Entity Framework: Create new Object (when relation exists) - C# Discussion Boards

12-Jul-09 10:08

Am I just crazy or is it kind of hard to find a sample on using WIA with a digital camera.. I also read something that you might not be able to do this with Vista?

I got my camera to take a picture...

Item pic;
ImageFile myImg;

pic = _Device.ExecuteCommand(CommandID.wiaCommandTakePicture);
myImg = (ImageFile)_Device.Items[0].Transfer(FormatID.wiaFormatJPEG);


PictureBox picBox = new PictureBox();
picBox.Dock = DockStyle.Fill;
picBox.Image = (Image)myImg.FileData;
this.Controls.Add(picBox);

But on trying to Transfer I get:

Exception from HRESULT: 0x8021006B

Jacob Dixon12-Jul-09 14:45

12-Jul-09 14:45

Sorry I meant I'm getting a NullReferenceException.

Jacob Dixon12-Jul-09 15:28

12-Jul-09 15:28

Whatever I do it always returned null!

Sean Devoy26-Aug-09 14:44

Sean Devoy

26-Aug-09 14:44

I realize this is a little old, but maybe this will help others. My code is in VB but does not take much to convert to C#.

In XP this code takes and saves a picture:

item = dev.ExecuteCommand(CommandID.wiaCommandTakePicture)
Dim myImage As WIA.ImageFile = CType(item.Transfer(format), WIA.ImageFile)
myImage.SaveFile("c:\somewhere\mypicture.jpg")

But in Vista "item" is ALWAYS NULL but it does take the picture on the camera.

here is my fix:

' get current image count
Dim cnt As Int32 = dev.Items.Count

'take picture
 item = dev.ExecuteCommand(CommandID.wiaCommandTakePicture)

 ' insert this single if block
 If IsNothing(item) Then
   ' Vista drops the ball here (and a lot of other places!)
   '  Loop for up to 10 seconds waiting for the image to appear on camera device
    While dev.Items.Count = cnt And x < 10
       System.Threading.Thread.Sleep(1000)
       x+= 1
    End While
    If cnt = dev.Items.Count Then
         'throw your exception here - no image arrived
    Else
         ' we found the new image on the camera
         ' pull it into the "item" variable since Vista didnt
         item = dev.GetItem(dev.Items(cnt - 1).ItemID)
    End If
End If
' and the rest of the code is unchanged.

Hope that helps.

Jacob Dixon26-Aug-09 15:12

Improve Speed of send message from server to all Clients

26-Aug-09 15:12

You know I got it to work with WIA1 but never the version WIA2.
Thats because I used WIA1 on XP and WIA2 on Vista.

I see what you are saying. I was always able to get the camera to take a picture, but it never assigned the picture to the item.
I see what you did. You just take the amount of pictures on the camera, make it snap a picture, then if item is null (which is always will be) loop for 10 seconds OR until the count changes on the camera. Then get the last picture.

Genius! I'll give it a try

Vu Nam Son12-Jul-09 7:34

Vu Nam Son

12-Jul-09 7:34

I write new application server/client. I use TcpClient. When my server is listening and allow many computers connect. Example : My server have 50 computers client connected. I have problem when I want to send 1 message to all clients, I must use FOR/NEXT therefore It cost 5 seconds or more to send 1 message to 50 Computers client. Now I want to improve speed of send message, Please give me advice.

Please see code below

//Send Admin Message
public static void sendAdminMessage(string sMessage)
{

//ArrayList LIST_CLIENT contain all connections of client
if (LIST_CLIENT.Count > 0)
{
Object []arr = LIST_CLIENT.ToArray();
for (int i = 0; i < arr.Length; i++)
{
try
{
MyClient client = (MyClient)arr[i];
send(client.TcpClient, sMessage);
}
catch(Exception e) {
Console.WriteLine(e.Message);
}
}
}
}

Re: Improve Speed of send message from server to all Clients

Christian Graus12-Jul-09 7:36

Christian Graus

12-Jul-09 7:36

If you have the bandwidth, you could send each message on a seperate thread.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Re: Improve Speed of send message from server to all Clients

Behrooz_cs12-Jul-09 9:27

Behrooz_cs

12-Jul-09 9:27

you should use 2 threads for each client + 1 thread for entire network.
thread1)its priority should be low till they get a message from application in their line(collection for messages, you should build a class for that).
when message(s) got finished the priority should be set to low
thread2)should always read streams and add them to the line class associated with it.

net thread) should read lines of messages gotten by second set of threads and execute them.

i have did it and it worked very well.
i had a project i named it remotecompiler the project sends codes objects events procedures gets services from clients or server such as NetService FileService... (i used IServiceProvider class) and can execute orders with its services (it had about 50 classes)
i think tis may get you a good idea.
please tell me when you done it

How can I intercept audio output?

blametom12-Jul-09 7:01

12-Jul-09 7:01

How can I intercept the audio output as it goes to the sound card? is there an audio stream that I can access using .net or third party library?

I'm trying to write a program for correcting lip sync problems when playing back blu-ray discs. I'm hoping to be able to intercept the audio output from the computer and then add an adjustable time delay before sending it back to the audio output again.

Is this possible?

Cheers

Christian Graus12-Jul-09 7:35

Christian Graus

12-Jul-09 7:35

I would imagine you're going to play with DirectX to intercept the audio stream and introduce a delay. I don't know exactly how you'd do that, tho

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Richard Andrew x6412-Jul-09 17:32

Richard Andrew x64

12-Jul-09 17:32

Google this name, "Total Recorder".

They sell a library that lets you intercept the audio stream.

However, it doesn't work with Vista because Vista has a protected audio stream.

blametom13-Jul-09 6:19

13-Jul-09 6:19

Richard Andrew x64 wrote:
Google this name, "Total Recorder".

They sell a library that lets you intercept the audio stream.

However, it doesn't work with Vista because Vista has a protected audio stream.

Thanks, I've had a look at Total Recorder, the latest version does work with vista athough it seems that all I can do with it is duplicate the audio stream as it is output rather than being able to actually reroute it. I might be wrong of course.

What I would really like to be able to do is capture the audio stream before it gets to the sound output device and then add my delay before sending it on again.

blametom13-Jul-09 8:27

13-Jul-09 8:27

I have come accros another issue whist trying to use directx to acheive my goal. I thought I would start by attempting to identify what the sound output device was identified as so I wrote the following to hopefuly display all my sound devices.

DevicesCollection devList = new DevicesCollection();

foreach (DeviceInformation device in devList)
{
    Console.WriteLine(device.ToString());
}

Unfortunately running this code reulted in the following error.

LoaderLock was Detected
DLL 'C:\Windows\assembly\GAC\Microsoft.DirectX\1.0.2902.0__31bf3856ad364e35\Microsoft.DirectX.dll'
is attempting managed execution inside OS Loader lock. Do not attempt to run managed code inside a
DllMain or image initialization function since doing so can cause the application to hang.

I've never come accross this before and have absolutely no idea how to resolve it. I'm a bit of a beginner having completed only 1 year of a computer science degree course so far and errors like this just tend to floor me. Confused | :confused:

blametom14-Jul-09 2:26