Re: hexadecimal convertions and add on datagrid - C# Discussion Boards

4-Feb-07 22:28

hello all,

am making a project that has a datagridview that will be filed from a SQL DB,

1) there si a field in the DB that has a data in hexadecimal format, so how i can fill it after converting it to string.

2) what is the process of allowing the user to add, delete and update on the datagridview directly??

sorry for the ones who see that i ask an easy questions Cry | :((

but they are not easy 4 all of ones as u see :->

Thanks alot
Hamody

gauthee4-Feb-07 23:49

gauthee

4-Feb-07 23:49

hi,

when u write the query to retrieve the data, convert the hexadecimal value to a string so that ur table will not have any column with hexadecimal values.

you can use edit, update, cancel and do the required manipulations on the datagrid, write the required logic in few methods and assign these methods accordingly to the datagrid events!!!

Gautham

Mohammad Daba'an5-Feb-07 0:04

5-Feb-07 0:04

thanks, but how i can convert from hexadecimal to string, io dont know the function to do this.

have u an example on add, delete, update on the datagridview Confused | :confused:

Thanks alot
Hamody

Luc Pattyn5-Feb-07 0:45

Luc Pattyn

5-Feb-07 0:45

Hi,

int.Parse(myString, NumberStyles.AllowHexSpecifier);

will do it; I find the style name confusing, it means read-as-hex but does not
allow the 0x specifier !

Smile | :)

Luc Pattyn

Mohammad Daba'an5-Feb-07 1:02

5-Feb-07 1:02

i tried it as:

string hhhh;
hhhh=int.Parse("ffff", NumberStyles.AllowHexSpecifier).ToString();
MessageBox.Show(hhhh);

use using System.Globalization; as name space

but it hasnt convert the hex to string

what can i do ??? Sigh | :sigh:

Thanks alot
Hamody

Luc Pattyn5-Feb-07 1:21

Luc Pattyn

5-Feb-07 1:21

Your code seems right.

This code snippet works for me:

public override void Run(int arg) {
    hex("12");
    hex("1234");
    hex("1aBd");
    hex("FFFF");
    hex("ffff");
}

public void hex(string s) {
    int i=int.Parse(s,NumberStyles.AllowHexSpecifier);
    log("hex "+s+" = decimal "+i);
}

It produces

hex 12 = decimal 18
hex 1234 = decimal 4660
hex 1aBd = decimal 6845
hex FFFF = decimal 65535
hex ffff = decimal 65535

so I expect your problem is elsewhere.

Smile | :)

Luc Pattyn

gauthee5-Feb-07 0:49

gauthee

5-Feb-07 0:49

datagrid examples:http://www.4guysfromrolla.com/webtech/122300-1.shtml

give me a detailed explaination reg the hexadecimal prblm....

Gautham

Mohammad Daba'an5-Feb-07 1:05

5-Feb-07 1:05

ok thanks first,,,

i mean that i have SQL database table which has a field containg hexadecimal data (arabic converted to hexadecimal) i want 2 show converted data on the datagridview Poke tongue | ;-P

Thanks alot
Hamody

gauthee5-Feb-07 1:27

gauthee

5-Feb-07 1:27

Check this link: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1161100&SiteID=1

Gautham

Marshalling LPVOID

Quiltfish4-Feb-07 21:47

Quiltfish

4-Feb-07 21:47

G'day!

I'm currently writing a program that imports and uses functions from an unmanaged DLL. One of these functions expect as a parameter a struct containing some data (whose types I have previously passed successfully to other functions in the same dll) and an array of a struct containing an LPVOID type and a function pointer(which I have sucessfully passed). I don't understand how marshalling this type should work, if anyone could enlighten me, I'd be most thankful. Heres my current implementation:

<br />
[StructLayout(LayoutKind.Sequential,Pack = 0)]<br />
public struct StructA<br />
{<br />
 // Misc data<br />
 public StructB[] sBArray;<br />
}<br />
<br />
[StructLayout(LayoutKind.Sequential,Pack = 0)]<br />
public struct StructB<br />
{<br />
 [MarshalAs(UnmanagedType.FunctionPtr)]<br />
 public aDelegate delegateMember;<br />
 public object TheProblemChild; //The Unmanaged DLL expects an LPVOID type here<br />
}<br />
<br />
public class Bleh<br />
{<br />
[DllImport("Unmanaged.dll", EntryPoint = "UnmanagedImport")]<br />
        private static extern int UnmanagedImport([MarshalAs(UnmanagedType.Struct)] StructA sA);<br />
 public int CallUnmanagedFunc()<br />
 {<br />
  StructA sA = new StructA();<br />
  SA.sBArray = new StructB[7];<br />
<br />
  //Initialize other data...<br />
<br />
  return UnmanagedImport(sA); //This throws an ArgumentException<br />
 }<br />

The indicated position throws an ArgumentException seemingly no matter what I try. The message is "The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))" and the stacktrace points directly to the imported function. In short (;P), I ask: How can I pass, from managed code to unmanaged, a parameter expected to be of type LPVOID?

Sorry if I overwhelmed you, or maybe turned non understandable. Unsure | :~

Re: Marshalling LPVOID

Martin#5-Feb-07 2:14

Martin#

5-Feb-07 2:14

Look at this article on CP

http://www.codeproject.com/csharp/unmanage.asp?print=true[^]

All the best,

Martin

Re: Marshalling LPVOID

Quiltfish5-Feb-07 2:36

Quiltfish

5-Feb-07 2:36

I was gonna say that I've gone through a bunch of interop articles (both here and elsewhere) with a fine-toothed comb without finding anything, when I found that the field should be an IntPtr managed-side. Roll eyes | :rolleyes:

However, when I tried it (And used the Marshal class to place data in the field) I still get the same exception. Down to the stacktrace. Thanks anyway!

Opacity problems

b43r_3oo34-Feb-07 21:14

b43r_3oo3

4-Feb-07 21:14

hello,

i've got problems with opacity in my splash.

Informations to the inviroment: When I start my app a splash will shown with slowly fade-in effect.

Like it matters if colordepth is 32bit or 16bit, the transparent/white area of my splash (its an non symmetric pictrue and in that reason i'd set the transparencykey to "white") fades-in in black color.. it should by transparent. when i turn the colordepth to 16bit or lower, and the image opacity is 100%, the unneeded area is transparent, if it is 32bit it's white.. what do i wrong??

greetings from germany and sry of my bad english =))

Martin#4-Feb-07 21:41

Martin#

4-Feb-07 21:41

Hello,

Combining Transparents and Opacity doesn't work. (.Net 1.1) Cry | :((

Also had a lot of bad days because of that.

What you can do is, after the "fading" is finished (opacity is 100%), you could call a method like that:

using System.Drawing;
 
public void MakeBackgroundTransparent()
{
	Bitmap Img = new Bitmap(this.BackgroundImage);
	Img.MakeTransparent(Img.GetPixel(0,0));  //Set the coordinates to a point where the transparent color is
	this.BackgroundImage = Img;
}

Hope that helps,

Martin

b43r_3oo34-Feb-07 22:15

b43r_3oo3

4-Feb-07 22:15

Hello Martin,

thanks for fast answering. I developing with .Net 2.0 - why dosen't work? Is there a workaround?

The code wouldn't work.. not at 32bit resolution..

greetings

Jerry

Martin#4-Feb-07 22:41

Martin#

4-Feb-07 22:41

Hello,

b43r_3oo3 wrote:
thanks for fast answering. I developing with .Net 2.0 - why dosen't work? Is there a workaround?

I only know the one I told you.

b43r_3oo3 wrote:
The code wouldn't work.. not at 32bit resolution..

I'm using 32bit resolution and it works for me.

What I found out is that the TransparencyKey property doesn't work on every hardware with 32 bit. If you google for that problem you will find a lot of people sharing this problem.

All the best,

Martin