Re: math and statistical functions - C# Discussion Boards

Re: arrays, stucts and static members - hmmm...

Nnamdi Onyeyiri26-Jul-02 9:49

26-Jul-02 9:49

im not - thats why its static.

Abor is in a class called ServerCommand

SrvCmd is a struct, which ive used to make the Abor object.

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Re: arrays, stucts and static members - hmmm...

leppie26-Jul-02 10:09

leppie

26-Jul-02 10:09

Nnamdi Onyeyiri wrote:
im not - thats why its static.

You are!!!

public static SvrCmd Abor = new SvrCmd();

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Re: arrays, stucts and static members - hmmm...

Nnamdi Onyeyiri26-Jul-02 10:12

Nnamdi Onyeyiri

26-Jul-02 10:12

im iticating a static member of type svrcmd in another class, because i want each of the static variables to hold two pieces of information.

anywayx, no need to get ur knickers in a twist, rama solved it for me, i had to put the code where i assigned a value to Abor in a constructos.

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Re: arrays, stucts and static members - hmmm...

Nnamdi Onyeyiri26-Jul-02 9:04

Nnamdi Onyeyiri

26-Jul-02 9:04

ive found a hack for stoping a problem with the Abor.Cmd Abor.Description bit, i gave the SvrCmd() struct a contructor, and set the values in that. Big Grin | :-D

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Taking the system tray a step further

sasdav26-Jul-02 7:15

sasdav

26-Jul-02 7:15

Thanks to help from several people I can now get my NotifyIcon to display text instead of an image, and it can change at run time. Very cool. The next logical step, of course, is to display text instead of an icon.
Basically, I'd like to replace the System Tray clock with my own clock so I can setup different formats, etc.
So, my question is, how can I draw TEXT in the system tray instead of an icon?

thanks

DataGridColumnStyle Class

stephen woolhead26-Jul-02 6:37

stephen woolhead

26-Jul-02 6:37

I have this class that I have derived from DataGridColumnStyle and all is working well apart from one issue.

In my test program I have created a DataSet at runtime and created a table with 3 columns, the table is set to the datasource for the grid. One of the columns is set to readonly.

Now my problem is that I can't seem to find anyway to detect this from within my derived DataGridColumnStyle class. The DataGridTextBoxColumn class seems to manage this feat somehow. For me I just get an exception thrown from DataGrid.CommitEdit() telling me that an object reference is not set to an object when I try to commit the change.

Anyone got any ideas on how I could dected the the DataSet.DataTable.DataColumn is read only?

Thanks

Stephen.

math and statistical functions

troz26-Jul-02 4:51

troz

26-Jul-02 4:51

hello
I'm looking for a nice class containing high level math or statistical functions. Indeed I only know System.Math that isn't enough.
Notably, I've to use the normsdist function (an excel statistical function)
Does anybody know if such a class exist in .net or on the web, or how to create this function

Excel Help :

Returns the normal distribution for the specified mean and standard deviation. This function has a very wide range of applications in statistics, including hypothesis testing.

Syntax

Returns the standard normal cumulative distribution function. The distribution has a mean of 0 (zero) and a standard deviation of one. Use this function in place of a table of standard normal curve areas.

Syntax

NORMSDIST(z)

Z is the value for which you want the distribution.

Thanks a lot

Re: math and statistical functions

Richard Deeming26-Jul-02 5:32

Richard Deeming

26-Jul-02 5:32

Look at: http://ce597n.www.ecn.purdue.edu/CE597N/1997F/students/michael.a.kropinski.1/project/tutorial[^]

public class Stats {
    static readonly double root2Pi = Math.Sqrt(2.0 * Math.PI);

    public static double normDist(double y) {
        return Math.Exp(-(y*y)/2.0) / root2Pi;
    }
    public static double normDist(double y, double mean, double stdDev) {
        double yStd = y - mean;
        return Math.Exp(-(yStd*yStd)/(2.0 * stdDev * stdDev)) / (stdDev * root2Pi);
    }
}

Re: math and statistical functions

troz28-Jul-02 20:46

troz

28-Jul-02 20:46

thx Richard
but what I need isn't the density function, that is calculable from the Math class, but the integral of this density.
But with the other post, I will surely find what I need
thx for your help
troz

Re: math and statistical functions

troz28-Jul-02 22:08

troz

28-Jul-02 22:08

there is the cumulative fonction in addition of your first formula
caution : this is an approximation, found on http://www.pitt.edu/~wpilib/gaussfaq.html
this is only available for y>=0, the precision is 5 digits
and it's only for mean =0 and stdDev = 1

public class Stats
{
static readonly double root2Pi = Math.Sqrt(2.0 * Math.PI);
public static double normDist(double y)
{
return Math.Exp(-(y*y)/2.0) / root2Pi;
}
public static double normDist(double y, double mean, double stdDev)
{
double yStd = y - mean;
return Math.Exp(-(yStd*yStd)/(2.0 * stdDev * stdDev)) / (stdDev * root2Pi);
}
//Attention : CumulnormDist est une approximation (à 10^-5 pres)
//De plus, elle n'est correcte que pour x>=0
//et pour m=0 et sigma = 1 !
public static double CumulnormDist(double y)
{
double t = 1/(1 + 0.33267 * y);
double norm = Stats.normDist(y);
double p = 1 - norm * (0.4361836*t - 0.1201676 *t*t + 0.9372980 * t*t*t);
return(p);
}
}

Re: math and statistical functions

leppie26-Jul-02 9:05

leppie

26-Jul-02 9:05

http://www.cdrnet.net/projects/nmath/

This mite help Smile | :)

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Re: math and statistical functions

troz28-Jul-02 20:47

troz

28-Jul-02 20:47

thx a lot, it seems nice

troz

Setting/changing attributes at runtime

leppie25-Jul-02 23:52

leppie

25-Jul-02 23:52

Hi all,

Is there a way of changing (or setting ) attributes (specifically ReadOnly) at runtime? I have looked at the CustomAttributeBuilder class but it seems to be difficult to understand and apply Frown | :(

. I could be wrong.

Anyone?

Thanx all Smile | :)

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Re: Setting/changing attributes at runtime

James T. Johnson26-Jul-02 1:21

James T. Johnson

26-Jul-02 1:21

Nope, at least none that I know of.

Attributes are part of a types meta-data which is created at compile time so they aren't things that can be added and removed at runtime.

I think that CustomAttributeBuilder is used to create new Attributes for use in your Reflection.Emit generated code.

James
"Java is free - and worth every penny." - Christian Graus

Re: Setting/changing attributes at runtime

leppie26-Jul-02 2:05

leppie

26-Jul-02 2:05

O dear, but thanx anyways James Smile | :)

Maybe theres another way to do what i need. OK, what I need is a property that have a Get and a Set, but the Set should only be active at at certain application states.

Is this possible without having to dig thru all them Builder classes again?

UPDATE: the following does the job, but its still "editable" in a property grid. Can I make it "disabled" in some way so the user cant edit it?

public int Slots
{
    get{return slots;}
    set{if (state == State.Stopped)slots = value;}      }

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Re: Setting/changing attributes at runtime

jparsons26-Jul-02 3:06

jparsons

26-Jul-02 3:06

leppie wrote:
UPDATE: the following does the job, but its still "editable" in a property grid. Can I make it "disabled" in some way so the user cant edit it?

What exactly are you trying to do?

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Re: Setting/changing attributes at runtime

leppie26-Jul-02 4:41

leppie

26-Jul-02 4:41

Im trying to mess with your mind, no just kidding;P

I'm using a propertygrid to monitor a class Properties, but some properties should be able to be settable when the class is in a certain state. This is OK code wise , but like I said the Property is still "settable" according to the user (the brainless user that is), but as soon as he tries to enter a new value it will just revert to the current value, but I dont want to even allow this. I want a nice greyed out GridItem.

It doesnt really bother me, but I have allways taken the approach of Programming for the Dummies Smile | :)

, iow what they cant click or change, they cant break, dont even generate interest or you will create an instant 10 finger virus. Mad | :mad:

Anyways, I will look at some of the code from the PropertyGridInternal namespace, it seems my answer mite lie somewhere deep in there.

Thanx Smile | :)

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Re: Setting/changing attributes at runtime

Thomas Freudenberg20-Feb-03 3:51

Thomas Freudenberg

20-Feb-03 3:51

Hi leppie,

have you found any workaround for this issue? My custom control has a property, which should be en/disabled depending on another property. I hope you've found a solution already Unsure | :~

Regards
Thomas

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Re: Setting/changing attributes at runtime

leppie20-Feb-03 5:59

leppie

20-Feb-03 5:59

I think a type convertor could solve this. But you will have to keep track of some static members. Smile | :)

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XML Web Service error on Update()

laphijia25-Jul-02 23:49

laphijia

25-Jul-02 23:49

This is the code of an XML Web Service that Query an SQL Server.
It takes two strings and returns a DataSet.
It's a simple excercise, It query the database, populate a DataSet, modify a Field and Update the changes.

[WebMethod]
public DataSet GetUserData(string szUsername, string szNewLocalName)
{
string szSqlCommand = "SELECT * FROM Locals WHERE Username = '" + szUsername + "'";
SqlConnection myConnection = new SqlConnection(" User ID=sa;Password=password;Initial Catalog=laphijia;Data Source=(local)");
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter(szSqlCommand, myConnection);
DataSet myDataSet = new DataSet();

mySqlDataAdapter.UpdateCommand = new SqlCommand("UPDATE Locals SET LocalName = @LocalName" +
"WHERE Username = @Username", myConnection);

mySqlDataAdapter.UpdateCommand.Parameters.Add("@LocalName", SqlDbType.NVarChar, 25, "LocalName");
SqlParameter workParam = mySqlDataAdapter.UpdateCommand.Parameters.Add("@Username", SqlDbType.NVarChar, 25);
workParam.SourceColumn = "Username";
workParam.SourceVersion = DataRowVersion.Original;

mySqlDataAdapter.Fill(myDataSet, "Locals");

myDataSet.Tables["Locals"].Rows[0]["LocalName"]= szNewLocalName;
mySqlDataAdapter.Update(myDataSet, "Locals");

return myDataSet;
}

I made this with help from the MSDN NET Framework Developer's Guide article Updating the Database with a DataAdapter and the DataSet.

When I try to access the Web Service and Invokes it, I get a 505 Internal Server Error.
I tried to remove the line:
mySqlDataAdapter.Update(myDataSet, "Locals");

and it works (it returns the DataSet as XML data, but obviously don't update the DataBase.

What's wrong with my code?
I also tried with the SQL Command Builder, but it's just the same.
Thank You.

"Nelle cose del mondo non e' il sapere ma il volere che puo'."

Re: XML Web Service error on Update()

James T. Johnson26-Jul-02 0:19

James T. Johnson

26-Jul-02 0:19

Try wrapping the Update code with a try/catch and see if something is happening there.

Maybe Alex sees something wrong with the call Wink | ;)

James
"Java is free - and worth every penny." - Christian Graus

Re: XML Web Service error on Update()

laphijia26-Jul-02 0:25

laphijia

26-Jul-02 0:25

I tried changing the UpdateCommand with a custom string like "UPDATE locals SET LocalName = 'New Name' WHERE Username = 'john'"

This Worked, I mean, the Method returned the DataSet, and didn't give a 500 Internal Server Error, anyway the Method was completely USELESS now.

But I figured out that the problem is in the UpdateCommand Sql statement.
What's wrong there?

Username is not the Primary Key, it's only used for Authentication purposes on the final version.

How Can I have a correct Sql Statement, connected with the values that I could modify in the DataSet?

"Nelle cose del mondo non e' il sapere ma il volere che puo'."

Re: XML Web Service error on Update()

James T. Johnson26-Jul-02 0:51

James T. Johnson

26-Jul-02 0:51

The only thing I can see that might be wrong with the SQL Query is that there is no space between the @LocalName parameter and the word WHERE.

If you wrap the dataadapter.update method call with a try/catch you could output any error that is generated, which should give you an idea of what to look for.

James
"Java is free - and worth every penny." - Christian Graus

Re: XML Web Service error on Update()

laphijia26-Jul-02 1:13

laphijia

26-Jul-02 1:13

James T. Johnson wrote:
The only thing I can see that might be wrong with the SQL Query is that there is no space between the @LocalName parameter and the word WHERE.

OMG | :OMG:

Could you believe it was just this?
Da*n!

Thank You,
this is the great thing about The Codeproject, that new eyes see subtle errors! Big Grin | :-D

"Nelle cose del mondo non e' il sapere ma il volere che puo'."

Creating a Textbox that doesn't accept focus

swpo25-Jul-02 18:28

swpo

25-Jul-02 18:28

Hi,
How do I create a textbox that doesn't get the focus even when it is clicked upon (other than setting enabled = false)?

Thanks

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