Entries for ploe

SQL Query...can't seem to wrap my head around this [SQL Query...can't seem to wrap my head around this]

ploe — Mon, 21 Sep 2009 18:39:36 GMT

I feel like there exists a query that returns the data I'm looking for. I just can't seem to get my brain to tell me what it is :P Perhaps I've been staring at it too long. Any help would be appreciated :)

Let's say you have a table called WINDOW that has a START date, an END date and a unique ID.

I want to select all the rows that are within 10 minutes of each other and at least one of the rows falls within a given datetime (which I pass in my query).

Here's a sample dataset:

ID, START, END

1, 9/21/09 00:00:00, 9/21/09 00:30:00

2, 9/21/09 00:38:00, 9/21/09 02:00:00

3, 9/21/09 02:05:00, 9/21/09 04:00:00

4, 9/21/09 04:15:00, 9/21/09 04:30:00

5, 9/21/09 04:35:00, 9/21/09 07:30:00

Rows 1 -> 2 -> 3 are a set because 2's START is only 8 minutes greater than 1's END and 3's START is only 5 greater than 2's END. Following that rule, 4 and 5 are a set as well.

Passing in the datetime 9/21/09 02:00:00 should return rows 1, 2, and 3 because that time falls within the min and max time those 3 rows cover. If I were to pass in 9/21/09 04:20:00, I would expect rows 4 and 5 to be returned.

I started with this query, but that's only going to return rows 2 and 3 (the immediately adjacent rows), not N rows.

SELECT * FROM WINDOW WHERE ABS(DATEDIFF(mi, END, '9/21/09 02:00:00')) <= 10 OR ABS(DATEDIFF(mi, START, '9/21/09 02:00:00')) <= 10

And I tried another approach, but this will return rows 4 and 5 too when I only want 1, 2, and 3 :(

SELECT * FROM WINDOW w WHERE EXISTS(SELECT TOP 1 ID FROM WINDOW w2 WHERE w2.ID != w.ID AND ABS(DATEDIFF(mi, w2.END, w.START)) <= 10 OR ABS(DATEDIFF(mi, w2.START, w.END)) <= 10)

Grr

in reply to SQL Query...can't seem to wrap my head around this

Add form in another appdomain to mdi container [Add form in another appdomain to mdi container]

ploe — Mon, 12 Jan 2009 19:34:20 GMT

Our plugin model isolates plugins in their own AppDomain so that if a plugin crashes it doesn't take down our whole client app. This also allows for us to unload and load plugins if we choose to. The problem I've run into is now it's much harder to show my plugins (each have their own windows Form) in my main mdi window. :(

So I thought, why not pass the handle to the main window since I can pass primitives accross AppDomains? I then implemented a method in the main window where you pass in the plugin handle and it shows it in the main mdi window. Here's my code:

uint style = GetWindowLongPtr(formHandle, GWL_STYLE);
style &= ~WS_POPUP;
style = style | WS_CHILD | WS_VISIBLE;
SetWindowLong(formHandle, GWL_STYLE, style);
SetParent(formHandle, this.Handle);

This approach seems to be buggy though...
1. The title bars of plugin windows always appear inactive as if the window was not in focus
2. When I maximize a plugin window, it does not seem to be aware that my main window has a menu and toolbar docked to the top. The maximized plugin window sits right over the top of them
3. And worst of all plugin windows are always on top of the other managed windows :(

Has anyone successfully been able to get this working correctly? Or is there some other way I can do this?

It seems like a managed MdiClient is not aware of the native child windows that I've added...

in reply to Add form in another appdomain to mdi container

Tell Windows that my program is responding [Tell Windows that my program is responding]

ploe — Wed, 12 Nov 2008 21:41:25 GMT

So I have this c++ console application that takes a while to close. In my SetConsoleCtrlHandler handler I have to write some things to disk before my program can closes. So when you close my application the End Program dialog comes up because Windows thinks my application is not responding. Is there a way for me to tell Windows "hey I am still responding, it just takes me a while to close"?

in reply to Tell Windows that my program is responding

SQL IX lock [SQL IX lock]

ploe — Wed, 01 Oct 2008 00:45:44 GMT

I have a SQL view that grabs data from various tables. One of those tables is table Y. The view is kinda slow and while the view is running I am unable to run any update statements on table Y. So I ran a stored procedure to view the current locks on the SQL server while the view is running. There was an IX lock on table Y. Now this view is only used to "View" data; why would the SQL server lock that table while it's running? Is there anything I can do to prevent this from happening? :/

in reply to SQL IX lock

DateTime and DST [DateTime and DST]

ploe — Thu, 28 Aug 2008 15:43:45 GMT

Does the .net DateTime struct consider DST?

Lets say I have a DateTime dt that is set to a date two hours before we set our clocks forward. Then I add 5 hours to dt. Would the DateTime add function consider DST or would the add be an hour off?

in reply to DateTime and DST

Get stack trace of a ThreadPool Thread [Get stack trace of a ThreadPool Thread]

ploe — Thu, 07 Aug 2008 22:34:03 GMT

I have a C# server application that's stuck in a loop somewhere; after a while the process just constantly uses 13% CPU (1 core). I'm pretty sure it's one of my ThreadPool threads that's doing this; some command sent by the client eventually triggers this infinite loop.

I've looked at the StackTrace object as a stack trace would definately help me find the code that's causing this. There is a constructor that allows me to pass in a Thread object to get the stack trace of the passed in thread however I don't have a Thread object because it's a ThreadPool thread.

Do you know any way that I can get a stack trace of a ThreadPool thread?

I am able to identify the thread that is looping by printing out all the threads and finding the one that has taken up the most CPU time. However I can't seem to use the information from the code below to get a stack trace.

foreach (System.Diagnostics.ProcessThread thread in System.Diagnostics.Process.GetCurrentProcess().Threads) {
    Console.WriteLine("ID: {0}", thread.Id);
    Console.WriteLine("Start Time: {0}", thread.StartTime);
    Console.WriteLine("State: {0}", Enum.GetName(typeof(System.Diagnostics.ThreadState), thread.ThreadState));
    Console.WriteLine("Total Proc Time: {0}\n", thread.TotalProcessorTime);
}

Any suggestions? :(

in reply to Get stack trace of a ThreadPool Thread

C# EventHandlers... [C# EventHandlers...]

ploe — Wed, 25 Jun 2008 14:04:39 GMT

Is there a difference between these two lines?

button.Click += new EventHandler(OnButtonClick);
button.Click += OnButtonClick;

Both compile and work from what I can see. Do they behave differently? Is one preferred over the other?

in reply to C# EventHandlers...

C# parameter passing... [C# parameter passing...]

ploe — Thu, 22 May 2008 14:51:59 GMT

I pass in an object to a method. This method modifies some properties of the object. After the method returns the changes it made to the object seem to have disappeared as if the object passed in was passed by value rather than reference.

Is there any instance where C# would do such a thing?

This is how I would like write my code:
ResetStopTimes(stops, loadTimes);

private static void ResetStopTimes(Stop[] stops, Dictionary<int, TimeSpan>) { ... }

I need to write my code like this in order to get the changes out of the function:
stops = ResetStopTimes(stops, ref loadTimes);

private static Stop[] ResetStopTimes(Stop[] stops, ref Dictionary<int, TimeSpan>) { ... }

It's wierd as most places I don't need this hack. It behaves like I would expect it. Anyone know what's going on here?

in reply to C# parameter passing...

I'm stumped... [I'm stumped...]

ploe — Fri, 16 May 2008 17:40:53 GMT

I've been thinking about this problem for a while and don't know how to solve it without using strings...

The method looks like this...
double Format(double d, double precision)
{
...
}

d is the double I want to format and precision is how it needs to be formatted

for example:
d = 2.06
precision = 1.0
returns: 2

d = 36.04
precision = 1.0
returns: 6

d = 36.04894
precision = 2.3
returns: 36.048

It's only a few lines of code if I convert the two parameters to strings, but I feel like there must be a mathematical approach to solve this problem too...any ideas? :|

in reply to I'm stumped...

c++/cli xmldoc intellisense support? [c++/cli xmldoc intellisense support?]

ploe — Sun, 27 Jan 2008 07:05:43 GMT

I was toying around with a C++/CLI project in VS2005 and noticed that xml comments '///' don't seem to work like they do in c#. :(

So I thought perhaps there just isn't intellisense support for '///' in the language so I manually put xml comments in my class. But I noticed when using the class I just commented (in another C# project) that the comments do not show up in intellisense. Is there something I doing wrong or does C++/CLI not support this sort of documentation?

in reply to c++/cli xmldoc intellisense support?

Broken try catch [Broken try catch]

ploe — Sun, 06 Jan 2008 22:34:27 GMT

I wanted a more user friendly experience when this C# app crashes. So I wrapped all the code in Main() in a try catch to handle any unhandled exceptions. Inside the catch I show an error reporting dialog where the user has the option to report the error.

So I assumed that all unhandled exceptions would end up in this catch block, but it doesn't seem to be the case. On some machines the catch block doesn't catch the exception and the standard .NET exception dialog pops up.

So is there any instance where a try catch wouldn't catch an exception?

Just a side note: All machines that this is tested on have .NET 2.0 SP1. The two machines that do not catch the exception have server 2003 installed.

in reply to Broken try catch

Prevent combobox from closing... [Prevent combobox from closing...]

ploe — Fri, 23 Nov 2007 22:00:19 GMT

So I'm trying to prevent a ComboBox from closing it's dropdown after an item is selected. I can't seem to figure it out.

I tried overriding WndProc and listening for CBN_CLOSEUP, but have found that that notification is called after the dropdown closes, not before. I've also tried CBN_SELENDOK. Does anyone have any other ideas?

in reply to Prevent combobox from closing...

Operator overloads in C# and generics [Operator overloads in C# and generics]

ploe — Wed, 31 Oct 2007 04:18:20 GMT

I'm trying to do an explicit operator overload on a generic class and am not seeming to have any luck. Is the following possible? Is there some other approach I should try that acheives the same thing?

Field<string> f = "some test"; //this works fine
string s = f; //compiler doesn't like this line

public class Field<T> {
   public T Value {
      get { return m_Value; }
      set { m_Value = value; }
   }
   private T m_Value;
   public Field() { }

   public static implicit operator Field<T>(T value) {
      Field<T> field = new Field<T>();
      field.Value = value;
      return field;
   }

   public static explicit operator T(Field<T> field) {
      return field.Value;
   }
}

in reply to Operator overloads in C# and generics

C# Designer Property Confusion [C# Designer Property Confusion]

ploe — Wed, 27 Jun 2007 23:33:13 GMT

I have defined an interface called ICustomControl that all of my controls implement. One property in the interface is...

bool LockControl { get; set; }

This property exists so that I can iterate through a collection of ICustomControls and lock them or unlock them. The definition of "locking" a control is control specific.

For a textbox the property looks like this...
public bool LockControl { get { return ReadOnly; } set { ReadOnly = value; } }

For most controls the property looks like this...
public bool LockControl { get { return !Enabled; } set {Enabled = !value; } }

When in the designer I am able to change the LockControl property of a textbox and the ReadOnly property changes along with it. This does not work for controls whose LockControl property tries to change the Enabled property. In fact, the designer does not even allow me to change the value of LockControl.

Is there an attribute I have to put on the property to get this to work correctly in the designer?

in reply to C# Designer Property Confusion

LINQ Book [LINQ Book]

ploe — Sat, 14 Apr 2007 03:57:24 GMT

Can anyone recommend a good book on LINQ? I would like to learn as much as I can about it as I would like to consider using it for a project.

in reply to LINQ Book

300 [300]

ploe — Sat, 10 Mar 2007 08:19:18 GMT

300 was good I suggest you go see it :D

in reply to 300

SP1 for VS2005 install [SP1 for VS2005 install]

ploe — Fri, 09 Mar 2007 02:38:10 GMT

Anyone else find the SP1 install to be very slow? It has been "Gathering Information" for about an hour.

msiexec is @ 100% cpu usage :(

I've found forums with people having the same problem but no solution. Is there a fix?

in reply to SP1 for VS2005 install

Bill's view on Apple ads [Bill's view on Apple ads]

ploe — Sun, 04 Feb 2007 17:46:10 GMT

I've always wanted to know what Bill thought about the Apple ads. I guess this article I found says it all...

“And I don't know why [Apple is] acting like it’s superior. I don't even get it. What are they trying to say?” Gates continues to express his disgust with the Apple ads: “Does honesty matter in these things, or if you're really cool, that means you get to be a lying person whenever you feel like it? There's not even the slightest shred of truth to it.”

http://www.dailytech.com/article.aspx?newsid=5957

in reply to Bill's view on Apple ads

A question for the ages/people good with SQL [A question for the ages/people good with SQL]

ploe — Wed, 10 Jan 2007 21:44:27 GMT

I have this table (CustomerTripTaken) that holds the ID's of customers that have taken trips. I created a SQL trigger on the Trip table that inserts the customer id into this CustomerTripTaken table.

Here's the trigger...
create trigger TripTrigger
on Trip for Insert, Update as
if update(Customer) begin
   decare @id int
   select @id = (select Customer from inserted)
   if not exists(select CustomerID from CustomerTripTaken where CustomerID = @id and UpdateType = ‘CHECK’) begin
      insert into CustomerTripTaken (CustomerID, UpdateType)
      values (@id, ‘CHECK’)
   end
end

My problem is that when looking in the CustomerTripTaken table there are no rows of UpdateType 'CHECK'. This makes no sense because when looking at recently created trips the Customer column is not null; it in fact has a customer id in it. So how does Customer get filled in on the Trip table without my trigger knowing about it? Ugh.

in reply to A question for the ages/people good with SQL

can someone explain fair use to me [can someone explain fair use to me]

ploe — Sun, 24 Dec 2006 02:15:43 GMT

So I created a sports video of my favorite team consisting of highlights put to music.

The video was rejected by Google Video citing violation of copyright. This is odd because I uploaded an almost identical video in May with no problem.

What I don't get is why a collection of highlights put to music is copyright infringement. Isn't this just "fair use"? It's not like I'm making money on it. [C]

Am I not allowed to legally create a sports video using music and hightlights I like and share it with other fans? If the answer to this is no, something needs to change.

in reply to can someone explain fair use to me

get sql statements being executed... [get sql statements being executed...]

ploe — Tue, 19 Dec 2006 22:01:53 GMT

I am writing a little c# app, but right now I'm stuck. [C]

I would like to capture all of the SQL statements that are being executed on my SQL 2000 server.

Basically when a SQL statement is executed I want the statement sent to my app. If "select * from Customers" is executed then the string "select * from Customers" should be passed to some function in my app.

If I can't this data in an event based way, is there some data source on the server I could constantly poll? Perhaps a system table or log file?

I've looked at notification services, but it looks like it provides data not raw queries.

Any help would be appreciated. Thanks.

in reply to get sql statements being executed...

Buffalo 0; God 1 [Buffalo 0; God 1]

ploe — Thu, 19 Oct 2006 19:25:10 GMT

I got back my internet/cable yesterday after a storm that hit on Thursday (10/12) evening. Aparently two and a half feet of snow is destructive. :P

The real destuction was to the trees which in turn left about 200,000+ households without power. The leaves haven't fallen yet which caused the trees to accumulate too much snow and collapse. There are still 63,000 people without power.

Luckily we didn't lose power and heat. Guess what that means? The whole family stayed with us. :(

Here are some photos of the destruction:
http://newstrackerstormphots.blogspot.com/

To no surprise, FEMA is late; they arrived yesterday. :@

in reply to Buffalo 0; God 1

can someone explain this product to me...? [can someone explain this product to me...?]

ploe — Tue, 03 Oct 2006 21:15:58 GMT

http://www.ncomputing.com/ncomputing/solutions/overview.php

I just don't get it. First of all it seems too good/cheap to be true.

I don't understand how it doesn't violate MS licensing. Wouldn't you need an OS license for each user? And if you are running it off a server wouldn't you need terminal server CALs? I must be missing something.

UGH. :s

in reply to can someone explain this product to me...?

i can't seem to find... [i can't seem to find...]

ploe — Sat, 16 Sep 2006 18:33:14 GMT

I am looking for a good PDA; mine's on its last legs. Why can't I find one with a built in camera that is not a phone??? [C]

If someone could point me to such a device I would go from this [C] to this :D

in reply to i can't seem to find...

Apple opens up kernel [Apple opens up kernel]

ploe — Tue, 08 Aug 2006 21:51:40 GMT

So I guess Apple released their kernel source of OS X.
http://www.dailytech.com/article.aspx?newsid=3718
http://www.opensource.apple.com/darwinsource/10.4.6.x86/

I am unsure if this is good for Apple or bad. Will it hurt MS at all?
Thoughts?

in reply to Apple opens up kernel