Re: How to convert a string to double with out lossing precission?? - C# Discussion Boards

Ennis Ray Lynch, Jr.3-Jun-09 2:42

3-Jun-09 2:42

Check out the code MS provides for the Windows Mobile Gps, http://msdn.microsoft.com/en-us/library/ms881362.aspx[^] (Sample code comes with the SDK)

It contains many C structs written in C#, fairly cool. (Although, the sample like all MS samples doesn't work out of the box)

Need custom software developed? I do C# development and consulting all over the United States.

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: convert C struct into C#.net

Rob Philpott3-Jun-09 2:53

Rob Philpott

3-Jun-09 2:53

I'm not so hot on all that interop stuff and its a guess, but you could try this:

[StructLayout(LayoutKind.Sequential)]
public struct _MT_EVENT
{
	public long TimeStamp;
	public ulong UserStatus; // Not used by API
	public ulong EventCode; // Event Code
	public ulong SubReason; // Event sub-reason
	public ulong XtraInfo; // Extra information, e.g. termination
	public ulong FuncCode; // Function active when this event occurred
	public ushort Board; // Board ID
	public ushort Channel; // Global Channel ID (GCI)
	public IntPtr ptrBuffer; // Related play/record buffer pointer
	public ulong DataLength; // Byte length of data accessed (played/recorded)
	public IntPtr ptrXtraBuffer; // Pointer to xtra buffer
	public ulong XtraBufferLength; // Length of buffer pointed by ptrXtraBuffer
	public ulong XtraDataLength; // Length of data in buffer pointed by ptrXtraBuffer
	public ulong EventFlag; // Falgs of the following:
}

Regards,
Rob Philpott.

Re: convert C struct into C#.net

Luc Pattyn3-Jun-09 3:41

Luc Pattyn

3-Jun-09 3:41

size warning: in.NET long/ulong are 64-bit integers, in most other languages when targettingt a 32-bit CPU they just take 32-bit.

http://www.pinvoke.net[^] holds lots of useful interop stuff, however it also contains some mistakes, frequently passing a pointer as int (should be IntPtr).

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.

Re: convert C struct into C#.net

Ennis Ray Lynch, Jr.3-Jun-09 5:16

Ennis Ray Lynch, Jr.

3-Jun-09 5:16

That is the primary reason I encourage (require) programmers on my teams not to use int and long in C# and instead require Int32 and Int64. The same issue comes up a lot in database programming. I am absolutely sick and tired of seeing cast errors in code because a programmer doesn't know what type they are using.

Re: convert C struct into C#.net

eyeshield213-Jun-09 18:40

eyeshield21

3-Jun-09 18:40

thanks alot all...

How to convert a string to double with out lossing precission??

prathapcode3-Jun-09 1:23

prathapcode

3-Jun-09 1:23

Hi,

I have a string with value "111733394601234567094987654321" . Now i want to divide this with 636. I convert it to double , then im getting 1.1173339460123456E+29 . but these both values are differnt finally im
getting wrong output. can anyone help me.....

Thanks
Prathap

Re: How to convert a string to double with out lossing precission??

Moreno Airoldi3-Jun-09 1:29

Moreno Airoldi

3-Jun-09 1:29

There is no way you can do that with doubles. Since the value is too big even for a 64 bit integer, you should use some 128-bit integer class. See for example this[^] or Google for some more.

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Re: How to convert a string to double with out lossing precission??

Luc Pattyn3-Jun-09 3:45

Luc Pattyn

3-Jun-09 3:45

The latest .NET 4.0 (and Visual Studio 2010) is in beta and offers a BitInteger class which would easily take care of your big integer division, yielding accurate quotient and remainder values.

There also have been some articles on home-brew BigInteger classes here on CP (with varying functionality and quality).

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.

& missing

benjamin yap3-Jun-09 1:12

benjamin yap

3-Jun-09 1:12

Hi, my database has a column called 'course'. I have a value "Game & Entertainment Technology"

when i extract the value using

acc.Course = reader.GetValue(4).ToString();<br />
lblCourse.Text += " " + acc.Course.ToString();

the value becomes Game Entertainment Technology.. the & disappear

Re: & missing

Rob Philpott3-Jun-09 1:21

Rob Philpott

3-Jun-09 1:21

That's because & is used to underline a letter for a shortcut. You need to double it to &&.

acc.Course = reader.GetValue(4).ToString();
lblCourse.Text += " " + acc.Course.ToString().Replace("&", "&&");

Regards,
Rob Philpott.

Re: & missing

Rob Philpott3-Jun-09 1:24

Rob Philpott

3-Jun-09 1:24

Actually, presuming reader is a SqlDataReader and acc.Course is a string you can shorten this to:

acc.Course = reader.GetString(4);
lblCourse.Text += " " + acc.Course.Replace("&", "&&");

Regards,
Rob Philpott.

Re: & missing

benjamin yap3-Jun-09 1:26

benjamin yap

3-Jun-09 1:26

thanks alot!

1 more question. My first screen is a login screen. Therefore i have a username and password textbox.

private void btnLogin_Click_1(object sender, EventArgs e)<br />
{<br />
    bool validate = db.authenticate(tbxUsername.Text, tbxPassword.Text);<br />
    if (!validate)<br />
    {<br />
        MessageBox.Show("Invalid Credentials");<br />
    }<br />
    else<br />
    {<br />
        frmMain main = new frmMain(tbxUsername.Text);<br />
        <br />
        main.Show();<br />
        this.Hide();<br />
        <br />
    }<br />
}

Is it possible to close the login form instead of hiding it? I do a this.close() but after i login everything close.

Also, my db.authenticate is not case sensitive. The password in the database is 'test'. However when i entered 'TEST', it works too.

Re: & missing

Henry Minute3-Jun-09 1:33

Henry Minute

3-Jun-09 1:33

If the login form is the first one created and called from Program.cs, the application classes it as the 'Main' form of the application. When the main form closes, the application closes.

There are loads of examples of using a login form on the web, have a quick google to see how to do it.

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.”

Re: & missing

benjamin yap3-Jun-09 1:38

benjamin yap

3-Jun-09 1:38

Okay. Noted. Thanks

What bout make the password and username case sensitive?

Re: & missing

Henry Minute3-Jun-09 2:03

Henry Minute

3-Jun-09 2:03

You stated that db.authenticate was not case sensitive. I can not find any reference to an authenticate method for any database related classes, so I assume that it is one you have written yourself.
If that is so, take a look at this[^].

I not, I am unable to help.

Re: & missing

benjamin yap3-Jun-09 3:52

benjamin yap

3-Jun-09 3:52

thanks. i found the solution.

inside phpmyadmin, i change the collation to latin1_general_cs.

cs refers to case sensitive

Re: & missing

Rob Philpott3-Jun-09 2:19

Rob Philpott

3-Jun-09 2:19

Certainly you'd want to close the login screen when you're finished with it. There are a few ways to do this. Also, you don't want to do a main.Show() in the login screen - you lose reuse and abstraction if you do that by tightly coupling the login and main screen.

To open the main screen after the login either call ShowDialog() on the login form from the main form's on load event or you can change your main() function to look like this:

[STAThread]
static void Main()
{
	Application.EnableVisualStyles();
	Application.SetCompatibleTextRenderingDefault(false);
	Application.Run(new LoginForm());
	Application.Run(new MainForm());
}

Regards,
Rob Philpott.

Re: & missing

Moreno Airoldi3-Jun-09 1:24

Moreno Airoldi

3-Jun-09 1:24

Ampersand "&" is used as a special character in Windows Forms controls: it will cause the next character to be underlined. You can solve your problem by replacing each ampersand with a double ampersand.

Try something like:

lblCourse.Text += " " + acc.Course.ToString().Replace("&", "&&");

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Sybase connection error...

The_Collector3-Jun-09 0:24

The_Collector

3-Jun-09 0:24

I'm trying to connect to Sybase Server (Adaptive Server Anywhere 6.0) from my C# application but failed to establish a connection.... it seems the C# use a default MSSQL driver. Below is the error:

"An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)"

below is the code:

//string bartsConnect = "Driver={Adaptive Server Anywhere 6.0};SRVR=MyServer;DB=MyDatabase;UID=myUserId;PWD=myPassword";

string myConnection = "server=ServerName;Database=myDatabase;uid=myUserId;pwd=myPassword";
SqlConnection myConnection = new SqlConnection(myConnection);
myConnection.Open();

hope to hear some answers soon,,,, thank you.

xxx

Re: Sybase connection error...

Moreno Airoldi3-Jun-09 0:40

Moreno Airoldi

3-Jun-09 0:40

You are using an SqlConnection, which is specifically for SQL Server.

Try to use an OleDbConnection and you should be all right. Smile | :)

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Re: Sybase connection error...

The_Collector3-Jun-09 4:00

The_Collector

3-Jun-09 4:00

yes, thank you but my problem is the connection string that i can be use to connect to Sybase(Adaptive Server Anywhere 6.0)... most of the examples in the net use access database..... can u give me the right connection string for the above server?...

xxx

Re: Sybase connection error...

Moreno Airoldi3-Jun-09 5:21

Moreno Airoldi

3-Jun-09 5:21

Sorry I have no experience with Sybase, so I cannot help you with connection strings.

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Re: Sybase connection error...

The_Collector3-Jun-09 14:36

The_Collector

3-Jun-09 14:36

thax anyway......

xxx

Exception when making a control button

gwithey3-Jun-09 0:08

gwithey

3-Jun-09 0:08

I am trying to make a button to represent a volume control knob such as on a CD player in c#

The following error has croped up and i cant find any "Useful" information on what could be wrong.

Does anyone know how to resolve this Exception:

"WindowsFormsControlLibrary1.dll' doesn't contain any UserControl types."

Why would the namespace not contain a user control or could i have not linked the dll properly?

Thanx

Re: Exception when making a control button

Moreno Airoldi3-Jun-09 0:21

Moreno Airoldi

3-Jun-09 0:21

I guess you get this error when you try to run your solution (F5) inside Visual Studio.

You cannot directly run a dll, you should set up an executable project in your solution and make it the "Startup Project" for the solution.

For example, create a new Windows Form executable and link your dll in it, in order to test your custom button.

2+2=5 for very large amounts of 2
(always loved that one hehe!)

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.