C# Discussion Boards - CodeProject

goldoche5-Jul-07 5:47

5-Jul-07 5:47

Hi, I have a ComboBox to which I give a string array as a DataSource. It works. I also have a DataSet and one of the columns of a table contains the SelectedIndex of this ComboBox, but when I bind it, it does not select the right index.

I've decided to bind it to a numericUpDown and it works, so what's going on with the comboBox?

Here's my code:

// The numeric updown displays "3", which is good!<br />
numericUpDown1.DataBindings.Add("Value", dataset.LoadModule, "RampUpSpeed");<br />
<br />
// The selected index of the comboBox is 0, which is not good!<br />
rampUpCombo.DataBindings.Add("SelectedIndex", dataset.LoadModule, "RampUpSpeed");

Thanks!

Using code behind to retreive ms access data

markymark825-Jul-07 5:05

markymark82

5-Jul-07 5:05

hey all,

I'm tring to pull records from an access database in my c#.net web app.

Doing it using VS2005 in the gui view is fine but I want to set up a connection server side and pull records using a reader like I would with sql, however, I can't seem to find the syntax. I have created the connection string but from there on it seems quite a bit different from an sqlconnection.

I'm after the equivilant of below:

//------
OleDbConnection dbConnect = new OleDbConnection(@"Dsn=MS Access Database;dbq=C:\Program Files\Sage\Accounts\DBFile.mdb;defaultdir=C:\Program Files\Sage\Accounts;driverid=25;fil=MS Access;maxbuffersize=2048;pagetimeout=5;uid=manager");

OleDbCommand dbcommandCom = new OleDbCommand(@"select * from [invoice]");

dbConnect.Open();

OleDbDataReader RecReader = null;

dbConnect.Open();

RecReader.Read();

dbConnect.Close();
//-----------

Can someone please help as I have a short timescale for the project.

Thanks in advance
mark

Re: Using code behind to retreive ms access data

Christian Graus5-Jul-07 5:21

Christian Graus

5-Jul-07 5:21

Basically, I believe you call Read over and over, and each time you do, the reader points to the next record, and you can access the columns of that row before calling read again.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Using code behind to retreive ms access data

Guffa5-Jul-07 6:23

Guffa

5-Jul-07 6:23

It looks like you create a connection object, a command object and a reference for a data reader, and hope that they will automatically find each other, execute the command, create a data reader object and place in your reference. They don't. You have to make the command object use the connection, then you have to use a method in the command object like ExecuteReader to execute the command, and assign it's return value to your reference. Then you can start to read from it.

Look at any examples out there. They are everywhere.

markymark82 wrote:
I have created the connection string but from there on it seems quite a bit different from an sqlconnection.

On the contrary. From there on the code is very similar.

---
single minded; short sighted; long gone;

Re: Using code behind to retreive ms access data

markymark825-Jul-07 9:46

markymark82

5-Jul-07 9:46

ok,
so should I actually be using the 'OleDbConnection', as currently I keep getting errors about the provider for it, the only suggestion i've found is 'provider=sqloledb;' in the connection string, but obviously its not an sql db so that doesn't work, what would the equivilant be for an ms access db?

Otherwise the only other connection object I have found that does not error is:
'AccessDataSource db = new AccessDataSource(@"Dsn=MS Access Database;dbq=C:\Program Files\Sage\Accounts\ODBC.mdb;defaultdir=C:\Program Files\Sage\Accounts;driverid=25;fil=MS Access;maxbuffersize=2048;pagetimeout=5;uid=manager", @"select * from Invoice");'

but from there I have no idea how to open a reader as I can't find an option for it and I can't see how to read the records that are returned from it?

thanks for you help so far, much appreciated

mark

Re: Using code behind to retreive ms access data

Guffa5-Jul-07 11:09

Guffa

5-Jul-07 11:09

Open the properties for the connection that you are using in Visual Studio. There you will see the provider and connection string.

Otherwise connectionstrings.com[^] is good for connectionstrings.

OleDb is the preferred provider for Access.

---
single minded; short sighted; long gone;

Re: Using code behind to retreive ms access data

markymark825-Jul-07 11:14

markymark82

5-Jul-07 11:14

Thanks for the help,

I really appreciate it.

I shall try that outbut for now I have found a way slightly around the problem.
I have created a system odbc object that links to the .mdb file and then linked to it through odbcconnection. This has worked fine for now but I'll still try doing it the other way as i wont have to create odbc objects on each machine its to be installed on.

thanks again

mark

send/recieve email + ping to pc in netwerk using a pocket pc

faladrim5-Jul-07 4:21

faladrim

5-Jul-07 4:21

hi,

i've made an app on my pc who pings to see who's in my network and is able to send emails
i want to do the same on a pocket pc, but i cant seem to find how this works
i get stuck on the fackt that pocket pc in vs 2005 doesn't have :
using System.Net.NetworkInformation;
using System.Web.Mail;
does anybody know were i can find examples or how i send emails or ping ???
plz help! Sniff | :^)

grz muk

Retrieve Installation Path

terrible835-Jul-07 4:09

terrible83

5-Jul-07 4:09

Hi,
i've created a setup project and it works fine. Now i want to retrieve the installation path because i need to set it as current directory for the windows service i've created. How can i do it?
I need to pass through windows registry (how?) or exists a variable or a property which i can read?

Thank you all!

Gianluca

Re: Retrieve Installation Path

originSH5-Jul-07 4:13

originSH

5-Jul-07 4:13

[TARGETDIR] is the property which contains the installation directory.

You can add registry keys via the installer.

Re: Retrieve Installation Path

led mike5-Jul-07 4:39

led mike

5-Jul-07 4:39

terrible83 wrote:
because i need to set it as current directory for the windows service i've created

As someone pointed out in the past few days, best practice is to use absolute paths.

To obtain the path you can access the installation path using the Windows Installer SDK in your service, that is what you are asking correct? However AFAIK this should work:

System.Reflection.Assembly.GetExecutingAssembly().Location

how to insert data

csanda15-Jul-07 3:59

csanda1

5-Jul-07 3:59

Hi
Im doing an application in Visual C# 2005, my application can read data from my database but cant save into the database. Heres the code. What am I missing....Pliz Help!!!!

private void btnSave_Click(object sender, EventArgs e)
{
string strConnection = "Provider=Microsoft.Jet.OLEDB.4.0;"+"Data Source=YAC.mdb";
OleDbConnection conn = new OleDbConnection(strConnection);
conn.Open();
string strCommand = "INSERT INTO ClientProfile(Name,Surname,Gender,IdNumber) Values ('" + txtName.Text + "','" + txtSurname.Text + "','" + cbxGender.Text + "','" + txtIdNumber.Text + "')";

OleDbDataAdapter adapter = new OleDbDataAdapter();
adapter.InsertCommand = new OleDbCommand(strCommand, conn);
(this.yACDataSet.ClientProfile);

int t1 = adapter.InsertCommand.ExecuteNonQuery();
conn.Close();

if (t1 > 0)
{
MessageBox.Show("added successfully!");

}

csanda

Re: how to insert data

led mike5-Jul-07 4:42

led mike

5-Jul-07 4:42

Welcome to CodeProject. There are a large number of C# Database Articles here follow the link[^]

Registry Problems NullException

StevenWalsh5-Jul-07 3:47

StevenWalsh

5-Jul-07 3:47

I'm trying to query the registry on a remote server to verify a value. using the code

<br />
RegistryKey RemoteKey;<br />
                                         string RemoteComputer = LabName + "isp0001";<br />
                                         RemoteKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, RemoteComputer);<br />
                                         string value = RemoteKey.OpenSubKey("SOFTWARE\\Twrap\\Packages\\Completed", RegistryKeyPermissionCheck.ReadSubTree).GetValue("1.3", 0).ToString();<br />
<br />

When i run it i see this:

A first chance exception of type 'System.NullReferenceException' occurred in LabMonitor.exe
A first chance exception of type 'System.NullReferenceException' occurred in LabMonitor.exe

and the exception message is: "Object reference not set to an instance of an object"

Please help Smile | :)

Re: Registry Problems NullException

Christian Graus5-Jul-07 3:55

Christian Graus

5-Jul-07 3:55

StevenWalsh wrote:
and the exception message is: "Object reference not set to an instance of an object"

You're bound to get that when you chain together calls without first checking the return values. I'd assume that OpenSubKey is failing, but you should step through and check it yourself, and write more defensive code in future.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Registry Problems NullException

NassosReyzidis5-Jul-07 3:56

NassosReyzidis

5-Jul-07 3:56

Hello Steven,
either the RemoteKey is null or
the "RemoteKey.OpenSubKey("SOFTWARE\\Twrap\\Packages\\Completed", RegistryKeyPermissionCheck.ReadSubTree)" is null

change your code from:

RegistryKey RemoteKey;<br />
string RemoteComputer = LabName + "isp0001";<br />
RemoteKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, RemoteComputer);<br />
string value = RemoteKey.OpenSubKey("SOFTWARE\\Twrap\\Packages\\Completed", RegistryKeyPermissionCheck.ReadSubTree).GetValue("1.3", 0).ToString();

to:

RegistryKey RemoteKey;<br />
RegistryKey RemoteSubKey;<br />
string value;<br />
string RemoteComputer = LabName + "isp0001";<br />
RemoteKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, RemoteComputer);<br />
if (RemoteKey != null)<br />
{<br />
     RemoteSubKey = RemoteKey.OpenSubKey("SOFTWARE\\Twrap\\Packages\\Completed",RegistryKeyPermissionCheck.ReadSubTree);<br />
     if (RemoteSubKey != null)<br />
     {<br />
          value = RemoteSubKey.GetValue("1.3", 0).ToString();<br />
     }<br />
}<br />
if (value != null && value.Length>0)<br />
{<br />
   //The SubKey exist do your staff with the value<br />
}

GanDad

Re: Registry Problems NullException

StevenWalsh5-Jul-07 4:09

StevenWalsh

5-Jul-07 4:09

Hi, i've tried your code, and i'm still getting the exception here is where it is stopping

RemoteKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, RemoteComputer);

Re: Registry Problems NullException

Christian Graus5-Jul-07 4:22

Christian Graus

5-Jul-07 4:22

Breaking it down will just help you work out where the problem is. It won't change that you are making a call which is returning null, and not checking it.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Registry Problems NullException

StevenWalsh5-Jul-07 4:42

StevenWalsh

5-Jul-07 4:42

Christian Graus wrote:
Breaking it down will just help you work out where the problem is. It won't change that you are making a call which is returning null, and not checking it.

i broke it down some more and narrowed to problem down to the string "value" i made value an object datatype and it now works.

user id,password.etcc..

myat_035-Jul-07 3:05

myat_03

5-Jul-07 3:05

this is the problem

Create a User class. This class should at least contain the following fields:
User ID
Password
First Name
Last Name
E-mail Address
Status - valid values are 'Inactive', 'Active', 'Deleted'
Define constructors that accept the following parameter lists:
All parameters: User ID, Password, First Name, Last Name, E-mail Address, Status
User ID, Password and E-mail Address
User ID and Password Only
** The status field should be initialized to 'Active' upon creation
** Constructors 2 and 3 should use a constructor initializer

Define read-only properties that return the following:
IsActive – whether or not the account's status is active
FullName – a concatenation of the account's first and last names
Define additional properties that behave as follows:
UserID
Set operation should ensure the user id does not start with a digit and should only update the user id field if the given value is valid
Get operation just returns the user id
Password

pls help me... Cry | :((

just notify me through my email...

......

Re: user id,password.etcc..

originSH5-Jul-07 3:10

originSH

5-Jul-07 3:10

Thats a nice specific specification so just impliment it.

You need only the most basic knowledge of c# to achive this.

Re: user id,password.etcc..

myat_035-Jul-07 3:25

myat_03

5-Jul-07 3:25

i am in a short period of time and i do have problem on my computer..i can't practice now..i find source of this project and i try this site that someone could help me to this problem..

......

Re: user id,password.etcc..

originSH5-Jul-07 3:36

originSH

5-Jul-07 3:36

So because it's got to be handed in soon and you didn't do it in time you want someone else to do it for you?

Re: user id,password.etcc..

Christian Graus5-Jul-07 3:56

Christian Graus

5-Jul-07 3:56

every homework request comes with a sob story. This is really straight forward. If you try to do it yourself and you need help with specific things, that's different, but for you to just post your homework and hope someone will do it is, frankly, kind of rude.

So, I ask again, which specific bits are confusing you ? Do you want to ask some specific questions to help you in approaching this task ?

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: user id,password.etcc..

Christian Graus5-Jul-07 3:19

Christian Graus

5-Jul-07 3:19

Which part of your (pretty simple) homework is confusing you ? This is a basic exercise in OO. We never do homework, but this in particular, is pretty vital for you to understand, and really not hard.

I would guarentee that any text you've been assigned will cover all you need to know to do this.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

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