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Why does C# NOT support default parameters when VB.NET and C++ do?
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Because MS has decided they were a bad idea. Instead you should write overloaded method calls with the minimum params, all of them, and any intermediate combination that you feel is neccesary.
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I have a form which i use to initiate my windows application in Application.Run()
and i need a way to access a function within that form.
I need to do this because i have another active form which has to update the form created in the Application.Run(), and ive managed to show/hide the main form but not to access its functions.
// Example. In form B which has its owner set to the main form
ActiveForm.Owner.Visible = false;
This affects the main form but i cant seem to find where the public functions are or to edit anything beyond basic frame parameters.
Does anyone know how i can do this?
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You have to cast the return value of ActiveForm.Owner to the specific type.
if (ActiveForm.Owner is MainForm)
((MainForm) ActiveForm.Owner).Function(..);
www.troschuetz.de
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I tried your way before and i also tried (ActiveForm.Owner as MainForm).function
but neither of them gives me access to functions.. why?
It seems like the form created in Application.Run() have much more privacy and restrictions to it than other forms created.
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Which access modifier has the function? Did you declare it public or internal?
www.troschuetz.de
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the function is public and the form class is declared like this:
public class MainForm : System.Windows.Forms.Form
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I'm a bit at a loss than, cause in this case the given code should work.
What compiler error do you get for your code snippet (ActiveForm.Owner as MainForm).Function()??
www.troschuetz.de
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I am writing a windows service which will manage image capturing devices, when client connects to the service, at some point the service need to expose a device dialog to the client. According to MSDN docs, classes within the Windows Forms namespace are not supported for use within a Windows service. So How can I do that?
Thanks!
Hang
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You can't. You cannot send a dialog reference from a web service. You're going to have to capture the image from your insert device here using some other method. That method depends on your device. Then serialize and send the image it captured. You can't send a dialog like that.
In short, Web Services deal strictly with data. They cannot provide any kind of user interface to a client what-so-ever.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
-- modified at 12:49 Thursday 8th September, 2005
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I have an array of objects of a class having 10 fields. The first 5 fields should behave like composite keys of a sql table. So only objects conforming to the constraint can be added.
I dont want to use it.
I just need a simple logic to implement this in an ArrayList.
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Hi,
I have a very strange problem which i hope someone can help shed light on.
I have a Windows Forms application which provides data-entry UI. Data
inputted is then stored into a DataSet which will be persisted into a XML
file using the WriteXML method.
The Dataset which contains a Filename data column (type = string); A user
selects a file using the OpenFileDialog component. The file name is
displayed in a textbox until the user clicks on the Save button.
PROBLEM:
If the file is selected using the OpenFileDialog.ShowDialog() method, the
file name is added to the dataset, but it is not written to the XML file.
However, if the filename is manually typed into the textbox, saving to XML
file succeeds.
This is a very strange problem, any help will be very much appreciated!
Thanks.
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I can guarantee that the problem is in your code and not the OpenFileDialog. It looks liek you're putting the filename into the TextBox, but your not updating the dataset with the new name.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hi,
I'm trying to read the input of my IR Controller by raw input. I managed to get lParam (pointer) and some other variables out of it, and now I want to extract it to useable data.
I'm now able to make a difference between WM_INPUT of some other type, but there are like 10 keys on the remote using WM_INPUT. lParam seems the only parameter containing the info I need...
Thanks in advance.
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It sounds like you'll need to use some of the P/Invoke techniques. Look in the System.Runtime.InteropServices.Marshal class for some methods that you might need for handling the memory. Also, you will probably need to create a struct (marked with StructLayout(LayoutKind.Sequential)) that exactly matches the structure which your lParam is pointing to.
Read up on the P/Invoke stuff (Platform Invoke), and you'll probably fill in the important gaps in your understanding.
John
"You said a whole sentence with no words in it, and I understood you!" -- my wife as she cries about slowly becoming a geek.
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MSDN is your best friend in this case. According to MSDN, lparam is a "Handle to the RAWINPUT structure that contains the raw input from the device". Dig deeper here is the article on the structure: MSDN: RAWINPUT structure[^]
Alex Korchemniy
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Found a nice sample code: http://blogs.simplifi.com/brucet/downloads/remotecontrolsample.zip
It may help some others as well.
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Hi,
I have a System.Drawing.Bitmap of a screen capture that I want to convert to a byte array. Any ideas on how to do this? I expected the bitmap object to have some sort of ToArray method, but it hasn't.
I'm rather stumped.
TIA
Dr Herbie
Remember, half the people out there have below average IQs.
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You can save the image to a System.IO.MemoryStream, which does have the elusive ToArray method.
Charlie
if(!curlies){ return; }
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This should do the trick 
public static byte[] GenerateImageBytes(Bitmap bm)
{
byte[] bytes = null;
System.IO.MemoryStream ms = new System.IO.MemoryStream();
bm.Save(ms, ImageFormat.Gif);
bytes = ms.ToArray();
ms.Close();
return bytes;
}
Thomas
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Or, with slightly more pleasant syntax, with better resource management:
public static byte[] GenerateImageBytes(Bitmap bm)
{
using(MemoryStream ms = new MemoryStream())
{
bm.Save(ms, ImageFormat.Gif);
return ms.ToArray();
}
}
Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Cops & Robbers
Judah Himango
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Yes, this looks greate
But, will the MemoryStream be closed (ms.Close())?
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That's what the using statement is for. The using clause automatically disposes of any IDisposable objects, including MemoryStream, thus it will call the appropriate close method when the scope leaves the using clause.
Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Cops & Robbers
Judah Himango
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Hi folks!
I'm being bugged by a very nasty problem and don't know how to proceed any further, perhaps someone can enlighten me.
In my programs I need an RSACryptoServiceProvider to encrypt and decrypt stuff. In order to check whether this is possible during startup, I simply try instantiating the CSP. If this blows, the user is told to install the latest service packs, IE5.5+ or anything that usually includes the strong encryption CSPs.
The code to do this is
CspParameters param = new CspParameters();
param.Flags = CspProviderFlags.UseMachineKeyStore;
RSACryptoServiceProvider csp = new RSACryptoServiceProvider(param); so I'm already using the Machine Key Store.
This throws an exception (CryptographicException: CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired), if the application was installed by an administrator on a Win2K SP4 machine and is then run by a user with restricted rights (belonging to group "Users").
When the admin is running the application, the code above executes flawlessly AND afterwards, the restricted user also can run the program!
I've been searching for this problem for quite some time and only found reports where this exception is thrown in an ASP.NET context, but my applications are Windows Forms applications, not ASP.NET ones.
I can't find which additional rights the user has to have for the code to work before the administrator has at least run it once.
Giving full access to C:\documents and settings\all users\application data\microsoft\crypto\* didn't help.
I'm completely at a loss on what to do next.
Can anyone help?
TIA,
mav
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You may try to set the RSACryptoServiceProvider.UseMachineKeyStore Property to false so that the key could be persisted in the user profile store instead of the computer's key store. Try if it can work while not defeating the purpose of your application.
Regards,
Ashok Dhamija
_____________________________
Padam Technologies
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