Re: Cast where XML file defines what integer and floating point values should be cast to. - C# Discussion Boards

is dataset performs well over Lists when navigating data in the memory

prasadbuddhika8-Jun-09 5:30

8-Jun-09 5:30

i'm trying to develop a data storing component, for it i'm in doubt about using datasets , as i heard datasets are not efficient in memory usage over Lists , is it true

Re: is dataset performs well over Lists when navigating data in the memory

Henry Minute8-Jun-09 9:56

Henry Minute

8-Jun-09 9:56

Do what most people would do.
Develop test routines utilizing each data structure and run them in a loop maybe 1000 times (or more) and time them to find out which works best for your data.

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Web Cam Problem

S K Y8-Jun-09 5:23

S K Y

8-Jun-09 5:23

Hi,
i want to use web cam to capture pictures. to use webcam i have to user avicap32.dll. so how can i add this to reference. i tried by add reference, but couldn't any one please just tell me how can i use avicap32.dll ....
thanks

A S E L A

Re: Web Cam Problem

DaveyM698-Jun-09 5:31

DaveyM69

8-Jun-09 5:31

I believe you need to use pinvoke with that dll.

This article[^] uses it, you may find it of use.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)
Why are you using VB6? Do you hate yourself? (Christian Graus)

Re: Web Cam Problem

Simon P Stevens8-Jun-09 5:38

Simon P Stevens

8-Jun-09 5:38

If the camera supports Windows Image Acquisition (WIA), it's easier to use that. (See here[^])

If it doesn't, then yes acicap32 is an option. (There's a sample here[^])

I believe it would also be possible to do it with direct show, but I think it's probably a bit harder. (see here[^])

Finally there are 3rd party libraries out there that can do things like this. One example is OpenCV[^], and the OpenCVDotNet[^] wrapper.

Simon

How to embed a internet explorer in a webbrowser control using c#

Yukivi8-Jun-09 5:08

Yukivi

8-Jun-09 5:08

Hi, I want to know all the actions that are performed on internet explorer, how can I do these all things?
I want to do these all on client side?

How can I know the information regarding somethings which have been done on web page, For example, things like:
1. How to convert the web page text on fly as there is no onload event
2. How to catch the keyboard actions like keyup, keydown, keypress when something
typed on web page.
3. How to know the information that if something is given to printer, i.e., text that is going to print, from an IE window.

Like these things, I want to get all the things when we perform some action on IE window through a plug-in.

How can I get these all things in c#?
Thank you...

Cast where XML file defines what integer and floating point values should be cast to.

Dennis Lerche8-Jun-09 4:10

Dennis Lerche

8-Jun-09 4:10

Hi

I'm having a problem solving this problem.
I have an XML file describing how the different types (double, float, int and so on) should be interprettet, or how many bits the size of them should be. My application reads the XML and then have to cast for example a double to a float or an int to a short, based on the configuration. Afterward, the new casted or converted value has to converted to a byte array of the size of the type defined in the XML file.

I will just give an example to clarify.

1. Double value received.
2. Convert double value based on the conversion size in XML, double is cast / converted to float.
3. Create byte array from casted / converted value.

I can convert the value without problems using Convert.ChangeType(doubleValue,Type.GetType("System.Single")), but this give an object that I do not know how to make to a byte array of the correct size (32 bits).

Can anyone help me with solving the problem with converting / casting a double to a specific type defined in a XML file and converting this to a byte array ?
What I'm interrested in is the byte array being the size defined in the XML with signed values.

Thanks alot Smile | :)

Dennis

Re: Cast where XML file defines what integer and floating point values should be cast to.

led mike8-Jun-09 5:08

led mike

8-Jun-09 5:08

Dennis Lerche wrote:
converting this to a byte array

Maybe this[^] will work.

Re: Cast where XML file defines what integer and floating point values should be cast to.

Dennis Lerche8-Jun-09 9:52

Dennis Lerche

8-Jun-09 9:52

Yes it works ok, unless you have an object and not a double, float etc.
What I have is an object after performing Convert.ChangeType(doubleValue,Type.GetType("System.Single")), so how do I make this to a byte[] ?

Re: Cast where XML file defines what integer and floating point values should be cast to.

Dennis Lerche8-Jun-09 23:36

Dennis Lerche

8-Jun-09 23:36

The solution I have found is the following:

static byte[] ValueToByteArray(object obj)
{
    int len = Marshal.SizeOf(obj);
    byte[] arr = new byte[len];
    IntPtr ptr = Marshal.AllocHGlobal(len);
    Marshal.StructureToPtr(obj, ptr, true);
    Marshal.Copy(ptr, arr, 0, len);
    Marshal.FreeHGlobal(ptr);
    return arr;
}

This takes any of the int, double etc. types as an object and converts it to a byte[].

How to count a character in a string?

SimpleData8-Jun-09 3:47

SimpleData

8-Jun-09 3:47

Hi I know it's a simple question but I couldn't find it with searching on google.

string a = "asdasd;asdasdasder;asdgfg;ad;;asdasd";

How can I count the number of ;'s in this string?

Thanks.

Re: How to count a character in a string?

PIEBALDconsult8-Jun-09 3:52

PIEBALDconsult

8-Jun-09 3:52

Iterate and count them.

Re: How to count a character in a string?

Blue_Boy8-Jun-09 3:54

Blue_Boy

8-Jun-09 3:54

SimpleData wrote:
I know it's a simple

Yes.

string a = "asdasd;asdasdasder;asdgfg;ad;;asdasd";<br />
<br />
        int charCount = 0;<br />
<br />
        for (int i = 0; i <= a.Length - 1; i++)<br />
        {<br />
            if (a[i].ToString() == ";")<br />
            {<br />
                charCount += 1;<br />
            }<br />
        }

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.

Re: How to count a character in a string?

Luc Pattyn8-Jun-09 4:50

Luc Pattyn

8-Jun-09 4:50

Blue_Boy wrote:
a[i].ToString() == ";"

is a terrible waste

a[i] == ';'

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Re: How to count a character in a string?

Manas Bhardwaj8-Jun-09 3:54

Manas Bhardwaj

8-Jun-09 3:54

int LiCount = 0;
foreach (char Lchar in a.ToCharArray())
{
    if (Lchar == ';')
	LiCount++;
}

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

Re: How to count a character in a string?

SimpleData8-Jun-09 4:10

SimpleData

8-Jun-09 4:10

Hi Thanks you all your answers. I don't know why I couldn't think of this solution. Sometimes I can't think, and this is one of those times I guess. Smile | :)

Re: How to count a character in a string?

Skymir8-Jun-09 4:17

Skymir

8-Jun-09 4:17

int iCount = ("asdasd;asdasdasder;asdgfg;ad;;asdasd".Split(';')).Count<string>() - 1;
Well that gets it down to one line. What's next, obfuscation?

The true man wants two things: danger and play. For that reason he wants woman, as the most dangerous plaything.

Re: How to count a character in a string?

Blue_Boy8-Jun-09 4:26

Blue_Boy

8-Jun-09 4:26

Nice but,instead

Count()

(which is not method) you have to use

Length

int property

int iCount = ("asdasd;asdasdasder;asdgfg;ad;;asdasd".Split(';')).Length- 1;

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.

Re: How to count a character in a string? [modified]

Luc Pattyn8-Jun-09 4:51

Luc Pattyn

8-Jun-09 4:51

and the cheapest approach probably is a.Length-a.Replace(";","").Length;

[CORRECTION]the single-line approach based on String.Replace is the most compact, however it is slower than an explicit loop checking every character, or looking for the next special character based on String.IndexOf; see my post below[/CORRECTION]

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

modified on Monday, June 8, 2009 1:29 PM

Re: How to count a character in a string?

harold aptroot8-Jun-09 5:52

harold aptroot

8-Jun-09 5:52

Is it? It would be making a new string, and the replace method that takes strings as arguments is extremely complicated.

Re: How to count a character in a string?

Luc Pattyn8-Jun-09 7:17

Luc Pattyn

8-Jun-09 7:17

Hi Harold,

I ran some tests (VS C# 2008, all release build), and the general conclusions are:
- optimum tactic depends on the data, mostly on the fraction of special characters (';') present;
- with lots of ';' the explicit loops are better;
- with few or no ';' string methods are better;
- my single-line approach based on string.Replace never wins;
- when string.Length is present in the for statement, it consumes >30% of the CPU cycles;
- with fewer than 15% of special chars, the winner is IndexOf (see below); for extemely long strings it is up to 4 times faster than the second fastest (explicit loop without Length in for statement).

int n=0;
int start=0;
for (; ; ) {
    int j=test.IndexOf(';', start);
    if (j<0) break;
    n++;
    start=j+1;
}

Luc Pattyn [Forum Guidelines] [My Articles]

The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

Re: How to count a character in a string?

harold aptroot8-Jun-09 7:45

harold aptroot

8-Jun-09 7:45

Cool good to know! Smile | :)

Instant 5

zedgraph

yankoon8-Jun-09 3:06

yankoon

8-Jun-09 3:06

Hi all,

i have 1 project to create dll for foxpro apps to call.
now i need to create 2 line of line chart but it wont work. now it just show 1 line.

//Line
LineItem lineItemCurve = graphPaneChart.AddCurve(null, null, null, Color.Aqua, SymbolType.Circle);
LineItem lineItemCurve2 = graphPaneChart.AddCurve(null, null, null, Color.Red, SymbolType.Diamond);

foreach (double[] daDashboardCharInfo in dashboardChartInfo.ValueSet)
{
lineItemCurve = graphPaneChart.AddCurve(dashboardChartInfo.ValueSetTitle, null, daDashboardCharInfo, Color.Aqua, SymbolType.Circle);
lineItemCurve2 = graphPaneChart.AddCurve(dashboardChartInfo.ValueSetTitle, null, daDashboardCharInfo, Color.Red, SymbolType.Diamond);
}
lineItemCurve.Symbol.Fill = new Fill(Color.Aqua);
lineItemCurve.Symbol.Size = 6;
lineItemCurve.Line.Width = 1.2F;

lineItemCurve2.Symbol.Fill = new Fill(Color.Red);
lineItemCurve2.Symbol.Size = 6;
lineItemCurve2.Line.Width = 1.2F;

Thanks.

Dynamically adding checkboxes in datagridview.

deepseeindeepsy8-Jun-09 3:02

deepseeindeepsy

8-Jun-09 3:02

Hi there,
I want to add dynamically checkboxes to the datagridview rows which displays data on textchange event of a textbox.

On clicking checkboxes I want to go for further coding.

Please help.

Re: Dynamically adding checkboxes in datagridview.

yankoon8-Jun-09 3:11

yankoon

8-Jun-09 3:11

Hi,

from the dategridview, you can select edit columns and click "add" and for columntype just select

"DataGridViewCheckBoxColumn".

HTH,
Jeff.

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