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ServiceBase.OnStart and ServiceBase.OnStop are meant for initialization and destruction of your service, respectively. They should be as fast as possible, as you've seen. Instead, push all work into a separate thread and simply start the thread.
class MyDbService : ServiceBase
{
public override void OnStart(string[] args)
{
Thread t = new Thread(new ThreadStart(UpdateDb));
t.Name = "Db Updater";
t.Start();
}
public override void OnStop()
{
}
void UpdateDb()
{
}
}You might also consider using a ThreadPool and splitting up units of work based on your inputs and number of connections available from the client to the database. If the database implements connection pooling (depends on connection string options, typically) and a client can open a number of connections to the same database you could get a lot of performance boosts this way.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Customer Product-lifecycle Experience
Microsoft
[My Articles] [My Blog]
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Hello....
I'm stuck on a piece of logic that i'm sure is pretty simple but i've been thinking about it so long now that my mind has literally stopped working....
With that said...
I am writing events to a log file that i then need to turn around and once a day backup-or move to the db.
Once i begin moving to the db i need to parse the separate fields (date/time, user, event message, priority, etc) into separate columns.
Yes, I am fully aware that it would be easier to just write it to the db from the begining...but every action we call is already going to the db so it doesn't need to be contending with event logs.
So, due to the format of my log files i need to read until "- -" for instance: {username}- -{Event Message}- -{etc...} i then need to send that data to the db to the independant columns.
This of course poses two problems, at least that i can see..first being how do i safely parse the string until i hit the "- -"(i am willing to change that to something more unique if necessary).
and Second...
how do i quickly deposit this to the db? I am doing this at night when 90% of our clients will be closed, but there is that small amount of sites that run 24/7, so it doesn't need to interupt their operations!!!
(oh, by the way i've got about 5 logs to send over and they normaly are 100+k each daily)
string Beautiful;
Beautiful = "ignorant";
label1.Text = "The world is full of " + Beautiful +" people.";
Why is common sense such an un-common comodity?
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1. If you would reduce it to one special chcracter you can spplit the whole string via string.Split('|') into smaller pieces without having to parse anything.
2. The fastest way greatly depends on your database type. But rethink if you really want it fast: Is it probably better to make it a bit slower, so that the database or any other processes can also answer other requests in the meanwhile? For this a seperate thread with low priority could be usefull.
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I wouldn't worry if you mean 100+KB per day, because that is quite small. If you mean 100+K records, then it could take a while. Just read each line, split it with split('- -'), and shove it into the database using a stored procedure. On a moderate single processor machine running sql server, you should easily get 1000 records per second. A very slow server may take up to 5 times longer.
Try the simple approach first, then optimize later. If you DO need to optimize, look to sending batches of inserts in each command, or passing your data as strings into a stored proc and parsing them out in there. Usually, these extremes are not necessary.
Simple approach:
StreamReader sr;
String str;
String[] arr;
String delim = "- -";
SQLCommand cmd;
SQLConnection cn;
//init connetion and command here and open connection
//open streamreader here
str = sr.ReadLine;
while (sr.Peek() >= 0)
{
arr = str.Split(delim.ToCharArray());
cmd.Parameters("@Param1").Value = arr[0];
...
cmd.ExecuteNonQuery();
}
cn.close;
sr.close;
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Hi,
I am working on a project to come out with new ways of sending video streams over a network, and I was wondering if this scenario is possible in c#.
I load a avi file on a server using directx managed lib, send the video to the client threw tcp and read the sent data from memory without writing it to the HD pass it threw the some directx classes, and start playing the video before it is totally downloaded.
I am pretty good in network programming but have just started investigating video codec and playback
Any article, web site, book, tutorial, or code snippet would be greatly appreciated.
thx
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I have just dabbed on this stuff, but AFAIK, you would need:
1. a stream compatible media, eg wmv, asf, mpeg2, mpeg. NOT a generic wrapped avi file, unless u can handle it somehow in part (2).
2. Input and output Directshow filters to handle the transport. Unfortunately I have not seen any source for things of this kind, but I have in some commercial products. It cant be that hard to write though, if you have some background knowledge.
I suggest you look at the DirectShow MSDN docs. They part of the Platform SDK docs.
And finally when you did it, write an article please  I would love to see it in action!
xacc-ide 0.0.99-preview4 now with C#, C, IL, XML, Nemerle and Boo highlighting support!
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Okay, I have a better question.
How do you make a dataset persist between page refreshes without executing your query over and over?
Thanks.
SD
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Simplest approach I'd have thought was to store the dataset in the Session:
private void Page_Load(object sender, System.EventArgs e)
{
// try to retreive an existing dataset from the Session
DataSet dataSet = (DataSet)Session.Contents["myDataset"];
// if there isn't one
if (dataSet == null)
{
// create it
dataSet = new DataSet();
// populate the dataset
// ...
// add it to the session, ready for retrievel next time
Session.Contents.Add("myDataset", dataSet);
}
// do stuff with the dataset here
}
Rob Philpott
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Rob,
thank you for the response. This sounds like exactly what I want. However, I tried this and I keep running into a problem. First, I whipped up a simple dataset in the Global.ASAX file. Then, I debugged it on a page load.
When my page loads, the localDS is set to a new DataSet (per the code snippets below); however, line 103 executes and the localDS becomes <undefined value="">. So, what do you think is wrong with...
???localDS = (DataSet)Session.Contents["ds"];
Is there something special that is done in the declaration of ds in the GLOBAL file?
Thanks.
William
protected void Session_Start(Object sender, EventArgs e)
{
DataSet ds = new DataSet();
DataRow dr;
ds.Tables.Add("Test");
ds.Tables[0].Columns.Add();
ds.Tables[0].Columns[0].ColumnName = "Name";
ds.Tables[0].Columns.Add();
ds.Tables[0].Columns[1].ColumnName = "ID";
dr = ds.Tables[0].NewRow();
dr[0] = "Test1";
dr[1] = 1;
ds.Tables[0].Rows.Add(dr);
dr = ds.Tables[0].NewRow();
dr[0] = "Test2";
dr[1] = 2;
ds.Tables[0].Rows.Add(dr);
...
100 private void Page_Load(object sender, System.EventArgs e)
101 {
102 DataSet localDS = new DataSet();
103 localDS = (DataSet)Session.Contents["ds"];
...
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Your code doesn't show where the newly created Dataset in Session_Start is added to the Contents dictionary (the Session.Contents.Add line in my original reply) - you may have left that bit out the code snippet - how are you doing this?
If the dataset isn't being added to the dictionary after its populated, we can't access it later, so that might be the problem.
Also, in line 102 it makes no sense to construct a new dataset, because in the next line localDS is either going to end up (hopefully) referencing the pre-created dataset or null if it can't find it, not the new DataSet you create on line 102.
Rob Philpott.
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Rob,
first, let me really thank you for assisting so much. Problem solved because of your additional questions...
Your right, line 102 wasn't useful...I was just grabbing at straws.
The answer was, I did not realize that you had to add the dataset to the session dictionary with an "alias" name in order to access it: Session.Contents.Add("Myds", ds);
Thank you again...the code below works fine!
William
private void Page_Load(object sender, System.EventArgs e)
{
DataSet localDS = (DataSet)Session.Contents["Myds"];
dd1.DataSource = localDS;
dd1.DataTextField = "Name";
dd1.DataValueField = "ID";
dd1.DataBind();
...
protected void Session_Start(Object sender, EventArgs e)
{
DataSet ds = new DataSet();
DataRow dr;
ds.Tables.Add("Test");
ds.Tables[0].Columns.Add();
ds.Tables[0].Columns[0].ColumnName = "Name";
ds.Tables[0].Columns.Add();
ds.Tables[0].Columns[1].ColumnName = "ID";
dr = ds.Tables[0].NewRow();
dr[0] = "Test1";
dr[1] = 1;
ds.Tables[0].Rows.Add(dr);
dr = ds.Tables[0].NewRow();
dr[0] = "Test2";
dr[1] = 2;
ds.Tables[0].Rows.Add(dr);
Session.Contents.Add("Myds", ds);
...
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No problem - glad to help
Rob Philpott
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I have a set of XML files that I parse & put into a dropdown list. I don't want to read this set of files off the network every time the page loads.
I was considering establishing a data set in the GLOBAL.ASAX file in the Session section.
I would just bind that dataset on the page load for this one dropdown where it occurs in the application. NOW, I know I will hear some "purist" objections to using anything that sounds like a global variable, but it seems far more efficient than reading 100+ XML files every time the page loads for every user.
I have tried creating a dataset in the Session_Start, but it isn't clear how I would access it.
Any thoughts?
Also, I am curios if there is an equivalent to a variable declared on a page in VB "Public Shared MyInt As Integer"?
Thanks.
SD
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I found the answer to my tranlation question. There is a nice site that does translations back and forth between VB & C#: http://www.carlosag.net/Tools/CodeTranslator/Default.aspx; however, I would still be interested in any response to my GLOBAL question.
Thanks again,
Sd
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Forget it. This was a bad question. I simply put a public dataset on the page of interest and read the XML into the dataset on if (!PostBack).
Thanks anyway.
Sd
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I've written a small C# assembly which does MX/ANAME lookups on a DNS server to get a list of mail servers/IP addresses for a particular domain, but I'm having some bother in programmatically finding out the IP address of the DNS servers to query. Currently I've hardcoded the IP of two BT DNS servers after looking them up on my DSL router. 
Is there a way to find out the IP address(es) of the computer's DNS servers in .NET, and in particular in managed code without resorting to P/Invoke as I try to make my code work with Mono. I've trawled the net and had no luck in finding this out. 
I would be most grateful to any genius who could show me the (a) way. Thank you!
Rob Philpott.
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Thanks for the response leppie,
I could attempt something of the sort, but on Windows the DLL I'd need to talk to I believe also does MX and ANAME lookups too, making the whole project kind of redundant.
I really need a managed code solution, but I have doubts about whether one exists.
Rob Philpott
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I need to validate text as nunber for 4 TextBoxes. Here is some code I wrote to validate the first TextBox, but this code locks me in the TextBox-- also
although it will handle an error the App won't close and again, I'm "frozen" in this text box. Thanks a lot.....
try
{
cmplxValue1.Real = Convert.ToDouble(textComplex_1Real.Text);
//cmplxValue1.Imaginary = Convert.ToDouble(textComplex_1Imaginary.Text);
}
catch(Exception ex)
{
error = true;
}
finally
{
if(error)
MessageBox.Show("Error");
textBox1.SelectAll();
textBox1.Focus();
e.Cancel = true;
}
}
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I read RTFM and still don't get it.
e.Cancel = true; means nothing out of context
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Wy not read the answers you got when you posted the question only 16 hours earlier, instead of posting it again?
---
b { font-weight: normal; }
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While I am grateful for any response...I read them and they donn't work.
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