static variables?

[yellow1912]

Hi, I'm very new to C#, in fact I dont know anything about it. Im
having problem with its static variables. I used static variables alot
in C++, but seem like C# doesnt allow it inside a function the way C#
do, so how can you handle recursive functions that need static
variable.

One more thing, I have a variable like this:
OracleDataReade r dr = GetDataReader(s ql,conn, out errMsg);
How can I make dr static to use in my recursive function?

PS: Sorry to sound like a newbie, but Im actually am. I'd really
appreciate any help. Thanks

[Daniel O'Connell [C# MVP]]

"ye********@yah oo.com" <sh***********@ gmail.com> wrote in message
news:11******** **************@ g49g2000cwa.goo glegroups.com.. .

Hi, I'm very new to C#, in fact I dont know anything about it. Im
having problem with its static variables. I used static variables alot
in C++, but seem like C# doesnt allow it inside a function the way C#
do, so how can you handle recursive functions that need static
variable.
You either pass the variable via a parameter or you use a local class field.
One more thing, I have a variable like this:
OracleDataReade r dr = GetDataReader(s ql,conn, out errMsg);
How can I make dr static to use in my recursive function?
public class C
{
....
OracleDataReade r dr;
public void SetConnection()
{
dr = GetDataReader(s ql, conn,out errMsg);
}
}
I'd strongly consider passing the reader to the next method as a parameter
however.
PS: Sorry to sound like a newbie, but Im actually am. I'd really
appreciate any help. Thanks

[Kevin Spencer]

Yrsh, it kind of sucks that you can't declare static method variables, but
there you are. Declare them at class scope, as private fields, instead.

--
HTH,

Kevin Spencer
Microsoft MVP
..Net Developer
There's a seeker born every minute.
- Dr. "Happy" Harry Cox

"ye********@yah oo.com" <sh***********@ gmail.com> wrote in message
news:11******** **************@ g49g2000cwa.goo glegroups.com.. .

Hi, I'm very new to C#, in fact I dont know anything about it. Im
having problem with its static variables. I used static variables alot
in C++, but seem like C# doesnt allow it inside a function the way C#
do, so how can you handle recursive functions that need static
variable.

One more thing, I have a variable like this:
OracleDataReade r dr = GetDataReader(s ql,conn, out errMsg);
How can I make dr static to use in my recursive function?

PS: Sorry to sound like a newbie, but Im actually am. I'd really
appreciate any help. Thanks

[yellow1912]

Thanks^^. But then wouldnt the dr be cleared each time the function is
called?

Here is my code, and I know it's wrong obviously, but cant figure out
how to fix it
private static bool Connection( string fromloc, string
toloc,OracleCon nection conn)
{

string sql = "SELECT FLIGHTNO,LEGORD ER,TOLOC FROM LEG WHERE FROMLOC =
'" + fromloc + "'";
string errMsg = "";

OracleDataReade r dr = GetDataReader( sql, conn, out errMsg );
if ( errMsg != "" )
{
Console.WriteLi ne( errMsg );
return false;
}
if ( dr == null )
{
Console.WriteLi ne( "No result" );
return false;
}
while( dr.Read() )
{

if (dr[2].ToString()==to loc)
{
Console.WriteLi ne("flight: " + dr[0] + " legorder: " + dr[1]);
return true;
}
else
return(Connecti on(dr[2].ToString(),tol oc,conn));
}
//dr.Close(); //close the DataReader
//dr.Dispose();
//conn.Close(

[Truong Hong Thi]

I do like static method variables but it appears the CLR does not
support it. VB.NET supports static method variables - its compiler
compiles such variables into private class fields.

[Truong Hong Thi]

>But then wouldnt the dr be cleared each time the function is

called?

Then you could initialize the var at declaration or in constructor.
If that is not posible, in the method check and only init if it is null.

[yellow1912]

Im trying to understand it.... Can anyone give me an example (any) or
better on the code I posted:

Task: given start-end location, find all possible connections.
If the function runs the first time and I get the first dr, then it
calls itself and i get the 2nd dr,... so on till the n dr. Then it goes
back from n to n-1.... to 1, how can I keep every dr from being deleted
each time the function called itself? Or is there a better way to solve
this prblem?

private static bool Connection( string fromloc, string
toloc,OracleCon nection conn)
{

string sql = "SELECT FLIGHTNO,LEGORD ER,TOLOC FROM LEG WHERE FROMLOC =
'" + fromloc + "'";
string errMsg = "";

OracleDataReade r dr = GetDataReader( sql, conn, out errMsg );
if ( errMsg != "" )
{
Console.WriteLi ne( errMsg );
return false;
}

if ( dr == null )
{
Console.WriteLi ne( "No result" );
return false;
}

while( dr.Read() )
{

if (dr[2].ToString()==to loc)
{
Console.WriteLi ne("flight: " + dr[0] + " legorder: " + dr[1]);
return true;
}

else
return(Connecti on(dr[2].ToString(),tol oc,conn));

}
}

[Daniel O'Connell [C# MVP]]

"ye********@yah oo.com" <sh***********@ gmail.com> wrote in message
news:11******** **************@ g14g2000cwa.goo glegroups.com.. .

Im trying to understand it.... Can anyone give me an example (any) or
better on the code I posted:

Task: given start-end location, find all possible connections.
If the function runs the first time and I get the first dr, then it
calls itself and i get the 2nd dr,... so on till the n dr. Then it goes
back from n to n-1.... to 1, how can I keep every dr from being deleted
each time the function called itself? Or is there a better way to solve
this prblem?

A local field would work.

Frankly, I don't see where you are going with your code here, why do you
need to keep old DataReaders around?

[Daniel O'Connell [C# MVP]]

"Kevin Spencer" <ke***@DIESPAMM ERSDIEtakempis. com> wrote in message
news:%2******** ********@TK2MSF TNGP15.phx.gbl. ..

Yrsh, it kind of sucks that you can't declare static method variables, but
there you are. Declare them at class scope, as private fields, instead.

Static variables are little more than fields with constrained access anyway.
I've never found them to be terribly useful and I do think they blur the
lines a bit much. I find that it is too easy to consider a field as local
state, even with the static marker. --
HTH,

Kevin Spencer
Microsoft MVP
.Net Developer
There's a seeker born every minute.
- Dr. "Happy" Harry Cox

"ye********@yah oo.com" <sh***********@ gmail.com> wrote in message
news:11******** **************@ g49g2000cwa.goo glegroups.com.. .

Hi, I'm very new to C#, in fact I dont know anything about it. Im
having problem with its static variables. I used static variables alot
in C++, but seem like C# doesnt allow it inside a function the way C#
do, so how can you handle recursive functions that need static
variable.

One more thing, I have a variable like this:
OracleDataReade r dr = GetDataReader(s ql,conn, out errMsg);
How can I make dr static to use in my recursive function?

PS: Sorry to sound like a newbie, but Im actually am. I'd really
appreciate any help. Thanks

[yellow1912]

If I have table flight with flightno, from, to,.. I want my program to
return all possible connections ,given from X and to Y.
Here is the solution I come up with:
1.Search all flights from X
For example I get:

flightno from to
1 X Y
2 X A
3 X B

2.Loop thru the result
a. If the flight's destination is Y, return this path
b. Else, Search all flights goes from this result's location (for
example: all flights from A)

I hope I make it clearer? Now you see why I want to keep the old
datareader?