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Re: How can I control sampling rate from C#, i.e of times I read a variable in a sec

Luc Pattyn10-Mar-10 16:27

10-Mar-10 16:27

Three ways in C#:

1. you can use a timer to get an event at some rather low frequency (well below 1 kHz); it wouldn't be very reliable, there would be some jitter (you might want to read my timers article).

2. you can choose a realtime thread priority, and cause a busy loop to monopolize one CPU core to read a parallel pin at high frequency (hundreds of kHz); the exact frequency would depend on the number of instructions in your loop and your CPU frequency.

3. you can provide an external clock, then choose a realtime thread priority, and cause a busy loop to monopolize one CPU core to read a parallel pin at high frequency (hundreds of kHz). By waiting on the external clock, your code would be independent of the exact instructions and your CPU frequency.

Other ways would include writing a specialized driver (not in C# though).

None of the above is likely to be acceptable as far as behavior and results quality go. If you want to create say an oscilloscope, you need more external hardware, including some memory, so the communication doesn't have to be real-time at all.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

How C# should communicate with access db file ?

biscoito10-Mar-10 13:04

biscoito

10-Mar-10 13:04

Well, I have a lot of questions regarding this topic, so i'll show you some of my doubts:

I'm currently developing a C# windows forms application that communicates with a access database file to store all my data. Now that my relational database is getting bigger, i'm wondering if I should make table relations inside the access file or in C#. Sometimes I have to make changes to more than one table at a time and I don´t know how and who should do these kind of transactions (access/c#). I need to use DataSets, Datareaders, Databinding, etc to do that, right? How these communication should work, I mean, best practice for this!?

Hope you can help me with this.
Thanks, bisc8

PS - Some good book about this?

Re: How C# should communicate with access db file ?

Not Active10-Mar-10 15:17

Not Active

10-Mar-10 15:17

The database is the proper place to define the data structure. I would also suggest using SQL Express rather than Access. If your needing to scale it will provide better capabilities than Access.

biscoito wrote:
I need to use DataSets, Datareaders, Databinding, etc to do that, right?

What do DataSets or DataReaders have to do with defining the structure of a database? I think you are very confused.

I know the language. I've read a book. - _Madmatt

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 16:17

coding freaks

10-Mar-10 16:17

SQL Express compact edition is the best db that can go with C#. Are u developing in C#.net or ordinary c#?

Re: How C# should communicate with access db file ?

Luc Pattyn10-Mar-10 16:29

Luc Pattyn

10-Mar-10 16:29

sidhu hacks wrote:
C#.net or ordinary c#?

Feel free to explain that.
AFAIK there is VB and VB.NET; however I've never seen any C# outside a .NET environment.

Confused | :confused:

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

Re: How C# should communicate with access db file ?

Not Active10-Mar-10 16:38

Not Active

10-Mar-10 16:38

sidhu hacks wrote:
SQL Express compact edition is the best db that can go with C#.

Care to explain that? You mean SQL Server or Oracle can't be used with C#? I think you are very misinformed.

I know the language. I've read a book. - _Madmatt

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 16:42

coding freaks

10-Mar-10 16:42

i didnt mean that this is the only db that can go with c#. I meant its best to use rather than access or any other.(bcoz i feel easy in this compact edition Poke tongue | ;-P

)

Re: How C# should communicate with access db file ?

Not Active10-Mar-10 16:46

Not Active

10-Mar-10 16:46

Wrong again. Perhaps you should research a little, http://www.microsoft.com/sqlserver/2008/en/us/editions.aspx[^] The best database is the one that fits the needs

I know the language. I've read a book. - _Madmatt

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 16:52

coding freaks

10-Mar-10 16:52

did u read the content within those bracket?

Re: How C# should communicate with access db file ?

Not Active10-Mar-10 16:57

Not Active

10-Mar-10 16:57

I've done more reading than you apparently. What is your point? Just because you are more comfortable with one database or edition over another does not make it the "best" choice.

I know the language. I've read a book. - _Madmatt

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 16:59

coding freaks

10-Mar-10 16:59

best choice for me yar... i didnt say for all... ok u want in access? right? i wil send u via mail...

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 17:17

coding freaks

10-Mar-10 17:17

hi biscoito ur mail id pls. i wil mail u the porgram from which i learnt. its i access...

Re: How C# should communicate with access db file ?

Not Active10-Mar-10 17:30

Not Active

10-Mar-10 17:30

1) you should be responding to the op
2) the op is a fool if they take advice or examples from you since you can't even respond to the correct post and don't know what c# is or which database edition to choose let alone the other posts you have made

I know the language. I've read a book. - _Madmatt

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 19:58

coding freaks

10-Mar-10 19:58

i just said i'm confortable with it man.. thats all dont start scolding me..

Re: How C# should communicate with access db file ?

Dave Kreskowiak10-Mar-10 17:56

Dave Kreskowiak

10-Mar-10 17:56

Noone in their right mind is going to give you their email address.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 20:01

coding freaks

10-Mar-10 20:01

how should i take it as?
A compliment?

Re: How C# should communicate with access db file ?

Dave Kreskowiak10-Mar-10 17:42

Dave Kreskowiak

10-Mar-10 17:42

sidhu hacks wrote:
best choice for me yar

Are you the one that's going to be running the code? Storing the information? No. Your application requirements dictate the database you use, NOT your confort level with it.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 20:02

coding freaks

10-Mar-10 20:02

since he asked for db connection i thoguht he s a noob like me.. and so i told him wat i felt thats all.... chill out...

Re: How C# should communicate with access db file ?

Luc Pattyn10-Mar-10 17:34

Luc Pattyn

10-Mar-10 17:34

you've got a new fan! Laugh | :laugh:

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

Re: How C# should communicate with access db file ?

coding freaks10-Mar-10 20:17

coding freaks

10-Mar-10 20:17

required

using System.Data.OleDb;

Declaration part Smile | :)

string id;
string sqlQRY;
OleDbConnection cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "/Data.mdb");
OleDbCommand cmd = new OleDbCommand();
OleDbDataReader dr;

Open the connection in this statement

cn.Open();

its like database items loading in a list

cmd.CommandText = "SELECT * FROM tbladmin ORDER BY ID ASC";
cmd.Connection = cn;
dr = cmd.ExecuteReader();
while (dr.Read())
{
ListViewItem list = new ListViewItem(dr[0].ToString());
list.SubItems.Add(dr[1].ToString());
list.SubItems.Add(dr[2].ToString());
listView1.Items.AddRange(new ListViewItem[] { list });
}
dr.Close();

this is wat i can help for now.. it tedious cant post the whole code here.. sending ur mail id wil help....
others pls gimme a break .. stop pulling my leg...

Text Files

Darrall10-Mar-10 12:55

Darrall

10-Mar-10 12:55

I have added a Text File to my project. Can somebody please tell me what the code is to send, modify and retrieve information - say from text boxes - to that file?

Re: Text Files

DaveyM6910-Mar-10 14:16

DaveyM69

10-Mar-10 14:16

Have a look at the TextReader, TextWriter and File classes all in the System.IO namespace. They contain everything you need.

Dave

Binging is like googling, it just feels dirtier. (Pete O'Hanlon)

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

Re: Text Files

Darrall10-Mar-10 14:36

Darrall

10-Mar-10 14:36

Thanks

Looping through Dataset instead of DataGridView?

Eagle3210-Mar-10 11:48

Eagle32

10-Mar-10 11:48

Hi,

I would like to loop through the DataSet at runtime to retrieve selected values and store them in local variables but i am not sure how i could do this using DataSet that is generated using the inbuilt wizard. I am using SQL Server Compact. My database has "*.sdf" extension. I created a strongly typed DataSet using the wizard. So in the solution explorer i can see the DataSet and it has an extension of "*.xsd".

At the moment i am doing this:

foreach(DataGridViewRow dgvrow in CustomerGridView.Rows)
{
  //e.g to get surname
  String Surname = dgvrow.Cells[2].Value.ToString();
  //do some other stuff here too

}

Wouldnt it be more efficient if i looped through the DataSet that I have created? If so, how would i go about doing this based on the above code.

If anybody could assist me with this, it would be much appreciated.

Thanks,

Re: Looping through Dataset instead of DataGridView?

Dan Mos10-Mar-10 12:03

Dan Mos

10-Mar-10 12:03

use something like:

ds.TableName[RowIndex].ColumnName;

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.