Change DataType in database - C# Discussion Boards

Re: sound slider

buachaill cliste20-Apr-09 10:10

buachaill cliste

20-Apr-09 10:10

I was going to do that but I kept getting a DNS error Confused | :confused:

But I can go everywhere else lol
Just when ya want it Big Grin | :-D

Write image as Indexed PNG C#

Steve_20-Apr-09 6:53

Steve_

20-Apr-09 6:53

Hi,

I have an instance of Bitmap that I want to save as an PNG with Indexed colour mode. How can I do this in .NET?

Thanks,

Steve

Re: Write image as Indexed PNG C#

buachaill cliste20-Apr-09 9:07

buachaill cliste

20-Apr-09 9:07

Don't know about indexed colour as I've never had the necessity to do it before and google might help Wink | ;)

but this:

Bitmap bmp = new Bitmap(x,y);
            bmp.Save("c:\\bmp", System.Drawing.Imaging.ImageFormat.Png);

Re: Write image as Indexed PNG C#

harold aptroot20-Apr-09 9:42

harold aptroot

20-Apr-09 9:42

That always saves as ARGB png as far as I know..

Re: Write image as Indexed PNG C#

buachaill cliste20-Apr-09 9:45

buachaill cliste

20-Apr-09 9:45

Oh ok. I didn't know Big Grin | :-D

Just tryin' to help Smile | :)

Re: Write image as Indexed PNG C#

Luc Pattyn20-Apr-09 10:01

Luc Pattyn

20-Apr-09 10:01

Hi,

I don't think .NET supports indexed colors for PNG.

This MSDN page[^] says PNG needs 0 bytes for parameters, so there is nothing to choose from.

Smile | :)

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Re: Write image as Indexed PNG C#

Steve_24-Apr-09 15:41

Steve_

24-Apr-09 15:41

For anyone else who wants to achieve this, the FreeImage project provides support for a large number of image codecs and colour modes and has bindings for C#. It is what I used to create a PNG8 file.

Steve

Change DataType in database

andymo220-Apr-09 6:50

andymo2

20-Apr-09 6:50

I'm hoping someone can help me here ...

I have a project that is working well connecting to an Access database file, making queries etc. I discovered that one of the fields in the database is of the wrong type (it is Int32, i want it Text).
- I changed the field type in the database (via Designer View in Access)
- I changed the field type in DataSet in my project (DatabaseDataSet.xsd)
- I changed the data type in the .Add routine.

However, when I compile, the tableadapter .Update command complains about not being able to convert String to Int32. I can't find what else needs to be changed!

Any ideas please ?

Andy

Re: Change DataType in database

Mycroft Holmes20-Apr-09 14:27

Mycroft Holmes

20-Apr-09 14:27

God I hate MS adapters. Destroy the adapter and rebuild it on the changed table.

The problem with the adapters is the dev who knows nothing else has no idea how they work and therefore when something goes wrong gets stuck with nowhere to go. Recommendation - do some research into a decent Data Access Layer (DAL) there are lots of samples out there and if you are serious about being a dev you need to be able to build one! Sorry rant over.

Never underestimate the power of human stupidity
RAH

Error - Attempted to read or write protected memory

Kevin Marois20-Apr-09 6:32

Kevin Marois

20-Apr-09 6:32

I had this code working yesterday. Today I get "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."

Here's the code. It errors on the oSheet.SaveAs line:

Microsoft.Office.Interop.Excel.Application oXL;
Microsoft.Office.Interop.Excel._Workbook oWB;
Microsoft.Office.Interop.Excel._Worksheet oSheet;

oXL = new Microsoft.Office.Interop.Excel.Application();
oWB = (Microsoft.Office.Interop.Excel._Workbook)(oXL.Workbooks.Add(Missing.Value));
oSheet = (Microsoft.Office.Interop.Excel._Worksheet)oWB.ActiveSheet;

Reader = new StreamReader(ExportParams.sSourceFileName);

iRow = 0;
sSourceRow = Reader.ReadLine();

while (sSourceRow != null)
{
    iRow++;
    string[] aWords = sSourceRow.Split(',');

    oSheet.Cells[iRow, 1] = aWords[0];
    oSheet.Cells[iRow, 2] = aWords[1];
    oSheet.Cells[iRow, 3] = aWords[2];

    sSourceRow = Reader.ReadLine();
}

Reader.Close();

if (File.Exists(ExportParams.sResultFileName))
{
    File.Delete(ExportParams.sResultFileName);
}

oSheet.SaveAs(ExportParams.sResultFileName,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing,
        Type.Missing);

oXL.Quit();

Everything makes sense in someone's mind

How to get System Memory in C#.net windows application?

Narendra Reddy Vajrala20-Apr-09 6:06

Narendra Reddy Vajrala

20-Apr-09 6:06

Hi ,
can anyone tell how to find the system memory using c#.net 3.5 windows application?

Thanks In Advance.
--Naren
Blush | :O

Re: How to get System Memory in C#.net windows application?

harold aptroot20-Apr-09 7:11

harold aptroot

20-Apr-09 7:11

I suppose you could P/Invoke to GlobalMemoryStatus[^], for which you will need a MEMORYSTATUS[^]

There could be a better way though..

Re: How to get System Memory in C#.net windows application? [modified]

Luc Pattyn20-Apr-09 7:23

Luc Pattyn

20-Apr-09 7:23

Hi,

use the Ex versions, otherwise you will be in trouble when more than 2GB is present:

[DllImport("kernel32.dll")]
public static extern void GlobalMemoryStatusEx(ref MEMORYSTATUSEX ms);	

public struct MEMORYSTATUSEX {
	/// <summary></summary>
	public int Length;			// DWORD
	/// <summary></summary>
	public int MemoryLoad;			// DWORD
	/// <summary></summary>
	public long TotalPhys;			// DWORDLONG
	/// <summary></summary>
	public long AvailPhys;			// DWORDLONG
	/// <summary></summary>
	public long TotalPageFile;		// DWORDLONG
	/// <summary></summary>
	public long AvailPageFile;		// DWORDLONG
	/// <summary></summary>
	public long TotalVirtual;		// DWORDLONG
	/// <summary></summary>
	public long AvailVirtual;		// DWORDLONG
	/// <summary></summary>
	public long AvailExtendedVirtual;	// DWORDLONG
}

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modified on Monday, April 20, 2009 2:29 PM

Issue with the GzipStream Class

ramz_g20-Apr-09 5:39

ramz_g

20-Apr-09 5:39

Hi,

I am trying to include a compression mechanism in my application. I just went through the one that microsoft provides : GZipStream class... I used the sample code given in msdn and tried to compress files... It worked well for text and document files... But when i tried to compress an exe file, say 100mb size, the compressed file that i get is of size more than 130mb... Can anyone please tell me whether this is a problem with the GZipStream Class?

Thanks in advance,
ramz_g

Re: Issue with the GzipStream Class

Rolando CC20-Apr-09 11:27

Rolando CC

20-Apr-09 11:27

Hi,

First: Is more easy to compress text files than .exe,
Second: From msdn: http://msdn.microsoft.com/en-us/library/system.io.compression.gzipstream.aspx[^]

The compression functionality in DeflateStream and GZipStream is exposed as a stream. Data is read in on a byte-by-byte basis, so it is not possible to perform multiple passes to determine the best method for compressing entire files or large blocks of data. The DeflateStream and GZipStream classes are best used on uncompressed sources of data. If the source data is already compressed, using these classes may actually increase the size of the stream.

So I think in some way maybe the .exe is already compressed.
Suspicious | :suss:

Re: Issue with the GzipStream Class

ramz_g20-Apr-09 19:08

ramz_g

20-Apr-09 19:08

Hi Rolcr,

Thanks for the reply. And yes, I could understand that using those classes to compress files that are already compressed may increase the size. But there is something interesting. I downloaded the gzip.exe from GNU's website and used it to compress a few files. I could find that the size of an exe file reduced by about 5mb... Whereas, using the above classes, the size of the same file increased by more than 30mb. Also, both (gzip.exe and the GZipStream class) returned similar results when applied to .txt and .doc files. Please give me your opinion on this.

Thanks,
ramz_g

Re: Issue with the GzipStream Class

Rolando CC21-Apr-09 3:40

Rolando CC

21-Apr-09 3:40

Yeah, I have listen that in other webs, and seems to be a problem with the GZipStream class and files that had been already compressed, check this:

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=93636[^][^]

Workaround?
Use : http://www.codeplex.com/DotNetZip[^]

Cool | :cool:

Re: Issue with the GzipStream Class

ramz_g21-Apr-09 7:37

ramz_g

21-Apr-09 7:37

Hi Rolcr,

Ya.. Even i browsed through all these sites earlier today and found that there are some issues with GZipStream... Anyways, thanks for the replies...

ramz_g

TableAdapterManager.UpdateAll problem : [ Concurrency violation ]

hdv21220-Apr-09 5:28

hdv212

20-Apr-09 5:28

Hi I'm using TableAdapterManager to update relational data. when i insert a master row then insert some child rows and then press update, the following exception occure on UpdateAll method :

Concurrency violation: the UpdateCommand affected 0 of the expected 1 records

i know solution of this problem is handle BindingSource.AddingNew event of child table, if i using BindingSource (see this link: http://msdn.microsoft.com/en-us/library/bb384432.aspx[^]), but i don't use BindingSource and my problem is that how to solve this issue without BindingSource ?
Thanks

Icon in a textbox

edlanka20-Apr-09 4:56

edlanka

20-Apr-09 4:56

I have a type ahead textbox and on each key press I post back to the server. while the textbox is waiting for the results I would like to display a spinner icon next to the text in the textbox. this spinner icon would indicate that the textbox is waiting for the results.

I have looked at various properties of the text box and couldn’t any property which would allow me to do that.

any suggestions would be appreciated..
thanks,
kar

Re: Icon in a textbox

Ian McCaul20-Apr-09 5:26

Ian McCaul

20-Apr-09 5:26

I would recommend you look at the AJAX tool kit and use an update panel with an update progress control and respond to the textbox.textchanged event. You may have to set auto postback to true on it as well. This article may help for the AJAX peice.

The UpdateProgress Control of ASP.NET AJAX Extensions[^]

Hope this helps.

Re: Icon in a textbox

edlanka20-Apr-09 5:33

edlanka

20-Apr-09 5:33

Thanks for the info.. The Text box i wam working on is Winforms textbox. Is there a similar thing that works in a Winforms environment..
Thanks
kar

Re: Icon in a textbox

Ian McCaul20-Apr-09 5:40

Ian McCaul

20-Apr-09 5:40

Oh I thought you were using ASP.NET since you were sending back to server (what I get for assuming)... You can still respond to the TextBox.TextChanged event. This fires after any input into the textbox. You can use an animated gif to put into an image control to be visible while you are performing whatever operation during the event and set it to visible = false when your processing is complete.

private void currencyTextBox_TextChanged(object sender, EventArgs e)
{
    imageProgress.Visible = true;
    Application.DoEvents();

    ... // Processing

    imageProgress.Visible = false;
    Application.DoEvents();
}

You may have an issue with setting the visiblilty in the current thread... the Application.DoEvents() may solve that, but may not, you may need to look at doing the proccessing on a different thread, you could use a backgroundworker for doing that and it is fairly easy to implement.

Hope this helps.

Re: Icon in a textbox

edlanka20-Apr-09 6:49

edlanka

20-Apr-09 6:49

This one helps.. but the imagecontrol is seperate from the textbox. In my scenario the image control is inside the textbox.
more specifically on the right most side of the textbox where its spinning while waiting for the results to come back..

Could u let me know how I could tie up the image control inside the textbox.
Thanks,
kar

Re: Icon in a textbox

Mbah Dhaim20-Apr-09 7:15

Mbah Dhaim

20-Apr-09 7:15

try using your own user control that contains textbox and image control,
add event begin and end progress to trigger visibility of your image control

hope it helps

dhaim
ing ngarso sung tulodho, ing madyo mangun karso, tut wuri handayani. "Ki Hajar Dewantoro"
in the front line gave a lead, in the middle line build goodwill, in the behind give power support

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