C# Discussion Boards - CodeProject

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

Problem with multiple versions of references

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

Moreno Airoldi

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

Moreno Airoldi

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

benjamin yap3-Jun-09 0:07

benjamin yap

3-Jun-09 0:07

hmm how do i retrieve the value from the reader

I want to specify the column name instead of the row number

reader.GetValue("username");

something like this

Controlling Navigation in IE using c#

Moreno Airoldi3-Jun-09 0:33

Moreno Airoldi

3-Jun-09 0:33

You can use Reader["ColumnName"] - it will return an object, so you might need to convert it to the specific data type. For example:

double var = 0;
if (Reader["MyField"] != DBNull.Value)
{
  var = Convert.ToDouble(Reader["MyField"]);
}

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

svt gdwl2-Jun-09 23:38

svt gdwl

2-Jun-09 23:38

Open Internet Explorer(IE) with about:blank as its home page
The links which i will traverse are
1.http://www.google.co.in
2.http://www.msn.com/
3.http://www.yahoo.com
Then If I press the BACK button(i.e.,navigation toolbar), http://www.msn.com/ is opened on IE, but instead of http://www.msn.com/ I want the link http://www.google.co.in to be opened. How can I do this in c#?

I mean when we click the back button once, I want the the back button operation sholud be performed twice. How to do this.
(OR)
How can I make the IE to directly traverse from http://www.yahoo.com to http://www.google.co.in in one click of back button?

Re: Controlling Navigation in IE using c#

Pete O'Hanlon2-Jun-09 23:54

Pete O'Hanlon

2-Jun-09 23:54

Why are you trying to do this? In line with your other post earlier on today, it looks like you are trying to implement something for malicious purposes. I, for one, will not help write code that is destined to act in an inappropriate manner.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Copying a file with progress

musefan2-Jun-09 23:31

musefan

2-Jun-09 23:31

Hi all,

Within my application I need the ability to copy a file. The thing is I also want to use a progress bar to show how much of the file is uploaded/total etc.

So this rules out the use of System.IO.File.Copy() - Of course, I know, I will use a stream and write a chuck of data at a time and then report progress in-between each chuck... Yeah, that seems to work great...

PROBLEM: I used this method to copy a Word Document (Office 2007). The copy was fine, but the problem is, when I try to open the document in Word its says something about the file being corrupt, would you like to restore the file? (which succeeds, but is not good enough)

If I use File.Copy() this problem does not happen.

So, question is, how do I create a proper copy of a file while maintaining the ability to notify the user of the progress?

Thanks for any help

Life goes very fast. Tomorrow, today is already yesterday.

Pete O'Hanlon2-Jun-09 23:51

Pete O'Hanlon

2-Jun-09 23:51

You read the file into a byte array using a StreamReader of some description, and write it out using a StreamWriter. Use a BackgroundWorker to run this in, and raise progress changes at appropriate intervals.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

musefan3-Jun-09 0:30

musefan

3-Jun-09 0:30

As I have said I have tried with streams (StreamReader, FileStream and BinaryStream) and this is causing the file to become corrupt - when word tries to open it, it has to restore it.

This does not seem to happen when doing other file types. I can only assume that there is some 'additional info' stored with the file that File.Copy() is capable of handling, but streams are not.

Any thoughts?

Life goes very fast. Tomorrow, today is already yesterday.

Xmen Real 3-Jun-09 0:07

Xmen Real

3-Jun-09 0:07

here is a code snippet that I use

public static void Copy(string sourcePath, string destPath, bool overwrite, int bufferSize, ProgressBar tmp_pb)
{
    if (!overwrite && File.Exists(destPath))
        throw new ArgumentException("File already exists.");

    if (!Directory.Exists(Path.GetDirectoryName(destPath)))
        Directory.CreateDirectory(Path.GetDirectoryName(destPath));

    ////creating non exists directories
    //string[] tmp_destSecs = .Split('\\');
    //for (int a = 1; a <= tmp_destSecs.Length; a++)
    //{
    //    if (!Directory.Exists(string.Join("\\", tmp_destSecs, 0, a)))
    //        Directory.CreateDirectory(string.Join("\\", tmp_destSecs, 0, a));
    //}


    FileStream tmp_fr = new FileStream(sourcePath, FileMode.Open);
    FileStream tmp_fw = new FileStream(destPath, FileMode.Create);

    long fileSize = new FileInfo(sourcePath).Length;
    if (fileSize < bufferSize)
        bufferSize = (int)fileSize;
    long numOfLoops = (fileSize / bufferSize);
    tmp_pb.Step = tmp_pb.Maximum / (int)numOfLoops;
    byte[] tmp_data;
    for (int a = 0; a < numOfLoops; a++)
    {
        tmp_data = new byte[bufferSize];
        tmp_fr.Read(tmp_data, 0, bufferSize);
        tmp_fw.Write(tmp_data, 0, bufferSize);
        tmp_pb.PerformStep();
        Application.DoEvents();
    }
    int leftBytes = (int)(fileSize - tmp_fr.Position);
    if (leftBytes > 0)
    {
        tmp_data = new byte[leftBytes];
        tmp_fr.Read(tmp_data, 0, leftBytes);
        tmp_fw.Write(tmp_data, 0, leftBytes);
    }
    tmp_fr.Close();
    tmp_fw.Flush();
    tmp_fw.Close();
    tmp_pb.Value = 0;
}

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