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I have a class library I wrote, which deals with sockets.
I raise events through this library, such as DataArrival (which gives me the problem btw).
This is a snippet from my receiveCallback function:
Buffer bf = (Buffer)result.AsyncState;
bf.QueuePacks();
if (OnDataArrival != null)
{
if (caller != null) caller.Invoke(OnDataArrival, bf);
else OnDataArrival(bf);
}
sck.BeginReceive(bf.Data, 0, bf.Data.Length, SocketFlags.None, new AsyncCallback(receiveCallBack), bf);Buffer is also a class I wrote, and caller is a reference to a form.
This code works most of the time.
I'm currently working on a new project which uses my class.
In this project, I sometimes get an "Parameter is invalid" exception, on this line:
caller.Invoke(OnDataArrival, bf); It works most of the time, and never happend in my previous projects.
Is it wrong to invoke an event?
What's wrong with my parameters?
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shyagam wrote: Is it wrong to invoke an event?
What's wrong with my parameters?
Care to provide some more details?
As of how to accomplish this, have you ever tried Google?
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Ed.Poore wrote: Care to provide some more details?
Well... I don't really know what details I can give you...
Could you please point me in the right direction?
Ed.Poore wrote: As of how to accomplish this, have you ever tried Google?
Of course! That's how I knew I should use the Invoke method... 
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I meant details as to the exception, stack trace etc.
Nader's advice holds strong though.
As of how to accomplish this, have you ever tried Google?
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Hello
shyagam wrote: I sometimes get an "Parameter is invalid" exception
You said "Sometimes", while other times not!! try debugging each call-;P- to Invoke, and see the values of the parameters, what's wrong with them. Also try to understand the pattern of the exception. Maybe a certain call is the problem. When the code works sometimes, it should work all the tims. So another code could be causing the problem.
shyagam wrote: never happend in my previous projects.
I guess this should point you to the possibility that the problem is in the current project!!
Regards
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I have inserted a DataGridViewCheckBoxColumn in a DataGridView. But whenever I click on its DataGridViewCheckBoxCell, the box is not checked. How do I check it? Is any event needed?
dgvcbc = new System.Windows.Forms.DataGridViewCheckBoxColumn();
dgvcbc.HeaderText = "Check to delete";
dgvcbc.Name = "Check to delete";
dgvcbc.CellTemplate = new DataGridViewCheckBoxCell();
dataGridView1.Columns.Insert(0, dgvcbc);
Thanks!
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Hello
The problem is for sure NOT in the code that you've posted. Are other columns in the DataGridView working too?!! Maybe you've set the eable to false by mistake or something. The above code should work fine!!
Regards![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
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Hi,
There is only one DataGridViewCheckBoxColumn in the DataGridView. Other columns are mainly DataGridViewColumn and DataGridViewLinkColumn. The links work perfectly.
You mentioned the setting problem. What do you think has been set to false by mistake? What is the code for that setting?
Thanks again.
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Hello
Well, as I told you in my previous post, this code should work!! You can tamper with the settings of your DataGridView in a way that it may stop responding. I gave you an example. Check the Enable
Also check to see if you've made this column as ReadOnly. You can check both from the property grid.
When I asked about other columns, I meant are they working in any how?? Can you edit the cells??
Regards
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Hi,
Do you mean the dataGridView.Enabled property? But it is set to true which allows user interaction. And the CheckBoxColumn isn't set to ReadOnly. So what else should I check?
Thanks!
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Hello
Well, err... Yes! Forgive the typo. I mean Enabled.. I'm running out of guesses here. Try to add another CheckboxColumn, and see what happens. Also you didn't answer my question. Do other Text columns work? Can you type in them?
Regards ![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
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Hi,
It's working now. I found out that the datagridview is readonly though I checked that the checkboxcolumn is not readonly.
Anyways, thanks very much for your help.
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I need to know how to edit a combobox on a web page in a webBrowser object (using MSHTML). The code for the combobox in HTML uses the SELECT and OPTION tags. I can check the checkboxes, fill the textfields and click the buttons, but I can't figure this one out. Any help would be appreciated! Thanks!
Scott Clayton (My birthday was on the 23rd!)
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Hi Everybody! 
Can anyone recommand program that creates and HTML in MSDN style out of the xml documentation?
I've been looking for one on the web, but strangly I couldn't find one! (I thought there would be dozens!)
Thanks!
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Hello
Green Fuze wrote: Can anyone recommand program that creates and HTML in MSDN style out of the xml documentation?
Sounds very much like a tailored program. And what do you mean by MSDN style exactly?!!
Also what Xml input will you give it to the program?
Regards
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Nader Elshehabi wrote: And what do you mean by MSDN style exactly?!!
I would imagine he means that it functions like MSDN
Nader Elshehabi wrote: Also what Xml input will you give it to the program?
The XML that Visual Studio creates if you complile the assembly with the Produce XML Documentation project setting turned on.
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I'm looking for something like JavaDoc in java.
Lets say you wrote a new class and you used the XML to write the API (or interface) of your class - all the public members of the class, and what do they do (so user will be able to use your class with ease).
in Java has JavaDoc.exe file that generate an HTML containing all that information from the source file itself.
since c# get only output XML I guess that there is a program that transforms the XML into an HTML (so it will, eventually, do the same as JavaDoc).
And by writing MSDN style, I meant HTML that looks like the MSDN APIs on the MSDN website.
hope it makes things a bit clearer
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Green Fuze wrote: Can anyone recommand program that creates and HTML in MSDN style out of the xml documentation?
NDoc[^]
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Thanks!!!
I'll check it out!
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I was wondering how long it would take someone to point this out. 
As of how to accomplish this, have you ever tried Google?
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Hi
Does anyone know how do i can open a network printer as a file in C#?
I am using a xerox printer and would like to be able to send 'VIPP' comands
to it easily once i have written a reusable class that will facilitate this.
I can open the printer and write a line to it in vb6 just like this:
Open FindPrinter("\\ip123\thePrinter") For Output As #1
Print #1, "%%XGF example print command" //this would be a special print command
Close #1
the equivalent in C# as far as i can see does not seem to work:
IO.StreamWriter swMyPrinter;
swMyPrinter = new IO.StreamWriter("\\\\ip123\\thePrinter");
swMyPrinter.WriteLine("Hallo\n");
swMyPrinter.Close();
this returns an error telling me i need to call 'CreateFile' myself and then
use 'FileStream' contructors if i want to open devices like this. I think
this type of thing may only allow me to open a local printer on LPT1 as it does
not seem to be able to open the handle to the printer.
Is there a simple way of opening a network printer for writing?
Thanks in advance
Edd
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Hello
In C# you can't access ports -and other devices as well- directly using FileStream. I don't know why they didn't add this support though!! If you do it throws System.NotSupportedException with this message:
"FileStream was asked to open a device that was not a file. For support for devices like 'com1:' or 'lpt1:', call CreateFile, then use the FileStream constructors that take an OS handle as an IntPtr."
Now just like the message said, to access divice in C# as files do the following:
1- Use P/Invoke to call Win32 API function called CreateFile with the name of the device -in your case it will be @"\\Computername\Printer Share Name"
2- Retreive the handle to the device from the above function
3- Give that handle to one of the FileStream constructors overlosds that takes Argument 1 as a IntPtr
4- Now you have a FileStream object and you can access the device as a file
Regards
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thanks for the quick reply
thats exactly the error message i got, after a bit of research I found a small tutorial on how to do this but didnt manage to successfully get it to work. I could well have done somehing completely wrong though (ive ben using c# for about 2 weeks so far so alot of this is quite daunting).
I shall endevour to give this another go when i get back to work.
thanks again
edd
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Edd,
Is the tutorial you found online? I too need to access a printer with C# and am very new to C#.
Thanks,
Carol
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