Re: GDI Resource Issue - C / C++ / MFC Discussion Boards

Re: Firewall

Philip Fitzsimons22-Aug-02 23:05

Philip Fitzsimons

22-Aug-02 23:05

http://www.opensourcefirewall.com/[^]

"When the only tool you have is a hammer, a sore thumb you will have."

An ADO question

Anonymous22-Aug-02 18:22

Anonymous

22-Aug-02 18:22

Suppose we execute a SQL query that returns various fields. Now in order to get value of certain field we use following methods:

vtField = pRecordset->Fields->GetItem("Name")->Value;
OR
vtField = pRecordset->GetCollect("Name");

But there are certain queries that do not return any field but a single value e.g

select count(userid) from mytable

Suppose i execute this query and its result is in RecordSet object. Now how can i retrieve this value as this is a single value and is not represented by any field ????

Re: An ADO question

Todd Smith22-Aug-02 18:43

Todd Smith

22-Aug-02 18:43

Try

select count(userid) as count from mytable

vtField = pRecordset->GetCollect("count");

Todd Smith

floats and doubles/Visual Studio C++6

dlm444422-Aug-02 17:33

dlm4444

22-Aug-02 17:33

How can I do decimal precision in an edit control? For example, .002 or 2E3 or 2E-3. I just can't find a way to get the decimal precision I would like and Setprecision(4) should give me 4 places past the decimal but it doesn't work(I would like for every thing to be in engeering mode.) Help!

Frown | :(

David

Re: floats and doubles/Visual Studio C++6

Paul M Watt22-Aug-02 18:52

Paul M Watt

22-Aug-02 18:52

You will have to manage the data yourself, Win32 does not provide any extra processing for numbers and things like that.

If you simply want the data to be displayed in a particular format you can wait for the edit control to lose focus then reformat the data yourself from the parent control.

However if you want to limit the characters that the user can type in and the format of their text you will have to do something a little more complicated. I would suggest subclassing the edit control to limit these characters.

Before you do that though I would search through this site and the internet, someone else has probably already created a control like this that you could use.

Good Luck

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

GDI Resource Issue

Stew22-Aug-02 17:31

Stew

22-Aug-02 17:31

So, I figured out what I was doing with the GDI resources and everything works fine in 2000, NT, XP, and 98 SE. The only problem is, I'm getting the GDI resources running out when I run my app on straight up windows 98. Does anyone know what I need to get to be able to update the Straight Up version of 98 to have the GDI fix or whatever in it without having to purchase the SE? I don't want to tell my customers that they have to buy an upgrade to their OS just to use my app.

Re: GDI Resource Issue

Tomasz Sowinski22-Aug-02 22:26

Tomasz Sowinski

22-Aug-02 22:26

Are you sure your GDI objects are not selected into any DC when you're deleting them?

Tomasz Sowinski -- http://www.shooltz.com

"Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation.

Re: GDI Resource Issue

Matthew R. Miller23-Aug-02 5:13

Matthew R. Miller

23-Aug-02 5:13

Restoring is key...

<br />
	// Declare variables<br />
	CPaintDC dc(this);<br />
        CPen *pOldPen;<br />
        CPen pPen;<br />
<br />
	// Create brushes and pens<br />
	CPen pPen(PS_SOLID, 1, RGB(0, 0, 255));<br />
<br />
	// Use pen<br />
	pOldPen = (CPen *) dc.SelectObject(&pPen);<br />
<br />
	// Restore the old GDI objects<br />
	dc.SelectObject(pOldPen);<br />

<><><><><><><><><><><><><><>
Matthew R. Miller
mattrmiller@computersmarts.net
www.computersmarts.net

How to create a callback function?

duen22-Aug-02 17:25

duen

22-Aug-02 17:25

What's the callback function?
When we need the callback function?

Re: How to create a callback function?

Todd Smith22-Aug-02 18:01

Todd Smith

22-Aug-02 18:01

duen wrote:
When we need the callback function?

Usually in response to a homework question.

Todd Smith

Re: How to create a callback function?

Matthew R. Miller23-Aug-02 5:15

Matthew R. Miller

23-Aug-02 5:15

Usually a callback function is to do the same task over and over again but passing it different variables to get different results each time. Like enumerating which fonts are on the users computer.

But callback can be used in more ways then just this.

<><><><><><><><><><><><><><>
Matthew R. Miller
mattrmiller@computersmarts.net
www.computersmarts.net

Date class question

philll22-Aug-02 17:22

philll

22-Aug-02 17:22

Hello all,

How do you create a date class that has the following date output formats--
DDD YYYY
MM/DD/YY
January 1, 2000

Thanks for the help,

Philll Confused | :confused:

Re: Date class question

C^hris L^osinger22-Aug-02 17:25

C^hris L^osinger

22-Aug-02 17:25

copy CDate

Though the cough, hough and hiccough so unsought would plough me through,
enough that I o'er life's dark lough my thorough course pursue.
--Stuart Kidd

image effects!

Re: Date class question

philll22-Aug-02 17:29

philll

22-Aug-02 17:29

copy cdate??

I'm lost.

Re: Date class question

C^hris L^osinger22-Aug-02 17:33

C^hris L^osinger

22-Aug-02 17:33

CDate has all those output formats.

maybe i misunderstood the question... ?

Though the cough, hough and hiccough so unsought would plough me through,
enough that I o'er life's dark lough my thorough course pursue.
--Stuart Kidd

image effects!

Re: Date class question

philll22-Aug-02 17:41

philll

22-Aug-02 17:41

Sorry. I need help creating the DATE class itself.

Which STL container to choose?

ns22-Aug-02 16:50

22-Aug-02 16:50

I have some undetermined number of values a field can take on. I need to gather these in an STL container, after which I have to check and see if a new value thats being added (to a database) already exists in the container. If it does, then I have to inform the user its not unique, and not add it to the db. (I'm not adding the new value to the STL container, but to a database, whose current values I've gathered in my container).

The value is a CString. Should I choose vector, or set or list (not a map for sure). I'll be checking to see if a CString exists in the container, not by index but by its name.

Suggestions?
Thanks,
ns

Re: Which STL container to choose?

Todd Smith22-Aug-02 17:19

Todd Smith

22-Aug-02 17:19

A vector is good if your array isnt changing size a lot. A list is good if your array changes size a lot. A list also costs you a tad bit more memory than a vector for the extra pointer.

If you want to do fast string searches then you need a hash. The map container is a hash. There are also some non-standard hash containers you can get. The boost library should have a few hash containers http://www.boost.org[^].

Todd Smith

Re: Which STL container to choose?

Paul M Watt22-Aug-02 19:15

Paul M Watt

22-Aug-02 19:15

I would choose a set.

A set will only allow one instance of the type that specify to be inserted. Use the insert member function of the set to insert the CString in the set.

The insert function returns a pair<set<CString>, bool> object to indicate if the function succeeded or not. THe iterator will contain the iter of the object that was inserted, and the bool will indicate if the insertion actually occured.

If the insertion occured then true will be returned, otherwise if the item already existed the bool will be false.

The standard implementation of a set is with a Red-Balck tree, which is a balnaced binary search tree. So you will get n log(n) lookup times. If you would rather use a hash implementation you can switch to the SGI or Boost implementations which both have hash implementations. Hash implementations have faster lookups than trees, however they require more space as well.

Good Luck.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Which STL container to choose?

Tomasz Sowinski22-Aug-02 22:16

Tomasz Sowinski

22-Aug-02 22:16

kilowatt wrote:
So you will get n log(n) lookup times

Isn't that just log(n) for lookup?

Tomasz Sowinski -- http://www.shooltz.com

"Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation.

Re: Which STL container to choose?

Paul M Watt22-Aug-02 22:47

Paul M Watt

22-Aug-02 22:47

Tomasz Sowinski wrote:
Isn't that just log(n) for lookup?

Your right, I confused the lookup time with the amount of time it takes to sort the entire binary tree.

Thanks

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Thanks everyone!

ns23-Aug-02 3:05

23-Aug-02 3:05

Thanks for the ideas. I am implementing this this morning so I'm glad for some direction with your responses.
ns

can I have two command objects w same connection?

ns22-Aug-02 16:34

22-Aug-02 16:34

Is this okay to do:

m_pCommand->ActiveConnection = m_pConn;

m_pCommand1->ActiveConnection = m_pConn;

So can the active connnection be reused like this?

Thanks,
ns

Re: can I have two command objects w same connection?

Le centriste22-Aug-02 18:18

Le centriste

22-Aug-02 18:18

I'm pretty sure you can.

Michel

It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a very long time to say, and to listen to.

- TreeBeard

Thanks for your responses.

ns23-Aug-02 3:08

23-Aug-02 3:08

Good to know. Thats one less bit of work! I do find that I have trouble reusing the same Recordset object with different commandTexts, so generally end up creating a new rs object for each iunrealted query. For some reason, if I used it the first time with command A, the come back later and try to use it with command B, it crashes.

Thanks for the answers,

ns

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