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You can use the GetPrinter API call getting a PRINTER_INFO_2[^] structure and the cJobs property is the count of jobs in the queue.
The EnumJobs [^]API will give you details of each print job in the queue.
The PrintQueueWatch component source code[^] has these and many more printer related API declarations in it...
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Ahh great, that's given me a load to work with - cheers!
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When I run my VB.net WindowsApplication
I can see that (in the Process tab of Windows Task manager) the mem usage keeps on increasing.
Can someone tell me how to stop this or if we can retain the memory that was used up and no longer needed by the application.
Ashfaq Maniar, Software Developer.
Ashfaq Maniar, Software Developer.
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Erhm, there's this 'thing' called the Garbage Collector, this will clean up objects which are no longer in use. If thise 'collected' objects use loads of memory, that memory will be freed, and is available again. The garbage collector is very sophisticated and i'm pretty much sure it works fine for most applications. However, as programmer, you need to 'tell' the garbage collector which objects aren't used anymore. This way you will 'help' the garbage collector finding objects to free from memory.
All objects derived from the IDisposable interface, have this method called Dispose(). Dispose() will clean up all resources the object uses. If you're done using an object, call the Dispose() method so the garbage collector can do it's work. In C# the using statement helps you to not forget to call the dispose method. The example below instantiates a new object, but because i'm doing this with the using statement, the object will automatically dispose at the last bracket
<br />
using (ObjectType myObject = new ObjectType())<br />
{<br />
myObject.DoSomething();<br />
}<br />
This code is by the way the same as :
<br />
ObjectType myObject = new ObjectType();<br />
myObject.DoSomething();<br />
myObject.Dispose();<br />
You also need to find out which of your own classes are suitable to implement the IDisposable interface to they can also dispose themselves.
The garbage collector runs pretty much automaticly and you shouldn't interfere, however if you really feel like freeing memory is useful at a certain point, you can call the garbage collectors Collect() method :
<br />
GC.Collect();<br />
The collect however is pretty time-consuming and neat programmers don't need to use the Collect(). There may be exceptions to that however...
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I am using VB.net
When ever a class is not usable i type
class1 = nothing
But the main problem is .... when a form is open and when you click anywhere on the form...the consumed memory still goes up and comes down only when the user closes the application.
Ashfaq Maniar, Software Developer.
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On one of the machines I use, I have the VB Express installed.
(I know, I know...it was quick and nasty and used for the odd small thing)
I tried to do something that wrote to an XL sheet.
Is it me or does VB Express not support writing directly to XL?
Am I not declaring properly in a reduced syntax environment perhaps?
Am I being incredibly dim and missing something rather fundamental?
Please clarify and enlighten, my ignorance is annoying me!
------------------------------------
"I want you to imagine I have a blaster in my hand" - Zaphod Beeblebrox.
"You DO have a blaster in your hand" - Freighter Pilot
"Yeah, so you don't have to tax your imagination too hard" - Zaphod Beeblebrox
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Hi ,
I need a Single DES or Triple Des or AES code in Dot Net...
Regards,
Narayanan.S
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I googled and found tons of code.
Christian Graus
No longer a Microsoft MVP, but still happy to answer your questions.
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in which version you want this code.
VS 2005 and later has directly support for any type of encryption algorithm like AES, DES, RSA etc.
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Thanks For ur Reply...
I have seen that code , but i could`t undestand the logic behind that Algorithms ... I got lot of documents Regarding that algorithm, but
I could`t undersatnd how they r using the keys for Encryption & decryption and all....
Regards,
Narayanan.S
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Please let me know .. if you want the sample code for the same ...
and regarding which type of encryption algorithm
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Hi, I need help connecting an access file with my project I am working on in Visual Studio 2008 (I also have Visual Studio 2005).
I know how to connect to SQL databases but access is totally new to me. My friend told me that just add it through the "Add data source wizard" and then drag the columns you need from the "Data Sources" side bar.
I did that the connection was established and I the navigation bar was also created automatically, when I ran the program, it was showing the records from my access file, I was able to add or delete records but the changes I made to the database are just temporary and are not saved in the database (THIS IS WHERE I NEED HELP)
Please answer this question, I am stuck because of this problem, and please answer it as descriptively as possible because I am new to coding and don't know much.
I don't know ADODB or anything else like that but am willing to try anything just want to be able to access, edit and update any access file from within my program.
Thanks for your help in advance.
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I thought you just create a connection string with the path to your access file ?
Christian Graus
No longer a Microsoft MVP, but still happy to answer your questions.
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Could you please give me a sample program or tell me where I can get one which would be able to retrieve, change, delete and add records in an access database.
I would be very grateful if you would assist me in this matter.
Thanks for your any help in advance.
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Use the following connection string using the OleDb dataadapter to make the connection
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\DOT_NET\DB\db1.mdb;Persist Security Info=False
and after update the data please close the conenction and release the created object.
Please let me know if u want sample code for the same.
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Good Morning Muhammad Zaid Pirwani
The Problem when using the Wizard is that you will never understand what is wrong when something is wrong. i suggest you start writting code and connect to your Database your self. its simple. You are going to do the Following
In your Project as you know you have to import the Following
Imports System.Data
Imports System.Data.OleDb
And your code for Database Access , should be Something like this
'Connection String for the Access Database
Dim strCon As String = "Data Source=C:\Valuation Roll\ValuationRoll_CD.mdb; Provider=Microsoft.Jet.OLEDB.4.0;persist security info=False;User ID=Admin"
Dim con As new OleDbConnection(strCon) 'Declaring a Connection Object
Dim cmdselect As new OleDbCommand 'Declaring a Command object
Dim da As new OleDbDataAdapter 'Declaring an Adapter
Dim dsdata As New DataSet
cmdselect.CommandText = "SELECT * FROM mytable"
cmdselect.CommandTimeout = 0
cmdselect.CommandType = CommandType.Text
cmdselect.Connection = con
da.SelectCommand = cmdselect
Try
con.Open()
dsdata.Clear()
da.Fill(dsdata, "mytable")
con.Close()
Catch
Throw
End Try
And you can Bind your Control , mybe a Datagrid
like this
Try
datagrid1.DataSource = ds
datagrid1.DataMember = "mytable"
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
and Walla its Simple , Check my Articles about doing Database work without relying on Wizards. Wizards dont give you the Flexebility and they will never allow you to learn, as you say you are new to coding , you have to start coding and stop using Wizards
Hope this Helps
Vuyiswa Maseko,
Sorrow is Better than Laughter, it may Sadden your Face, but It sharpens your Understanding
VB.NET/SQL7/2000/2005
http://vuyiswamb.007ihost.com
http://Ecadre.007ihost.com
vuyiswam@tshwane.gov.za
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I have applied your method and it is working I am retrieving data from the database
THANK YOU VERY MUCH
Still working on how to change, update, add and delete records from the database though
where can I see your articles your sites are showing the "cpanel" page and not the actual content.
Will ask if get some other problem
Again Thanks
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Hi everyone, I'm focusing on a real tough problem that I hav been trying
to solve since a long time. I'm trying to detect the Open or close status
of the Cd drive door. I'm using mcisendstring function to query the
status, mcisendstring("Status CDAudio Mode"). This function returns
the following values accordingly:
"not ready", "paused", "playing", and "stopped" values.
Some devices can return the additional "open", "parked", "recording",
and "seeking" values.
If there is a cd in the drive and the door is closed then it's almost easy to identify as "status CDAudio mode" returns a value anything other
than "open". But the real problem is when the CD door is open the
value returned by the mcisendstring function is "open". Again when the
CD door is closed with no CD inside the function is returning the same
value "open". There's no way I can distinguish the CD tray status
programatically when the value returned is "open". Can anybody help
me? Is there any way other than the mcisendstring function to
query the CD door status? If yes then Plz provide me a code example.
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I imagine that all the system knows for sure is that there's no CD there. I am pretty sure there's an API to open the door, if there's no CD, you could open it, and then know it was open :P
Christian Graus
No longer a Microsoft MVP, but still happy to answer your questions.
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Yeah u r right, through the API I'm using for MCISendstring function, the system can identify whether a cd is present in the drive or not through the command- mcisendstring(Status CDAudio Mediapresent). It returns true or false accordingly. But to be precise, the problem lies during the absence of any cd. At that time the command- mcisendstring(Status CDAudio Mode) is returning the same value- OPEN regardless the open or close state of the tray door. Can U plz focus more on it? Thanx.
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hi all,
im using winsock array in vb6, i converted to vb.net 2005 platform...they created a axwinsockarray .dll.. my question is : it is useful using winsock in vb.net 2005 ?
until now the conversion is good .. but i don't know if it will be an error in futur by using winsock inside vb.net 2005 ....
can anyone help me thanks in advance.
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I believe winsock went the way of the dinosaurs in .Net. It was replaced by System.Net.Sockets Namespace[^], and on a high-level by TcpClient [^] and TcpListener[^].
So, I suggest migrating to one of those to make it easier and avoid any unnecessary problems.
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