|
is there any way to retrieve data from DataTable using regular SQL
statement, especially aggregate funcs like AVG(column) or SUM(column)
looks like DataTable.Select("AVG(column)") doesnt work, because it only uses
the agrument as a filter expr, not SQL
(i dont want to access the source database again using OleDBCommand, because the SQL command involves a few inner joins and it just takes too long)
manson
|
|
|
|
|
Look at the "DataColumn.Expression Property" in the help. It shows ways to use Aggregates and "DataView" has more information on filtering and sorting.
Rocky Moore
|
|
|
|
|
|
Hi,
Basically I'm trying to create a "selection rectagle" much like the one on the window's desk top when you click the desktop and move the mouse to select multiple icons.
I've thought of two ways to do this:
1) I'm tried to draw a rectagle as I drag the mouse around on a Form. I can draw a rectagle directly on Form but the problem is that any controls that are on the Form appear OVER the rectangle. -- Is there anyway I can get the rectagle to be on top of ALL the contols on the Form? Or can I create a Graphics region that overlays the Form (and all the controls on the Form) in such a way that this Graphics reagion is the "top most" region/window?
2) For my second attempt I created a UserControl and tried to make its background transparent. But this simply did not work. Is there any way to do this. If so then I could simply resize this control as the mouse moved and that would simulate a "selection area/rect".
OR maybe you have a third approach that I should try ( ? ) 
Thanks in advance!
|
|
|
|
|
albean wrote:
Or can I create a Graphics region that overlays the Form (and all the controls on the Form) in such a way that this Graphics reagion is the "top most" region/window?
Get a handle to the desktop and draw on that. Don't forget to clip the rectangle to your form window.
It sounds like your drawing on your form, doing an update which shows the rectangle and then the controls are being drawn on top of that. If that's the case, then you need to draw a rectangle using XOR and prevent the form and the controls from updating.
Todd Smith
|
|
|
|
|
Todd Smith wrote:
It sounds like your drawing on your form, doing an update which shows the rectangle and then the controls are being drawn on top of that. If that's the case, . . .
Todd,
Thanks for your time. Yes, your diagnosis is perfectly correct. I'm using the Graphics object of the Form and then using the DrawRectangle method.
Todd Smith wrote:
then you need to draw a rectangle using XOR
Do you mean that I should draw the rectangle in a new Region variable and then take this Region and XOR it w/ the graphics object of the Form?
------
Another problem that I’m having (using my previous incorrect method from my first post i.e. DrawRectangle) is that I need to erase the old rectangle as the user drags the mouse. So would it then be possible to take the Region that I just described above and XOR it again to erase the "superposition" of the rectagle on the form, and then repeat the process above with a "new" rectangle?
Thanks again.
|
|
|
|
|
Todd,
Thanks again for your time. I found this link that contains the solution to the problem I faced. Thanks again for your help!
http://support.microsoft.com/default.aspx?ID=KB;EN-US;Q314945&
|
|
|
|
|
How can I show the standard Windows dialog for choosing a folder?
|
|
|
|
|
|
This Project (Book Store Management System) have the necessary parts include:
# Employee's system - it will display who is taking care of the counter on that
particular day.
- this system will not keep track on the payroll of the
staffs.
# Stock Update System - it could update the amount of stocks.
# Sales system - it can help to keep track of how many items which have been
sold.
# Member system - it will store the member's detail whenever the customers want
to register as member of the book store.
- this system will be used by clerk only.
# Password Login - it is the essential component of the starting the system.
- This password login must not be a fixed one but indeed it
could change from time to time.
These 4 system will be handle by the cashier.
--------------------------------------------------------------------------------
This project actually is a free topic, so we, students are free to choose what we want.
--------------------------------------------------------------------------------
Thus, this project is my own idea. If you wish to add some ideas or commends, feel free to do so. I would appreciate it very much.
I hope you can understand my question.
Thank you.
Aaron
|
|
|
|
|
How do I hide a form on startup? Putting this.Hide() in Form1_Load() doesn't work. I guess the form is displayed after the load event fires.
|
|
|
|
|
There are many ways to do this, you can do something like this:
this.Opacity = (float)0;
HTH
Nick Parker
|
|
|
|
|
OK but what I really want to do is minimize to the system tray on startup. This.Hide() accomplishes this except on Form_Load(). Is there an event that gets fired only once AFTER the form is displayed?
|
|
|
|
|
|
Joel Matthias wrote:
though I guess it would work
Sometimes that's all it takes. 
Nick Parker
|
|
|
|
|
The window would still intercept clicks if you did this!
A translucent window is still listening for clicks on it's UI.
|
|
|
|
|
Christopher Lord wrote:
A translucent window is still listening for clicks on it's UI.
True, I guess I didn't know what the scope of the project was; I just said it would work!
Nick Parker
|
|
|
|
|
Have you tried starting up with the form minimized?
Also, this column might help:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dncscol/html/csharp06102002.asp
|
|
|
|
|
whats wrong with this? plain old java
[STAThread]
static void Main()
{
MainForm main = new MainForm();
main.Visble = false;
}
MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. 
|
|
|
|
|
Well that would certainly create a form that never becomes visible. Of course the application would also just exit.
|
|
|
|
|
|
why is a TopMost Form on top of all open windows in the system, instead of
being on top of only its application windows?
man
manson
|
|
|
|
|
It's a windows style. Not necessarily unique to the .net framework. Topmost means that the window won't be covered by any other windows. Check the win32 api for more info.
|
|
|
|
|
If you want a form to always be on top of a particular Form, you can set the Owner property on the form that should appear on top to the one that should appear below. Alternatively you can call AddOwnedForm(ownedForm) to do the same.
ie, FormA should always be on top of FormB
FormB.AddOwnedForm(FormA);
James
"And we are all men; apart from the females." - Colin Davies
|
|
|
|
|
James T. Johnson wrote:
, FormA should always be on top of FormB
Cool I didn't know that.
C# is fundamentally broken. - Christian Graus
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
was bit quick there 