Best way of Data Sync - C# Discussion Boards

Re: Deleting nodes recursivily

4-Jan-07 1:46

One way to do this would be to recurse to the bottom nodes and then delete from the bottom up. The pseudo logic would look like this:

function LoopItem(Node parentNode)
{
  for each Node childNode in parentNode
  {
    LoopItem(childNode)
    childNode.Delete
  }
  parentNode.Delete
}

All you would need to do then, is to call LoopItem with the parent node.

the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer

Deja View - the feeling that you've seen this post before.

Gareth H4-Jan-07 2:56

Gareth H

4-Jan-07 2:56

Cheers, it seems the key to why my code wasnt working was i was deleting the node then looping, instead of looping and then deleting.

Regards,
Gareth.

DataGridView that searches like outlook

robmays3-Jan-07 23:50

robmays

3-Jan-07 23:50

Does the datagridview in vs2005 work like outlook. ie I know it works the same when you click the column headings but in outlook you can move to rows in that column by pressing say 's' to move the record selector to the beginning of all the 'S' in the column you have just ordered by. if it does how do you active that functionality. If not is there one can buy that will do the same?

Re: DataGridView that searches like outlook

Nader Elshehabi4-Jan-07 0:30

Re: DataGridView that searches like outlook

4-Jan-07 0:30

robmays wrote:
If not is there one can buy that will do the same?

Wow! You go for the cash pretty quickly!! Smile | :)

Even though DataGridView doesn't support this feature natively, you can make it by two simple steps:
1- Change the DataGridView.EditMode to EditOnEnter for example -ie. Anything that doesn't include KeyStroke-.
2- Handle the DataGridView.KeyPress event -or any other key event-, and put the code that goes through the rows -using a foreach loop- to check your desired column if it starts with the specific key the user entered.

PS.
You can add the feature of supporting two-or three strokes search -like the windows explorer. ie. searching for "sam" not just "s"-, by storing the keystrokes in a temp string and clear that string after a small timer elapse to start over a new search if the user presses a key.

Regards

robmays4-Jan-07 0:36

robmays

4-Jan-07 0:36

excellent ,dont like to spend money. can you give me some simple c# code to steer me in the right direction? that you would use in the events.

Re: DataGridView that searches like outlook

Nader Elshehabi4-Jan-07 1:40

4-Jan-07 1:40

Ummm.... Did you notice point number 2 in my previous post? What is it that's not clear about it?

Regards

Best way of Data Sync

fearless stallion3-Jan-07 23:46

3-Jan-07 23:46

Hi,

I am bulding a simple windows application. the forms read data from the database and show it. the user can modify the data through the forms and the data is updated. it works fine as long as it is used by single user on a single machine.

But I want this to be used by different users on the network. There may be an instance where two or more users can open the same form. So any changes made to a record by one user can not be reflected on the other end Frown | :(

but i want changes to be reflected on all machines where the same form is opened.

How can i achieve this Confused | :confused:

? Please suggest me a way ?

thanks in advance

kss

Nader Elshehabi4-Jan-07 0:22

4-Jan-07 0:22

fearless stallion wrote:
the forms read data from the database and show it

What data provider you use? Whether you use Oracle, Sql Server, Db2, etc... It's the responsibility of that Database engine to synchronize the data read/write access. For sure there won't be any write errors, yet if you didn't update your data in the form, it could be inaccurate as it has been updated by another user. So from time to time you should refresh your display based on something -e.g. timer, events, messages, etc...-.

Regards

fearless stallion4-Jan-07 1:59

4-Jan-07 1:59

Hi,

Thanks for the reply, I think , what i have written earlier is a little confusing. I am using MySql provider. and there is no problem with MySql provider. But what i want is:

for eaxmple: if Two users "Chris" and "Sally" open the same form. suppose Chris Modifies the record no.13 and the record is updated to database but Sally's screen still shows the Old data. I can refresh the whole screen by re-fetching the data from the DB but is time consuming.

but i want some other solution may be an network event kind, whenever change occurs in other machine. it(machine) sends a message kind to all the peers(who have the same form opened). so that i can manage it on the frontend itself. as the data is huge so it is not possible for me to refresh again and again.

How far this is possible ?

thanks again

kss

Nader Elshehabi4-Jan-07 3:36

4-Jan-07 3:36

Well. Here is how I do it
1- Put the database on the server. -intuitive, isn't it?- Smile | :)

2- Put a Windows Application -or service-, or Webservice according to either your program is on LAN/Internet respectively, as a gate to that database.
3- All requests are directed to that "Gate" program through remoting
4- All programs record there interest on the current displayed record and the gate keeps track of that
5- if a record is displayed on one client and another modifies it the gate notifies the interested clients using messages.
6- Messages and requests are preferably routed using Remoting.

This is one way to do it. Does this help?

Regards

fearless stallion4-Jan-07 20:44

4-Jan-07 20:44

Well I Have never worked on Remoting and if this will help me then i Would not mind Working. I will look into this , if you have any good links of this kind of implementation then can please let me know, it will be of great help

Thanks again

kss

Nader Elshehabi4-Jan-07 21:54

4-Jan-07 21:54

fearless stallion wrote:
if you have any good links of this kind of implementation

If you mean remoting, try this link[^]. It'll get you started in no time.

Regards

Pete O'Hanlon4-Jan-07 1:59

4-Jan-07 1:59

If the database is Sql Server 2005, you could always use SQL Server Notifications to notify clients that an event has happened. It would be the responsibility of the client to retrieve/work out what the changes are.

This is not a task for the faint hearted and I am currently writing a set of articles on how to use Notifications.

fearless stallion4-Jan-07 2:01

4-Jan-07 2:01

Thanks but I using MySQL 5.0.

kss

Pete O'Hanlon4-Jan-07 2:35

4-Jan-07 2:35

You could roll your own version. It wouldn't be trivial, but would work like this:

Have your application poll a notifications table at a regular interval.
Whenever a record is inserted/updated/deleted that you are interested in, update the notifications table.
If there is a record there that you are interested in (probably identified via a timestamp) refresh your application

fearless stallion4-Jan-07 3:04

4-Jan-07 3:04

Can MessageQueue be used in this Context ?

kss

Pete O'Hanlon4-Jan-07 3:49

4-Jan-07 3:49

Probably not. Well, you could use it but it doesn't bring you any benefits.

datatable

fmardani3-Jan-07 23:44

fmardani

3-Jan-07 23:44

Several combo boxes on the UI winform are populated using a DataTable. ie. dtUsers
dtUsers is a table in a dataset.
Several combo boxes are populated using this datatable.

Not sure why when an item in one of the combo boxes is selected, then all the other combo boxes get changed too.

This is a sample of how the combo boxes are populated:

dtUsers = dsUsers.Tables["Users"];
cbo1.DataSource = dtUsers;
cbo1.DisplayMember = "Name";
cbo1.ValueMember = "UserID";

Re: datatable

robmays3-Jan-07 23:54

robmays

3-Jan-07 23:54

I have had the same problem and solved it by using different datasources and not binding all combo boxes to the same datasource. So change this line dtUsers = dsUsers.Tables["Users"];
to another source

Re: datatable [modified]

Nader Elshehabi4-Jan-07 0:49

How to add a form in a dockpanel

4-Jan-07 0:49

I assume of course that in cbo2 you give the DisplayMember a different value, right? Try to make a break point to see if this value applies or not.
Anyway, I've been working with ADO .Net and databindings for quite a while now, and let me tell you I'm completely displeased with it. It has many bugs, and what would Microsoft would call "features" that costed me a lot of time to discover it. When I submitted somehting to them all they said was "Make your own workaround. We don't have the time to fix this in the next version of Visual Studio. Thank you!", and that's it.
Anyway. A good way -that works for me- is to use a BindingSource and bind it to your controls using cbo1.DataBindings.Add() method. It works fine fr the Text property -but not with CheckBox.Checked property BTW-. A sample would be

BindingSource UsersSource = new BindingSource();
UsersSource.DataSource = dsUsers.Tables["Users"];
cbo1.DataBindings.Add(new Binding("SelectedItem", UsersSource, "Name"));
cbo1.DataBindings.Add(new Binding("SelectedValue", UsersSource, "UseID"));

I hope it works for you! Smile | :)

-- modified at 6:55 Thursday 4th January, 2007

The above code I use for a DropDownList combobox. You can also bind to the Text property according to your need.

Regards

GunaChinna3-Jan-07 22:51

GunaChinna

3-Jan-07 22:51

Hi there,
Can you please tell me, how can i add a form in a dockpanel in c# 2005.

Re: How to add a form in a dockpanel

Pete O'Hanlon3-Jan-07 23:16