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I need to translate the following C++ code to C#
for (int i = 0; i < sizeof(mnX)/sizeof(float); i++)
{
mnX[i] = 0f;
}
where (in C#)
float[] mnX = new float[2];
Using this line as it is in C# results in a compile error which says that "sizeof" can be used only in an unsafe context.
I changed the line to the following:
for( int i = 0; i < System.Runtime.InteropServices.Marshal.SizeOf(mnX)/sizeof(float); i++ )
{ mnX[i] = 0f; }
which, of course, still results in the same error.
My question is this: when I tried to use
System.Runtime.InteropServices.Marshal.SizeOf(float), that resulted in a compile error as well.
I don't want to wrap this block of code with the *unsafe* keyword and then compile using /unsafe.
What would be my best option?
Thanks!
// Added 4:00PM PDT
I guess I could just replace sizeof(float) with 4. Still, just for the sake of knowing how, I'd like to know how to get around the problem. 
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If I understand your code correctly, really all you're trying to do is loop for each element in your array. In C#, the number of elements within an array is stored within the "Length" property. You could do something like this, then:
for(int i = 0; i < minX.Length; i++)
...
You could do it using sizeof, as you've already discovered, but I don't think there's a way around doing that without marking the code as unsafe.
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John, thanks for the reply. I was wondering if I could just use mnX.Length myself. It definitely seems more elegant.
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I am wanting to know what is the best way to fill a combo box from data in a database. Right now I am using an data adapter to fill a dataset that is set as the datasource for the combo box. This seams to work ok.
From reading about datasets and dataadapter it looks to me that using this method keeps the link to the database open. Is that true?
On another combo box I have in my program I use a dataset to read an xml file. Then I use a foreach loop to add the data to the combobox. It is a small list of 10 or so records. The only problem with this is that I haven't found a way to add a value to each item in the combo box.
Using the dataset I can set the display member and value member. Just wanted to know what everyone though about this.
I am also concerned about how much memory is taken up by the comboboxes and the datasets that fill them.
Please let me know what you think about this. I know it is a small thing I want to make sure I'm using the best method.
Thanks,
JefferyS 
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I almost always use a dataset for the for the combo box. I would imagine that most others here would agree that there is nothing wrong with using datasets for combo boxes.
Jefferys wrote:
From reading about datasets and dataadapter it looks to me that using this method keeps the link to the database open. Is that true?
If you are using the Fill method of a dataAdapter to fill your dataset, then you are usually in a disconnected state. The Adapter connects to the database for the query, and then disconnects when it is finished. If you are using a dbConnection object, and opening/closing the connection yourself, then it's possible that you might be leaving the connection open. Either way, it is safer to let the dataAdapter do the work for you.
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I have a listcontrol in report mode, and I want the text in a particular column to be right aligned. That is, I want to see the end all the time. I cannot find a way to do this, I thought I had, but all I am aligning is the header. Is there a way to align the contents of the column, or do I need to draw the column myself ? Can I draw just one column ?
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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I usually just use the designer to set up my list controls and setup column/header properties (title, alignment, and size) at that time. I've never yet had an instance in the programs I've developed where I didn't know how I wanted data aligned/formatted at design time.
Now, one thing I've noticed in general about list controls is that it doesn't seem you can right-align the FIRST column in a list control, but I believe that's a global truth about list controls, and not something specific to WinForms.
If at all possible, I would really recommend doing it through the designer. If it's not possible, I'd still recommend doing one through the designer and then look at the code that is generated and compare it with what you're doing. If you can't figure it out still, post some code that can be commented upon.
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Thanks for your advise. I've moved the column along from the first position, and set it up in the designer to be right aligned, all this does is right align the header ( which didn't happen even when I started ).
I'm adding the columns in the designer, and there's a drop down list for text alignment, which I set to 'Right'. This generates the same code I tried to add, something like thelist.Columns.TextAlignment = HorizontalTextAlignment.Right.
Thanks for your help.
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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If you add Items at design-time (for testing purposes only) through the "Items" collection (you'll have to add SubItems of the first item, just the way list controls work), do these show up right aligned? They do for me when I setup a sample list control through the designer, add columns, and add items. If they show up left aligned, even for fields that you know are right aligned, you've got bigger problems and someone else will have to pipe in with some thoughts (possibly bad COMCTL32???)...
If, then, you run your program, only to see everything left aligned, it's pretty obvious that something else is either resetting or recreating the properties on your control. Expand out all the regions of your code and just search for anything related to your list control, paying special heed to anything that may be happening more than once. If you can't isolate it, in the worst case scenario, you can always delete the object off your form/control, and keep re-compiling/fixing errors until you're sure all the code related to the control is gone, then re-add it. I'm sure someone else has other ideas but these are just the ones I can think of.
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Thanks - I did all that, and I get a list where the header text is right aligned, but the text in the actual column is not. I am using XP Pro, FWIW. It looks exactly the same as if I play with the code. I added an item, and added subitems until I got to the right column, made that one really long, and I can read the left portion of it, instead of the right.
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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Ooops, I misunderstood the original post, when I add really long lines, I experience the same behavior you do. I think what you're looking for is definitely possible, but this functionality isn't even available in the Win32 list control (to my knowledge). About the closest thing you could do with the standard control is to add tooltips.
Other than that, I think your only choice is making your own custom list control.
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Yeah, that's what I figured. Thanks for helping me to clarify the point. I guess I'll write such a control towards the end of the project if I find the time. It's my idea, not a specced requirement
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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This makes no sense to me. You appear to be talking about a business domain and assuming everyone already knows it already.
jdemaria wrote:
But I want it to show an actuall dollar value instead of just incrementing like a normal counter
The code you have given appears to have nothing to do with the user interface. What do you mean by "show"?
I'm having difficulty parsing the word "like". Do you mean "like" meaning "similar to" or "like" as a filler word that is otherwise insignificant?
jdemaria wrote:
This is the standard increment how do I just give it my calculated value?
What is "value" unless it is calculated from somewhere. Calculated from what? Where does value come from anyway?
Sorry, you'll have to be more explicit in your request.
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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Your right and I have figured it out anyway. Thank you.
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Can anyone help me create a Dental database system for recording patients records, I need help.
I have created the tables using Access, and want to link them to visual studio using a .SQL server, it doesnt have to be anything fancy just a start.
If you can help then email me at email2miles@yahoo.com
Or reply on here.
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Miles Roberts wrote:
Can anyone help me create a Dental database system for recording patients records, I need help.
In short, no, however if you have a specific question in doing so, absolutely. No one on here will do your work for you, however we would all love to help if you are stuck on something specific. There are plenty of articles on CP that cover how to interact with a database, look through the articles and read MSDN[^] as well.
- Nick Parker
My Blog | My Articles
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Miles Roberts wrote:
I have created the tables using Access, and want to link them to visual studio using a .SQL server
These are two different database technologies. Which do you want to use Access or SQL Server?
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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yea i have designed the access part, and i think i have just linked it so i can view the tables etc in the server explorer, but this was using jet 4.0 provider.
YOu think i am alright using that?
Now i wanna design some forms and get some queries running, any advice?
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Miles Roberts wrote:
YOu think i am alright using that?
I don't know that depends on what you are trying to achieve. Access is good as a desktop database with a limited number of users. SQL Server is good at being a server database with many users. Access has lots of built in functionality to allow whole applications to be built with it. SQL Server provides functionality that supports its use in a n-tier environment. If you are not using the application side of the Access database, MSDE may be a better choice as it is a cut down version of SQL Server that supports a limited number of users, but integrated just like the full SQL Server. You can also create Stored Procedures with SQL Server which mean that you get an extra layer of protection as your application interacts with the Stored Procedure rather than directly with the tables.
Miles Roberts wrote:
Now i wanna design some forms and get some queries running, any advice?
I am assuming you mean Windows.Forms rather than the forms in Access. However I don't know what you are looking for in advice - the design aspect is entirely dependent on what you need to achieve.
You should think about the types of things that need to be recorded at certain stages of the service (e.g. when a patient arrives for an appointment, when the dentist requests a follow-up appointment, the patient calls to cancel/rearrange an appointment). This is where Use Cases come in handy. If you don't want to go to the formality of Use Cases then you can just think of lots stories where an interaction with the system occurs, where does information come from, who interacts with the system you are building, what are the outputs (e.g. Is it just an update in the database, or is an invoice printed or whatever). Once you have these stories you can begin to see what forms you will need to design and what to put on them. Some stories may overlap somewhat and you might be able to design a form that fits into two or more stories.
Does this help? If not, you may need to be more detailed in what you are trying to achieve.
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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Yes i mean windows.forms, i have a scenario written out and want a way to record details of the patient etc and tell him/her when there next appointment will be. I dont want it to print, however if i have time i can introduce an appointment card.
Firstly i bought the wrox press beginning c# databases book and that loads an employee database up which you can run queries select etc.
I need to know how i can do that using my dentist access database, so i can design forms and select different patient records and add new patients in.
Its difficult to explain, should i send you my access database first?
Miles
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Some questions:
1. Is this your first ever C# program ?
2. Is this your first ever database program ?
3. Is this your homework ?
As has been said, Access and SQL Server are two different things. SQL Server obviously canes Access, but if you're only doing something simple, Access has some benefits, some of which can be achieved with MSDE. For starters, if this is not homework, and if someone is actually going to use this code, do they have a licence for SQL Server ?
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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No this is not my first c# program
first database though
yes its for university. but i only need some advice.
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OK, well, a DataGrid provides out of the box Excel like editing for a data source, and with articles on this site you can add drop down lists that reference lists in your data. As has been said, Access and SQL Server are two very different beasts. If it's for a computing degree, I recommend using SQL Server, seeing as it is useful in the 'real world'. Apart from that, you'll need to be more specific. What does your database schema look like ? What information do you need to store in it ?
Christian
I have drunk the cool-aid and found it wan and bitter. - Chris Maunder
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Miles Roberts wrote:
Can anyone help me create a Dental database system for recording patients records
Pay me and I can do it for !  ;);P 
"Creating tomorrow's LEGACY systems today.....
.... One CRISIS at a time!" -- Unknown
"If you build it....
.....BUGS will come!" -JB
this.Dispose();
"A Bug is a piece of code that knows whatz itz purpose" - I Dunnnnooooooo
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i have a problem some parts of the image of the form still on the screen after i close the form which affect the form under it
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