C# Discussion Boards - CodeProject

Moreno Airoldi3-Jun-09 0:40

3-Jun-09 0:40

You are using an SqlConnection, which is specifically for SQL Server.

Try to use an OleDbConnection and you should be all right. Smile | :)

2+2=5 for very large amounts of 2
(always loved that one hehe!)

The_Collector3-Jun-09 4:00

The_Collector

3-Jun-09 4:00

yes, thank you but my problem is the connection string that i can be use to connect to Sybase(Adaptive Server Anywhere 6.0)... most of the examples in the net use access database..... can u give me the right connection string for the above server?...

xxx

Moreno Airoldi3-Jun-09 5:21

3-Jun-09 5:21

Sorry I have no experience with Sybase, so I cannot help you with connection strings.

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Exception when making a control button

The_Collector3-Jun-09 14:36

The_Collector

3-Jun-09 14:36

thax anyway......

xxx

gwithey3-Jun-09 0:08

gwithey

3-Jun-09 0:08

I am trying to make a button to represent a volume control knob such as on a CD player in c#

The following error has croped up and i cant find any "Useful" information on what could be wrong.

Does anyone know how to resolve this Exception:

"WindowsFormsControlLibrary1.dll' doesn't contain any UserControl types."

Why would the namespace not contain a user control or could i have not linked the dll properly?

Thanx

Re: Exception when making a control button

Moreno Airoldi3-Jun-09 0:21

Re: Exception when making a control button

3-Jun-09 0:21

I guess you get this error when you try to run your solution (F5) inside Visual Studio.

You cannot directly run a dll, you should set up an executable project in your solution and make it the "Startup Project" for the solution.

For example, create a new Windows Form executable and link your dll in it, in order to test your custom button.

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Rob Philpott3-Jun-09 0:21

Rob Philpott

3-Jun-09 0:21

I've never seen such an exception before so have been looking around. Some people who've had this problem were trying to start the wrong project in the solution. Could this be it?

Don't understand that though, as if you try to start a .dll Visual Studio tells you not to be so stupid, and not with those words.

Regards,
Rob Philpott.

Re: Exception when making a control button

gwithey3-Jun-09 0:56

gwithey

3-Jun-09 0:56

Thanx for the help.

I was thinking along those lines just before you posted.
I made a new project and linked to the user control i had creted to it, my button didnt do what it was meant to (due to my coding abitlity) although it did compile.

I think it may be because i had a form in the user command project to show its asthetics, and tried to run it on that which did not work.

may need to start a new thread on the functionality now thought.

Solved thanx for helping.

How to encapsulate C++ in C#

sbotz2-Jun-09 23:55

sbotz

2-Jun-09 23:55

Hi !

I am looking for a tool to automatically encapsulate C++ library into C#.

I found some tutorials which tell me to first encapsulate classes in C++/CLI and then I could invoke my managed c++ classes into my C# project. But that's a lot of dummy work! I think automatics tools exist but I can't find them D'Oh! | :doh:

Any suggestions ?

Thanks.

Simon P Stevens3-Jun-09 1:02

Simon P Stevens

3-Jun-09 1:02

You can use Tlbimp[^] to automatically create a CLR assembly with the appropriate metadata for a COM type.

Simon

sbotz3-Jun-09 1:20

sbotz

3-Jun-09 1:20

I found this tool, but it works only if your library is COM. That's not my case. Frown | :(

Do you know how to create automatically COM interfaces for my C++ library? So I can use tlbimp !
Create COM interfaces with my little hands is as uncomfortable as creating C++/CLI wrappers, I have more than 300 classes !

Simon P Stevens3-Jun-09 3:16

Simon P Stevens

3-Jun-09 3:16

Sorry, I don't.

I think Visual studio can help, but it's not something I've ever used.
http://msdn.microsoft.com/en-us/magazine/cc301337.aspx[^]

Simon

Dave Kreskowiak3-Jun-09 3:24

Dave Kreskowiak

3-Jun-09 3:24

sbotz wrote:
Do you know how to create automatically COM interfaces for my C++ library?

You can't. The library has to be specifically written to be exposed through COM.

There is no tool to automatically import a C library into a C# app. You have to write the extern references, defining the functions your importing and their parameters and passing methods, yourself. You'll need the documentation on that library because there is no way to determine what the expected parameters and their types are.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

cross thread events

spiritboy2-Jun-09 23:55

spiritboy

2-Jun-09 23:55

i have posted almost the same question earlier, but this one is more straitforward:

i want to handle events that raise by thread1 and process them with thread2, that's all!

or

i want to command thread2 to do sth from thread1

Re: cross thread events

Moreno Airoldi3-Jun-09 0:15

Problem with multiple versions of references

3-Jun-09 0:15

I had a look at your original post, and I think it will make it easier for you if you change your design a bit.

If I uderstand correctly, you want to show your main form, and then show a splash screen right on top of it with a progress bar showing the advancement of some intialization work carried out by a background thread.

Try this way:

- Use the standard Main() for a Windows Form application, which will just run the app showing the main form (Form1).

- In the Shown() event handler for Form1, show the splash screen (Form2), create your thread, link its events to functions in Form2 and start the thread.

- When you get an event from the thread, use Invoke() to update the progress bar. As others told you, this is the best way to do that.

- If you feel unsure about Invoke(), set up a thread-safe (using lock) property in Form2 and update it from the events handlers, then have a timer check it and update your progress bar. This is not good design, but it will work.

I hope I got your problem correctly, and hope this can help you. Smile | :)

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Re: cross thread events

harold aptroot3-Jun-09 0:22

harold aptroot

3-Jun-09 0:22

This would be a producer-consumer problem[^] it's really common so I'm sure there are lots of articles about it on CP.
Often implemented with a non-binary semaphore and a queue (or 2 semaphores and a circular buffer)

Re: cross thread events

S. Senthil Kumar3-Jun-09 9:12

S. Senthil Kumar

3-Jun-09 9:12

If thread2 is a UI thread, all you need to do is call Invoke/BeginInvoke on one of the controls created on that thread. Otherwise, the typical way is to share a queue between the two threads, and have the second thread watch the queue and process commands as they come in.

Regards
Senthil [MVP - Visual C#]
_____________________________
My Home Page |My Blog | My Articles | My Flickr | WinMacro

vijaylumar2-Jun-09 23:47

vijaylumar

2-Jun-09 23:47

hi
my project is like this..
basing on the inputs given by user, i should generate a Drawing in Autocad
my problem is ...
client has so many Autocad versions
example: Autocad 2004,2005 ,2006,2007,2008,2009

and his requirement is like this ..
if the Current active Document belongs to Autocad 2006 then the drawing should be generated in that version apllication

what the client is saying is ..
suppose he opens Autocad 2006 application and runs the project then the drawing should be generated in Autocad 2006 application only

please help me
thanks in advance
vijay kumar d

mysql connect + retrieving record

benjamin yap2-Jun-09 23:40

benjamin yap

2-Jun-09 23:40

Hi, i am using mysql connector for my C# project.

I want to retrieve all the values from the database where username = "testing"

Database.cs

public MySqlDataReader getAccountDetails(String username)<br />
{<br />
    Connect();<br />
    command = conn.CreateCommand();<br />
    command.CommandText = "Select * from accounts where admin_num  ='" + username + "'";<br />
    reader = command.ExecuteReader();<br />
    Close();<br />
    return reader;<br />
}

frmMain.cs

private void frmMain_Load(object sender, EventArgs e)<br />
{<br />
    toolStripDateLabel.Text = DateTime.Now.ToString();<br />
    db.Connect();<br />
    MySqlDataReader reader = db.getAccountDetails(username.ToString());<br />
    <br />
    while (reader.Read())<br />
    {<br />
        string thisrow = "";<br />
        for (int i = 0; i < reader.FieldCount; i++)<br />
            thisrow += reader.GetValue(i).ToString() + ",";<br />
        listBox1.Items.Add(thisrow);<br />
    }<br />
    db.Close();<br />
}<br />

it gives me an error "Invalid attempt to Read when reader is closed."

Blue_Boy2-Jun-09 23:52

Blue_Boy

2-Jun-09 23:52

Did you try to search on google by your error message?[^]

I Love T-SQL
"Don't torture yourself,let the life to do it for you."
If my post helps you kindly save my time by voting my post.

Moreno Airoldi2-Jun-09 23:58

2-Jun-09 23:58

benjamin yap wrote:
public MySqlDataReader getAccountDetails(String username)
{
Connect();
command = conn.CreateCommand();
command.CommandText = "Select * from accounts where admin_num ='" + username + "'";
reader = command.ExecuteReader();
Close();
return reader;
}

You close the database connection after running ExecuteReader(), that's your problem. When you close the connection, the associated reader is closed too. Smile | :)

2+2=5 for very large amounts of 2
(always loved that one hehe!)

benjamin yap3-Jun-09 0:01

benjamin yap

3-Jun-09 0:01

thannks!!! solved :DDDD