Re: select from a datatable - C# Discussion Boards

Re: Microsoft Code Blocks?

27-Sep-06 5:03

Hello

Click here.[^]

Regards

Judah Gabriel Himango27-Sep-06 6:06

Judah Gabriel Himango

27-Sep-06 6:06

Whoa! It's all in sanscript/Arabic, and it's right-to-left! Smile | :)

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Re: Microsoft Code Blocks?

Michael P Butler27-Sep-06 6:30

Michael P Butler

27-Sep-06 6:30

kumar.bs wrote:
Can anybody tell me something about Microsoft Code Blocks?

Do you mean application blocks[^]?

What do you want to know?

As the site says

Application Blocks are reusable source-code components that provide proven solutions to common development challenges. They can be integrated as is into applications, or they can be extended or customized. patterns & practices Application Blocks address specific recurring problem domains such as data access, logging, user interface process, and composite user interfaces.

Michael

CP Blog [^] Development Blog [^]

select from a datatable

playout27-Sep-06 4:26

27-Sep-06 4:26

Hi,

I am trying to run a select query on a datatable.
The datatable holds information I get from an Access database.

My code:

<br />
            OleDbConnection myConn = new OleDbConnection();<br />
            myConn.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;data source=" + DBPath;<br />
<br />
            OleDbCommand myCommand = new OleDbCommand();<br />
            myCommand.Connection = myConn;<br />
            myCommand.CommandText = "Select * from [tblMembers] where Active = false";<br />
            myCommand.CommandType = System.Data.CommandType.Text;<br />
            System.Data.DataTable myTable = new System.Data.DataTable("myTable");<br />
<br />
            OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myCommand);<br />
            myDataAdapter.Fill(myTable);

I have to query three columns in the datatable (MemberID, MemberLanguage, MemberName), and bind those info to the following variables:

intMemberID, strMemberLanguage, strMemberName

How can I do this?

Nader Elshehabi27-Sep-06 4:37

27-Sep-06 4:37

Hello

You can do that using OleDbCommand.ExecuteReader() that will return a DataReader object. Using it you can get your results.
About the columns selection, then you sould modify your SELECT statement. Binding them to these three variables is quite unclear. Data binding is done with bindable controls, not variables.

Regards

Not Active27-Sep-06 4:53

27-Sep-06 4:53

Nothing wrong with using the DataTable he has. The DataReader is a connected object which may not be optimal for the situation.

only two letters away from being an asset

playout27-Sep-06 19:53

27-Sep-06 19:53

Nader Elshehabi wrote:
You can do that using OleDbCommand.ExecuteReader() that will return a DataReader object. Using it you can get your results.
About the columns selection, then you sould modify your SELECT statement. Binding them to these three variables is quite unclear. Data binding is done with bindable controls, not variables.

This is not really what I wanted, I already have the info in the datatable, I just need to query it, using some sort of select statement, where I can select the current row that has the values I need, and bind those values to variables.

Not Active27-Sep-06 4:51

27-Sep-06 4:51

intMemberID = Convert.ToInt32(myTable.Row[0]["MemberID"]); ...

only two letters away from being an asset

Nader Elshehabi27-Sep-06 4:59

27-Sep-06 4:59

I'd be extremely surprised if that's what he was asking about?!! I had all sorts of guesses jumping in my mind of what really he was asking about. A guy who makes an SqlConnection didn't know how to convert a string to Int32?!! WTF | :WTF:

Regards

playout27-Sep-06 19:51

27-Sep-06 19:51

Nader Elshehabi wrote:
I'd be extremely surprised if that's what he was asking about?!! I had all sorts of guesses jumping in my mind of what really he was asking about. A guy who makes an SqlConnection didn't know how to convert a string to Int32?!!

I am not sure if you were talking of my message, but what I meant was. I have a datatable, already filled with information from the database. Now I need to use some of the data in that datatable, bind to a variable I can use throughout my application. I am building the app as a windows app.

The problem is, I have a MemberID(it's unique and primary key), that I need to use to get the member's language and name from the datatable. So I wanted to do something like

SELECT MemberID, MemberLanguage, MemberName FROM "mytable" where MemberID = strCurrentMemberID<br />
'mytable = the datatable

I dont know how to do this select from a datatable.

Not Active28-Sep-06 2:09

28-Sep-06 2:09

playout wrote:
SELECT MemberID, MemberLanguage, MemberName FROM "mytable" where MemberID = strCurrentMemberID
'mytable = the datatable

That should do it

only two letters away from being an asset

playout27-Sep-06 19:56

27-Sep-06 19:56

Thanks, this might be helpful, only problem is, I dont know what row the value is in, so how can I search via row?

EG: The member details for the current row can be in row 5 or 68 for that matter, the only reference I have, is an employee number.

Not Active28-Sep-06 2:11

Re: Access metod from thread

28-Sep-06 2:11

Given your scenario and my understanding of it, if you have more that one record returned then you have something wrong in your database.

only two letters away from being an asset

Access metod from thread

Neuromancer_27-Sep-06 4:20

Neuromancer_

27-Sep-06 4:20

Please help! How can i access metod UpdateRows from another thread in this code?
Thanks.

using ...

namespace pddServer
{
public partial class Form1 : Form
{
public class ThreadedTcpServer
{
public void StartServer()
{
ConnectionThread newconnection = new ConnectionThread();
Thread newthread = new Thread(new ThreadStart(newconnection.HadnleConnection));

newthread.Start();
}

class ConnectionThread
{
public void HadnleConnection()
{
connections++;

//
// How can i call method UpdateRows from this place?
//
connections--;
}
}
}

private Thread ServerThread;

public Form1()
{
InitializeComponent();

ThreadedTcpServer Server = new ThreadedTcpServer();
ServerThread = new Thread(new ThreadStart(Server.StartServer));
ServerThread.Start();
}

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
ServerThread.Abort();
}

public void UpdateRows()
{
dataGridView1.Rows.Add();
}
}
}

Nader Elshehabi27-Sep-06 4:34

Here's a free db connection object for all!! Any improvement ideas?

27-Sep-06 4:34

Hello

Your multithreading module is not right IMO. Your thread must be an object in your From class, not in a separate class. Then it should know about the UpdateRows method's existence and call it using this.Invoke().

Regards

Goalie3527-Sep-06 3:49

Goalie35

27-Sep-06 3:49

Ok, I created a sql server database connection object for all to use if you're interested however I'm posting this on here with the hopes that people try to make improvements upon it and can share their changes with me. I've only been coding in C# for a little while now so I'm hoping for some advice on where I can make improvements.

Currently, it's only compatible with SQL Server & requires a stored procedure and it then reads a connection string stored in either the web.config or app.config file.

It can return data as a datatable or dataset or return nothing at all. Each method can accept up to 10 arguments to be passed into a stored procedure. If a user needs to declare more than 10 arguments, they must pass them in as an array.

So for those who don't know, a sample web.config file would be setup like this (although I recomend encrypting your config file if you use this on a server):
------------------------------------------------------------------
<configuration>
<appSettings/>
<connectionStrings>
<add name="SqlServerConnection"
connectionString="Data Source = yourDataSource;Initial Catalog = dbName;User Id =yourUserId;Password = yourPWord;"
providerName="System.Data.SqlClient"/>
</connectionStrings>
-------------------------------------------------------------------

You can then create an instance of the DBConn object like the following:
----------------------------------------------------------------------
DBConn dbConnection = new DBConn("SqlServerConnection");
DataTable dtTable = dbConnection.PopulateDataTable("storedProcName", argument1);
----------------------------------------------------------------------

The file can be located at http://www.jennyperl.com/stuff/DBConn.zip

I'd greatly appreciate any advice/additions that can be made to this to help improve upon it. If you simply wish to use it as is and make no improvements, I hope it helps make your coding a little easier.

If you wish to contact me personally, you can email me at goalie35_33@yahoo.com.

Thanks.

-Goalie35

Re: Here's a free db connection object for all!! Any improvement ideas?

Colin Angus Mackay27-Sep-06 5:41

Colin Angus Mackay

27-Sep-06 5:41

Goalie35 wrote:
although I recomend encrypting your config file if you use this on a server

I strongly recommend using Windows Authentication to access your SQL Server so you don't have to store usernames and passwords in plaintext files.

Goalie35 wrote:
Each method can accept up to 10 arguments to be passed into a stored procedure. If a user needs to declare more than 10 arguments, they must pass them in as an array.

Why not just use the params keyword then you won't have to have this limit. You can pass in as many as you like - Internally, within the method, you would still treat them as an array, but you wouldn't need to do that to call the method.

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Re: Here's a free db connection object for all!! Any improvement ideas?

Michael P Butler27-Sep-06 6:33

Michael P Butler

27-Sep-06 6:33

Goalie35 wrote:
I'd greatly appreciate any advice/additions that can be made to this to help improve upon it. If you simply wish to use it as is and make no improvements, I hope it helps make your coding a little easier.

Have a look at the Data Access Application Block[^] in the Enterprise library.

Michael

CP Blog [^] Development Blog [^]

Programmatically grouping taskbar buttons

Wjousts27-Sep-06 3:40

Wjousts

27-Sep-06 3:40

Does anybody know if it is possible to write a program that will force the taskbar buttons associated with a certain program (a different one) to group? The problem I have is that a program written in LabVIEW by an outside contractor insists of having two taskbar buttons although one is basically a dummy for the LabVIEW runtime engine. The contractor says that there is no way to fix this from LabVIEW. I was wondering if it would be possible to write a small C# program to act as a loader for the LabVIEW program, force it's icons to group and then quit.
I found this article as a start, but it doesn't suggest a way to force buttons to group.

Thanks

Ed.Poore27-Sep-06 4:19

Ed.Poore

27-Sep-06 4:19

Not sure if it'd work but how about using the C# "loader" program to have the ShowInTaskbar property of the main form set to false? I don't think this will work because if you simply execute the program (I.e. you can't link into it) then it will display it's icon.

There may be an API for this but as I hate WinXPs guts I have no idea on how to do this Cool | :cool:

Wjousts27-Sep-06 5:10

Wjousts

27-Sep-06 5:10

Ed.Poore wrote:
Not sure if it'd work but how about using the C# "loader" program to have the ShowInTaskbar property of the main form set to false?

Interesting, I didn't think of that. I'll have to give it a try and see what happens. Cheers.

Ed.Poore27-Sep-06 5:20

Ed.Poore

27-Sep-06 5:20

Depends on how you load the program, I'm pretty sure if you just the shell to execute it then it won't work.

Wjousts27-Sep-06 6:16

Wjousts

27-Sep-06 6:16

Ed.Poore wrote:
I'm pretty sure if you just the shell to execute it then it won't work.

Yes, I am just using the shell to execute. From the Process class I can get the handle of the main window, but now I need to figure out if there is a way to use that to stop it from displaying a taskbar button.