can't spawn a new thread, call invoke, etc. because I have to follow the signature of the callback function. I can't just add the callback function into my form namespace for the same reason. I can't call PostMessage because .NET hides the message pump parsing and I don't know how to add handling a custom message, assuming I could succesfully send it. IMessage doesn't see to apply... It seems like this would be an easy question.
I'm developing a setup project. Can you help me with these queries
- How do I get the installation path the user enters at runtime
- How can I copy some files to specified location eg:C:\temp
- How can I check for existence of a particular folder? Is it possible with Launch Condition. If not how can I do it?
-'User Interface -Add Dialog '- How can I get the values entered in the textboxes at runtime and pass it to my application?
- Custom Action properties , properties- Installer Class - true / false signify ?
- How do I start an application when Installation completes ?
Thankx in advance