C# Discussion Boards - CodeProject

LiamD28-Jul-06 2:52

28-Jul-06 2:52

I have an fixed length array :-

Byte[] myArray = new Byte[50];

Now this represents a specific message structure. For example, the sort of thing I want to do is :

1. to read and set a bit field, Byte[25], bit 1
2. to read and set a 5 bit value, Byte[20], bits 0-5
3. to read and set a 32 bit number, Byte[10]

These are just a few examples of what functions I want to perform on the array. But they highlight some of my challanges.

Any thoughts on gneral ways to achieve this?

Thanks,
Liam

Re: Bitfield access to array [modified]

Dustin Metzgar28-Jul-06 3:29

Dustin Metzgar

28-Jul-06 3:29

Well, to set a particular bit in a byte, I would use bitwise operators. The exclusive-or (^) would work:

byte b = 35;
b ^= 0x01;

*Note - This will change the value of the bit. If it's 0, it will be changed to 1, if it's 1 it will be changed to zero.

Of course, it's hard to tell what you mean by bit 1. But to set a particular bit in the byte array is not much different:

byte[] b = new byte[50];
...
b[25] ^= 0x01;

To read the value, you can use a bitwise-and ( & ) :

if (b[20] & 0x1f == a) { ... }

I'm not sure what you mean by setting a 32 bit number on a single byte though.

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Last modified: Friday, July 28, 2006 9:43:29 AM --

struct

honeyman_can28-Jul-06 2:44

honeyman_can

28-Jul-06 2:44

forgive me - I'm new to c#
public struct lookupOjbect
{
string fieldvalue;
public lookupOjbect (string fieldvalue)
{
this.fieldvalue = fieldvalue;
}
}

lookupOjbect lookupObjectRow = new lookupOjbect();
When I want to assign a value to this object then 'fieldvalue' doesnt show with intellisense. e.g. lookupObjectRow.fieldvalue - doesnt show!

Re: struct

wheelerbarry28-Jul-06 2:52

wheelerbarry

28-Jul-06 2:52

it is because fieldvalue is private.
Try

public string fieldvalue
though that is not great oop, and most thing use properties to get around that and keep encapulation, e.g.

private string fieldvalue;

public string FieldValue
{
set { this.fieldvalue = value; }
get { return this.fieldvalue; }
}

thank you

honeyman_can28-Jul-06 3:01

honeyman_can

28-Jul-06 3:01

Re: thank you

Tristan Rhodes28-Jul-06 3:03

Tristan Rhodes

28-Jul-06 3:03

Remember that changing the values in a struct type only affect that particular instance as it is a value type.

If you are planning on implementing a Get / Set accessor, you may want to think about using a class instead.

Re: thank you

Colin Angus Mackay28-Jul-06 3:29

Colin Angus Mackay

28-Jul-06 3:29

The Catalyst wrote:
Remember that changing the values in a struct type only affect that particular instance as it is a value type.

And so what happens in a class if it doesn't "only affect that particular instance"?

The Catalyst wrote:
If you are planning on implementing a Get / Set accessor, you may want to think about using a class instead

Why would a class be better in this instance? What is wrong with putting Get/Set accessors on a struct?

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Re: thank you

Tristan Rhodes28-Jul-06 3:52

Tristan Rhodes

28-Jul-06 3:52

Colin Angus Mackay wrote:
And so what happens in a class if it doesn't "only affect that particular instance"?

It's the old Refference / Value type behavior. I think i worded it badly.
Any change made to a class is reflected through all refferences, making changes to a struct only changes the one you are changing in the local context. (Barring special circumstances)

Colin Angus Mackay wrote:
Why would a class be better in this instance? What is wrong with putting Get/Set accessors on a struct?

I've never seen a Get / Set in a struct, at least, not in the standard CLR libraries. Tho i suppose there must be some, i can't imagine a use for them; All the com interop structs use public fields.

From what i've seen, everything gets set in the ctor. and accessed through read only properties.

Re: thank you

Judah Gabriel Himango28-Jul-06 5:18

Judah Gabriel Himango

28-Jul-06 5:18

The Catalyst wrote:
I've never seen a Get / Set in a struct, at least, not in the standard CLR libraries.

Actually, virtually every struct I've seen in the BCL uses properties: Point, Size, Rectangle, to name a few, all expose their data via properties.

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Re: thank you

Tristan Rhodes28-Jul-06 5:28

Tristan Rhodes

28-Jul-06 5:28

True, but they are all read only. None of them implement a set method, you have to create a new object if you want to use different values.

Re: thank you

Andrew Lygin28-Jul-06 5:42

Andrew Lygin

28-Jul-06 5:42

The Catalyst wrote:
True, but they are all read only. None of them implement a set method

That's wrong. Look at the Point.X for example. You can set it.

I stand corrected.

Tristan Rhodes28-Jul-06 6:14

Tristan Rhodes

28-Jul-06 6:14

Still, pretty pointless. Big Grin | :-D

Re: thank you

Judah Gabriel Himango28-Jul-06 5:54

Judah Gabriel Himango

28-Jul-06 5:54

The Catalyst wrote:
True, but they are all read only.

Have a look at Rectangle.Width, Height, Size, and others.

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Messianic Instrumentals (with audio)
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Judah Himango

Re: struct

Tristan Rhodes28-Jul-06 2:56

Tristan Rhodes

28-Jul-06 2:56

The default accessor property for a field in C# is private, therefore it would only be accessible internaly, and not appear on intellisense. Just wack public infront of it.

Re: struct

Ennis Ray Lynch, Jr.28-Jul-06 3:48

Ennis Ray Lynch, Jr.

28-Jul-06 3:48

public members are a crime

keep fieldValue private.

A man said to the universe:
"Sir I exist!"
"However," replied the Universe, "The fact has not created in me A sense of obligation."

-- Stephen Crane

Re: struct

leppie28-Jul-06 10:46

leppie

28-Jul-06 10:46

If a tree drops in the forest... Smile | :)

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Report Generation C#

peshawarcoder28-Jul-06 2:32

peshawarcoder

28-Jul-06 2:32

I have written code for report in Form_Load event handler as under:

System.Data.SqlClient.SqlDataAdapter adapter = new    System.Data.SqlClient.SqlDataAdapter("Select * From Customers", 
"server=pc1;database=northwind;trusted_connection=true");

System.Data.DataSet ds = new DataSet();
adapter.Fill(ds, "Customers");

CrystalDecisions.CrystalReports.Engine.ReportClass rpt1 = new CrystalDecisions.CrystalReports.Engine.ReportClass();
rpt1.SetDataSource(ds.Tables["Customers"]);
            
CrystalDecisions.Windows.Forms.CrystalReportViewer rptviewer = new CrystalDecisions.Windows.Forms.CrystalReportViewer();
rptviewer.Dock = DockStyle.Fill;
this.Controls.Add(rptviewer);
rptviewer.ReportSource = rpt1;

but it gives me the following error:

Unable to find the report in the manifest resources. Please build the project, and try again.

Can someone help how to generate report in this way?

Thanks for consideration

howto maximize a program if it is minimized ??? help please ...

cmpeng3428-Jul-06 2:11

cmpeng34

28-Jul-06 2:11

hi all,
i have a windows form lets say 'myform'.
i check on myform's load if there is a previous instance of 'myform' running or not.
> if a previous instance runs, then i display an error message and close the secondly opened copy.

but after closing secondly opened instance, i dont know howto maximize the first copy of 'myform' which was minimized on taskbar ?

do u know howto maximize & bring to front the previous myform or at least to blink it like msn messenger ? (when a message received)

thanks in advance,
bye.

Re: howto maximize a program if it is minimized ??? help please ...

Shajeel28-Jul-06 2:29

Shajeel

28-Jul-06 2:29

check this http://www.bobpowell.net/singleinstance.htm[^]

Regards
Shajeel

Re: howto maximize a program if it is minimized ??? help please ...

LongRange.Shooter28-Jul-06 8:47

LongRange.Shooter

28-Jul-06 8:47

this.WindowState

Split string

Rahul.RK28-Jul-06 2:01

Rahul.RK

28-Jul-06 2:01

Hello Frieds,

I just want to ask you that, How to split the string by another string.

Take ex.-

string tosplit = "10***3*2**5";
string delim = "***";

now o/p should be split1 = 10
split2 = 3*2**5

Thanks in Advance.

Rahul Kulkarni.

Re: Split string

jjansen28-Jul-06 2:15

jjansen

28-Jul-06 2:15

Try this:

string[] Parts = tosplit.Split("***", StringSplitOptions.RemoveEmptyEntries);

Re: Split string

Rahul.RK28-Jul-06 2:22

Rahul.RK

28-Jul-06 2:22

Firstly Thanks for your response.

You have suggested "StringSplitOptions".

But i think it is not in the framework-1.1

Can you suggest any other solution.

Rahul Kulkarni

Re: Split string

jjansen28-Jul-06 2:56

jjansen

28-Jul-06 2:56

RahulRKulkarni wrote:
But i think it is not in the framework-1.1

You're right, it's new in Framework 2.0.
Perhaps you can use IndexOf("***") in combination with Substring.

Re: Split string

Dustin Metzgar28-Jul-06 6:27

Dustin Metzgar

28-Jul-06 6:27

Use a regular expression:

Regex re = new Regex(@"\*\*\*");
string[] splits = re.Split(tosplit);

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