C# Discussion Boards - CodeProject

Gareth H9-Jun-08 1:04

Gareth H

9-Jun-08 1:04

DeepOceans,

I am not sure if this is correct, but i think its because the thread does the work and then exits, thus the timer will be told to start but then instantly quick, thus it never ticks.

Since i am not sure if my thinking is correct, i dont have a solution other than to keep the thread alive.

Whats the reason you want to run a Timer in the background anyways?

Regards,
Gareth.

(FKA gareth111)

DeepOceans9-Jun-08 1:22

DeepOceans

9-Jun-08 1:22

I m using Timer to enable my function for grabbing the video frames on every tick. yes u might b right that thread does its work and exits but in my case it never actually goes in the function (i checked by printing a messegeBox). i already gave the code. plz try it and tell me more specific reason.
Thanku so much !

Shanzay

#realJSOP9-Jun-08 2:51

9-Jun-08 2:51

Your thread function should look something like this:

private void Thrd1()
{
    // just sit and spin
    while (true)
    {
        // sleep for the desired time - this example uses 1 second
        Thread.Sleep(1000);
        
        Calculate();
    }
}

private void Calculate()
{
    // do some work
}

BTW "Thrd1" is a crappy function name.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

PIEBALDconsult9-Jun-08 5:51

PIEBALDconsult

9-Jun-08 5:51

The Timer uses a thread, so you needn't use your own as well.

#realJSOP9-Jun-08 5:54

9-Jun-08 5:54

But using a thread is more programmerish.

The Timer class is for lazy people.

Smile | :)

PIEBALDconsult9-Jun-08 13:41

PIEBALDconsult

9-Jun-08 13:41

Certainly, but using both at once is nuts.

#realJSOP10-Jun-08 0:11

serialize atextbox control

10-Jun-08 0:11

Agreed.

Elesh8-Jun-08 23:41

Elesh

8-Jun-08 23:41

how to serialize a windows form control (binay or xml serialization) ?

Re: serialize atextbox control

ncjlee9-Jun-08 0:33

ncjlee

9-Jun-08 0:33

[Serializable]
private System.Windows.Forms.Button button1;

at the form.designer.cs code..

modified on Saturday, January 17, 2009 8:11 AM

ListBox throwing a "Not valid value"-exception

Gadjuka8-Jun-08 23:14

Gadjuka

8-Jun-08 23:14

Hi all!

I'm having a problem with checkedlistbox.
At one point I want to update the data associated with the selected item, which is a struct I defined. When I try to do this I get an error:
"Specified argument was out of the range of valid values.Parameter name: '-1'is not a valid value for 'index'"
And then the last item in the list is removed.

CheckedListBoxItem temp = (CheckedListBoxItem)clbFormats.Items[clbFormats.SelectedIndex];
temp.Update = chkUpdate.Checked;
clbFormats.Items[clbFormats.SelectedIndex] = temp;	// <-- This is where it raises an error

The thing is that clbFormats.SelectedIndex isn't -1, it's 0 if I add it to the watch window. And if I do that same with clbFormats.Items[clbFormats.SelectedIndex] it also shows the correct, valid values.
And what's even stranger is that this code works if I compile it in VS2005, unfortunately I have to use VS2003.

/Gadjuka

Re: ListBox throwing a "Not valid value"-exception

#realJSOP9-Jun-08 2:57

Re: ListBox throwing a "Not valid value"-exception

9-Jun-08 2:57

Why don't you just do this:

clbFormats.SetItemChecked(cblFormats.SelectedIndex, chkUpdate.Checked);

Gadjuka9-Jun-08 20:02

Gadjuka

9-Jun-08 20:02

Thanks for the suggestion, unfortunately that won't work.
The CheckedListBox-items and the CheckBox are independent, but for each ListBox-item I need to remember whether the CheckBox was checked when that item was selected.

That's why I need to be able to update the Data associated with each ListBox-item.

Re: ListBox throwing a "Not valid value"-exception

#realJSOP10-Jun-08 0:10

SortedDictionary v.s. Dictionary

10-Jun-08 0:10

I truly dislike wasting my time.

When you ask a question here, clearly state all of your requirements in your original message. Finding the answer you want will require at least 30 minutes. Of course, you're a programmer too (or maybe not), and that's how long it should take YOU to work this out on your own.

George_George8-Jun-08 22:41

George_George

8-Jun-08 22:41

Hello everyone,

Here is my understanding of pros and cons SortedDictionary v.s. Dictionary, am I correct? Or anything important missing? What is your practices of when to use SortedDictionary and when to use Dictionary?

1. Dictionary is faster for insertion and removal, but slower for query value by key compared with SortedDictionary;
2. Dictionary is using a linear array to store key/value pair, but SortedDictionary is using binary search tree to store key/value pair, so for query, SortedDictionary is faster.

thanks in advance,
George

Re: SortedDictionary v.s. Dictionary

leppie9-Jun-08 3:43

leppie

9-Jun-08 3:43

George_George wrote:
1. Dictionary is faster for insertion and removal, but slower for query value by key compared with SortedDictionary;

Lookups should be the same, both O(1).

George_George wrote:
2. Dictionary is using a linear array to store key/value pair,

But this is store in a special order, determined by the hash value of the key. If indeed the SortedDictionay is using a BST, it will be slower for lookups as it will by O(log n).

xacc.ide - now with TabsToSpaces support
IronScheme - 1.0 alpha 4a out now (29 May 2008)

Re: SortedDictionary v.s. Dictionary

George_George9-Jun-08 16:57

George_George

9-Jun-08 16:57

Thanks leppie!

I agree. Looks like lookup operation in Dictionary is faster than SortedDictionary, here are some further documents I found. Do you think they support your conclusion? Smile | :)

Mentioned here,

http://msdn.microsoft.com/en-us/library/xfhwa508(VS.80).aspx

"Retrieving a value by using its key is very fast, close to O(1), because the Dictionary class is implemented as a hash table." Looks like the query time for Dictionary is O(1), but the query time for SortedDictionary is O(logn) -- "The SortedDictionary generic class is a binary search tree with O(log n) retrieval, where n is the number of elements in the dictionary. In this respect, it is similar to the SortedList generic class. The two classes have similar object models, and both have O(log n) retrieval. Where the two classes differ is in memory use and speed of insertion and removal."

http://msdn.microsoft.com/en-us/library/f7fta44c(VS.80).aspx

regards,
George

X509Store from file

komadich8-Jun-08 22:40

komadich

8-Jun-08 22:40

Hello,

It's been a couple of days now that I've been searching for how to instantiate a certificate store FROM A FILE. X509Store class doesen't have any suitable members. Is it possible at all?

Thank you,
komadich

Re: X509Store from file

telha9-Jun-08 0:40

telha

9-Jun-08 0:40

Can you provide some more details that what else you wanna do?

X509Certificate class is used to read a certificate like:
X509Certificate cert = X509Certificate.CreateFromCertFile(PathToCertificate);

If you have a certificate file with extension .cer you can read it's contents through the object of X509Certificate.
MakeCert is a utility with .Net Framework to create a Certificate.
There are other encryption libraries available that you can use to provide a private/public key pair for creating your certificate....?

Whereas the X509Store is used to manage the certificates...

Muhammad Talha

Encoding problem with string from DLL

steve_rm8-Jun-08 21:46

steve_rm

8-Jun-08 21:46

Hello,

VS 2008 3.5.Net

I am getting a string from a call back in a C++ native DLL which I have written. And for some reason it displays wrong something like this. i.e. [][[[[[[[[[[[[[ or ????????????????? with ASCII encoding.

My code is below. I think the DLL is using unicode, and I am trying to encode it in ASCII. The parameter in call back definition is char*. And in my C# I am using a string.

I have also tried Unicode, UTF-8, and ASCII. All of them display incorrectly.

Am I doing something wrong with my code?

Many thanks for any suggestions,

<br />
*.hpp file ==============<br />
typedef int (__stdcall *ptrIncomingCall)(int callID, char *caller);<br />
MOBILEDLL_API int drvIncomingCall(ptrIncomingCall cb);<br />
<br />
*.cpp file ==============<br />
int drvIncomingCall(ptrIncomingCall cb)<br />
{<br />
	int callerID = cb(20, "Joe bloggs");<br />
<br />
	return callerID;<br />
}<br />
<br />
C# code ===============<br />
 private delegate int incomingCallDelegate(int callerID, string caller);<br />
        [DllImport("MobileDLL.dll")]<br />
        static extern int drvIncomingCall(incomingCallDelegate cb);<br />
<br />
        int OnIncomingCall(int callerID, string caller)<br />
        {<br />
            ASCIIEncoding encoding = new ASCIIEncoding();<br />
            byte[] callerBytes = encoding.GetBytes(caller);<br />
<br />
            this.label1.Text = callerID.ToString();<br />
            this.label2.Text = encoding.GetString(callerBytes, 0, callerBytes.Length);<br />
<br />
            return 1;<br />
        }<br />
<br />
        private void button4_Click(object sender, EventArgs e)<br />
        {<br />
            drvIncomingCall((incomingCallDelegate)OnIncomingCall);   <br />
        }<br />

ncjlee8-Jun-08 21:56

ncjlee

8-Jun-08 21:56

private delegate int incomingCallDelegate(int callerID, [MarshalAs(UnmanagedType.LPStr)] string caller);

int OnIncomingCall(int callerID, [MarshalAs(UnmanagedType.LPStr)] string caller)

I think this should work..

steve_rm9-Jun-08 1:45

steve_rm

9-Jun-08 1:45

Hello,

Thanks for your response.

However, I have tried to get that to work. See code below. I am getting a run-time error: "NotSupportException was unhandled" Error No. 0x80131515

Stack Trace:
at MobileApp.Form1.button4_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.ButtonBase.WnProc(WM wm, Int32 wParam, Int32 lParam)
at System.Windows.Forms.Control._InternalWnProc(WM wm, Int32 wParam, Int32 lParam)
at Microsoft.AGL.Forms.EVL.EnterMainLoop(IntPtr hwnMain)
at System.Windows.Forms.Application.Run(Form fm)
at MobileApp.Program.Main()

private delegate int incomingCallDelegate(int callerID,[MarshalAs(UnmanagedType.LPStr)] string caller);<br />
        [DllImport("MobileDLL.dll")]<br />
        static extern int drvIncomingCall(incomingCallDelegate cb);<br />
<br />
        int OnIncomingCall(int callerID,[MarshalAs(UnmanagedType.LPStr)] string caller)<br />
        {<br />
            ASCIIEncoding encoding = new ASCIIEncoding();<br />
            byte[] callerBytes = encoding.GetBytes(caller);<br />
<br />
            this.label1.Text = callerID.ToString();<br />
            this.label2.Text = encoding.GetString(callerBytes, 0, callerBytes.Length);<br />
<br />
            return 1;<br />
        }<br />
<br />
        private void button4_Click(object sender, EventArgs e)<br />
        {<br />
            drvIncomingCall((incomingCallDelegate)OnIncomingCall);   <br />
        }

ncjlee9-Jun-08 2:40

ncjlee

9-Jun-08 2:40

I am not sure why this would happen.
rather than using marshall you could try use StringBuilder instead of string..