Re: _ID field goes wrong - C# Discussion Boards

Re: Cross Threads problemo (invalidoperationexception)

Quake2Player22-Jun-09 8:36

22-Jun-09 8:36

Sorry to revive this thread but I have a question:

If I have my model separated from the UI, lets say they are two projects,

If the model is the one running the different threads instead of the UI.. (and the model raises events) then I wouldnt have this problem of crossing threads and the Invoke solution?

Or I would have it either way?

_ID field goes wrong

misCafe22-May-09 15:28

misCafe

22-May-09 15:28

I have coded to retrieve data from SQL Server to ListView on C Sharp.
Unfortunately, ID field goes wrong. Obviously, it has four records then it display on a listview with double recode. See my codes ....

dbConnection.sqlCnn.Open();
string sSQL = "SELECT * FROM TBL_USER";
SqlCommand sCommand = new SqlCommand(sSQL, dbConnection.sqlCnn);
SqlDataReader sReader = sCommand.ExecuteReader();

while (sReader.Read() == true)
{
_ID.Add(sReader[0].ToString());

for (int i = 0; i < _ID.Count; i++)
//for (int i = 0; i < sReader.FieldCount; i++ )
{
lstItems = new ListViewItem((i + 1).ToString());
lstItems.SubItems.Add(sReader[1].ToString());
lstItems.SubItems.Add(sReader[2].ToString());
lstItems.SubItems.Add(sReader[3].ToString());
lstItems.SubItems.Add(sReader[4].ToString());
lstItems.SubItems.Add(sReader[5].ToString());
this.lsv_user.Items.Add(lstItems);
}
}
sReader.Close();
dbConnection.sqlCnn.Close();

Thanks

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

Re: _ID field goes wrong

Luc Pattyn22-May-09 16:13

Luc Pattyn

22-May-09 16:13

Hi,

your code does not make sense to me.
the while loop iterates over the records, that is OK.
the for loop should not be there: IMO each record only provides data for one item in the ListView.

Smile | :)

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Re: _ID field goes wrong

misCafe22-May-09 16:43

misCafe

22-May-09 16:43

Well, I have commented on //for (int i = 0; i < sReader.FieldCount; i++ ) so, it isn't used.
Exactly, if we do a right code, it will display a correct recode (only four records on listview). In db it has only four records. After I have coded (code i have posted), it displays many records (duplicate records) on the listview. One record in db it shows many records on listview.

Do you make sense? Smile | :)

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

Re: _ID field goes wrong

fly90422-May-09 17:10

fly904

22-May-09 17:10

misCafe wrote:
Do you make sense?

Yes he does, you on the other hand don't.

It seems that you are confussing 'records' and 'fields', records are the rows in the database and fields are the columns. The code that you have provided shows that you are adding the same row for every field (column) you have. sReader is the record (row), sReader[i] is the field (column). Hence why you go through the DataReader record by record (sReader.ReadLine()), and for each record you then go through it field by field, as shown in my other post.

I hope that clears things up.

My failometer is detecting vast quantities of FAIL!

"Its SQL - hardly programming..." (Caslen)

Re: _ID field goes wrong

Luc Pattyn22-May-09 17:18

Luc Pattyn

22-May-09 17:18

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Re: _ID field goes wrong

Luc Pattyn22-May-09 17:19

Luc Pattyn

22-May-09 17:19

you have two for loops, only one of them is commented out.

Smile | :)

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Re: _ID field goes wrong

fly90422-May-09 16:34

fly904

22-May-09 16:34

misCafe wrote:
while (sReader.Read() == true)
{
_ID.Add(sReader[0].ToString());

for (int i = 0; i < _ID.Count; i++)
//for (int i = 0; i < sReader.FieldCount; i++ )
{
lstItems = new ListViewItem((i + 1).ToString());
lstItems.SubItems.Add(sReader[1].ToString());
lstItems.SubItems.Add(sReader[2].ToString());
lstItems.SubItems.Add(sReader[3].ToString());
lstItems.SubItems.Add(sReader[4].ToString());
lstItems.SubItems.Add(sReader[5].ToString());
this.lsv_user.Items.Add(lstItems);
}
}

With that, you are adding the same record to the ListView n(sReader.FieldCount) times. Your problem is the line in bold, you are adding the same ID/name ((i + 1).ToString()) for each record. Each ListViewItem should have a different name or be blank (no parameter).

I think I know what you are trying to do, so I hope this helps:

if (sReader.FieldCount > 0)
{
    _ID.Add(sReader[0].ToString());
    lstItems = new ListViewItem(sReader[0].ToString()); //Notice: If this is your ID column then it should be unique each record.
    for (int i = 1; i < sReader.FieldCount; i++)
    {
        lstItems.SubItems.Add(sReader[i].ToString());
    }
    this.lsv_user.Items.Add(lstItems);
}

You just need to replace the content of your while loop.

My failometer is detecting vast quantities of FAIL!

"Its SQL - hardly programming..." (Caslen)

Re: _ID field goes wrong

misCafe22-May-09 17:27

misCafe

22-May-09 17:27

Thank you very much again.

I understand what you said and it is solved now.

Smile | :)

Chuon Visoth
Angkor Wat - Cambodia
asp.net - c sharp beginner

windows installer user interface checkbox to disable next button

Member 202095122-May-09 11:07

Member 2020951

22-May-09 11:07

hi guys,
in the setup project i added checkboxes dialog to user interface section. i have two checkboxes to install two products accordingly.
if the user unchecks the both of the checkboxes, i want the next button to be disabled.
do you know how to do that?
thanks

Change FileAccess/FileShare permissions on a FileStream

Dan Neely22-May-09 10:18

Dan Neely

22-May-09 10:18

Is there anyway to do this without closing/reopening the file?

I found this in some code I wrote a few years, and after cringing and hitting google, failed to do so.

m_fsXMLLib = new FileStream(m_fileName, FileMode.Create, FileAccess.ReadWrite, FileShare.None);
// stuff that writes to the file



//there doesn't appear to be any way to change FileAccess values while the stream is open,
//and the risk of a steal occuring here is much lower than a read attempt in midwrite.
m_fsXMLLib.Close();
m_fsXMLLib = new FileStream(m_fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.Read);

My intent is to keep anyone from trying to read the file while it's being written and in an inconsistent state. After saving the file, I want it kept open to prevent anyone else from being able to modify it while letting them have read only rights.

It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains.
-- Pride and Prejudice and Zombies

Re: Change FileAccess/FileShare permissions on a FileStream

Luc Pattyn22-May-09 11:21

Luc Pattyn

22-May-09 11:21

Hi Dan,

interesting question.

IMO a pure .NET solution does not exist. This is what I would try:
- create the FileStream with Share.None
- write and flush the data
- now P/Invoke to CreateFile, specify Share.Read and a zero FileMode (which .NET compiles but refuses to run) as explicitly allowed here[^]
- finally close the original FileStream.

That may run all right and yield a file readable for others.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

Re: Change FileAccess/FileShare permissions on a FileStream

Dan Neely22-May-09 15:52

Dan Neely

22-May-09 15:52

Thanks, I'll give it a shot when I get back into the office on tuesday.

It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains.
-- Pride and Prejudice and Zombies

How to get the roles for a user other than the current one

MGoetz22-May-09 8:22

MGoetz

22-May-09 8:22

I am writing a web application that I want to use windows authentication for. The only problem is that the users using it may not always be running it from there own machine. I want to check the roles for the current windows user and if they have the required role take them directly into the application. If the current user does not have the required role I will take them to a sign-on page so they can enter their windows user i.d. and password. Then I will check if that user has the required role. The problem is that I can only find a way to check the roles for the current windows user.

Is there a way to validate the user that signs in to the application rather than the windows user and check the roles or groups they are in?

Thank you
Marty

Re: How to get the roles for a user other than the current one

0x3c022-May-09 8:48

0x3c0

22-May-09 8:48

Use the techniques from this article to impersonate the user given their username and password. Create a new System.Security.Principle.WindowsIdentity object from the token you'll get back from LogonUser. Use my code from this post, where currentPrinciple is the WindowsIdentity you created

Re: How to get the roles for a user other than the current one

MGoetz22-May-09 9:13

MGoetz

22-May-09 9:13

Thank you, I will try this as soon as possible.

Marty

Re: How to get the roles for a user other than the current one

MGoetz26-May-09 4:44

MGoetz

26-May-09 4:44

Thank you this helped greatly.

Marty

external database?

benjamin yap22-May-09 6:55

benjamin yap

22-May-09 6:55

Hi, i want to create an application that can be loaded into anyone computer.. But the database has to be consistent, so i was thinking of using my web server mysql database.

but how do i use the database from the application i created?

Re: external database?

EliottA22-May-09 7:06

EliottA

22-May-09 7:06

Use a webservice to communicate with the database and have some sort of authentication system for your client.

Check out the CodeProject forum Guidelines[^]

Re: external database?

benjamin yap22-May-09 7:09

benjamin yap

22-May-09 7:09

can give me some idea of what web service?

Re: external database?