C# Discussion Boards - CodeProject

5-Nov-07 8:58

I have Access 2003. I need to write a C# app to import the contents of a (very simple) Access 2000 database. In this database are three tables, linked by primary keys. The keys have the datatype of 'number', but when I look at them in Access 2003, they are GUIDs. I can't work out how to write the SQL to get the records associated with a GUID. Based on some reading, I tried this:

OleDbCommand cmd = Myconnection.CreateCommand();
cmd.CommandText = "SELECT * FROM Records where Key = {GUID {" + clientKey + "}}";
dbReader = cmd.ExecuteReader();

but the reader is always empty. What's the syntax for filtering on a number data type that turns out to be a guid ?

Thanks

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Re: Query based on GUID in Access DB [modified]

pmarfleet5-Nov-07 9:51

pmarfleet

5-Nov-07 9:51

Having knocked up a quick sample app, that syntax should work.

In Access, a GUID is the data type for fields of type AutoNumber with the Field Size property set to 'Replication ID'. Is your GUID formatted correctly?

Paul Marfleet

"No, his mind is not for rent
To any God or government"
Tom Sawyer - Rush

Christian Graus5-Nov-07 9:59

5-Nov-07 9:59

I don't know. I am reading it in as a string from the database, and then formatting that string to do the query. The data type in the database is 'number', not GUID. The GUID in the database looks exactly like the string I am getting back and storing for my query.

Yes, the field type is 'replication Id'

-- modified at 16:08 Monday 5th November, 2007

pmarfleet5-Nov-07 10:16

pmarfleet

5-Nov-07 10:16

I changed the data type of the field in my sample app to 'Number' and it still worked OK.

This is the query I used:

SELECT * FROM Table1 WHERE xxx = {GUID {5CC9B07E-5DBE-4C65-9B84-7CBE5B6C523B}};

Paul Marfleet

"No, his mind is not for rent
To any God or government"
Tom Sawyer - Rush

Christian Graus5-Nov-07 10:31

5-Nov-07 10:31

OK - I guess I need to play with it some more then. Thanks.

PIEBALDconsult5-Nov-07 16:10

PIEBALDconsult

5-Nov-07 16:10

When not using a parameter...

I find that simply putting a GUID in quotes works

select * from t where id='01aaad5e-d02e-4c39-8fd0-8d7da3fdd5f4'

Christian Graus5-Nov-07 8:56

5-Nov-07 8:56

Sounds like interesting homework. I'm sure you'll learn a lot writing it. If you get stuck when you've tried to do your own homework ( when you have actual code ), try posting a question here, we'd love to help.

YNick5-Nov-07 11:51

5-Nov-07 11:51

well its actually an assignment and i only need to know how to start it off with a function so that i can use that guide to help me with the rest of the program

Colin Angus Mackay5-Nov-07 13:40

Re: Base Conversion [modified]

5-Nov-07 13:40

NickYan wrote:
well its actually an assignment

What is the difference between homework and an assignment?

NickYan wrote:
i only need to know how to start it off with a function

public string ConvertBase(int sourceBase, int destinationBase, string value)
{
    // Fill in the contents as required.
}

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Colin Angus Mackay5-Nov-07 13:38

5-Nov-07 13:38

Christian Graus wrote:
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

I think that if that is what the function does then it is a very good name for it. Blush | :O

-- modified at 19:49 Monday 5th November, 2007

Actually, it was interesting to see that people just copy my code without really understanding it. I would like to say that it was a deliberate gotcha, but I wrote the article during a bout of insomnia so I probably wasn't thinking my best.

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YNick5-Nov-07 15:51

5-Nov-07 15:51

i only know how to program a simple code with a function that is simple ...not this complicated thing with strings..etc ....

PIEBALDconsult5-Nov-07 16:13

PIEBALDconsult

5-Nov-07 16:13

::Ahem:: This isn't complicated.

Colin Angus Mackay5-Nov-07 22:40

5-Nov-07 22:40

NickYan wrote:
i only know how to program a simple code with a function that is simple ...not this complicated thing with strings..etc ....

Strings are typically covered in the first chapter or two of any introductory text on C#. If you cannot yet handle strings then I'm confused why your tutor is giving you this assignment.

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YNick6-Nov-07 6:27

6-Nov-07 6:27

i got 2 codes separate after trying to do it over and over again:here is the binary to decimal code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

/* Function Prototypes */
int bintodec(int fbase, int number);

int main()
{
int number;
int fbase;
int tobase;
int result;

printf("Enter base from: ");
scanf("%d",&fbase);

printf("Enter your number:");
scanf("%d",&number);

printf("Enter base to convert to: ");
scanf("%d",&tobase);

result = bintodec(fbase,number);

printf("The result is:%d", result);

system("PAUSE");
return 0;

}

int bintodec(int fbase, int number)
{
int bin[256];
int counter =0;
int counterR =0;
int quo =1 ;
int result =0;
int result1 =0;
int res[256];
static int sum =0;

while(quo>0)
{
quo= number/10;
bin[counter] = number%10;
number=quo;
counter++;
}

while (counter>0)
{
result = pow(fbase, (counter-1));
result1=result*bin[counter-1];
res[counterR]=result1;
counter--;
counterR++;
}

while (counterR > 0)
{
sum = sum + res[counterR-1];
counterR--;
}

return sum;

}

and the decimal to binary code :

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
int tobase=0;
int number =0;
int counter = 0;
int bin [25];
int quo = 1;

printf("Enter your number:");
scanf("%d",&number);

printf("Enter base to convert to: ");
scanf("%d",&tobase);

while (quo!= 0)
{
quo= number/tobase;
bin[counter] = number%tobase;
counter ++;
number=quo;
}

while (counter > 0)
{
printf( "%d", bin[counter-1]);
counter --;
}

system("PAUSE");
return 0;
}

Now i need to know how to get both of these codes into 1 complete source code for bases conversion.and also asking the user to either convert decimal to binary vice-versa ......
this is the furthest i can go so please help me.

Colin Angus Mackay6-Nov-07 6:50

Re: Base Conversion [modified]

6-Nov-07 6:50

The above code is for C or C++ not C#. Are you sure you are in the right forum?

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YNick6-Nov-07 7:28

6-Nov-07 7:28

it is an ansi c program not c++ .....i think im in the wrong forum my apologies....i dont kno where is the rite forum cause i dont want c++ i want C only

-- modified at 13:33 Tuesday 6th November, 2007

Colin Angus Mackay6-Nov-07 9:03

6-Nov-07 9:03

C++ is the superset of C. If you say you are using C they will be able to help in the C++ forum most likely.

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EventArgs

half-life5-Nov-07 7:35

5-Nov-07 7:35

Hi,

i have a User Control i've created
When a property is changed i like to raise an event
in the Form Hosting The user control
but i also want to pass a value to The Form

i've Done this :

<br />
//In The UserControl :<br />
<br />
public event EventHandler MyVarChanged;<br />
<br />
private void OnChanged(FireEventArgs e) <br />
{<br />
 if (MyVarChanged != null)<br />
     MyVarChanged(this, e);<br />
}<br />
<br />
and in the Set {} of The property:<br />
if (myVar > 10)<br />
    OnChanged(EventArgs.Empty);<br />

in The Form :

<br />
private void userControl11_MyVarChanged(object sender, EventArgs e)<br />
{<br />
  // Do Something          <br />
}<br />

So Far So Good
but i like to pass a parameter
How Do I continue...

THNKS Smile | :)

Have Fun
Never forget it

Judah Gabriel Himango5-Nov-07 7:58

Judah Gabriel Himango

5-Nov-07 7:58

To pass a parameter, don't use EventArgs. Create a new class deriving from EventArgs that contains your information. The call OnChanged(new MySpecialEventArgs(...)) to raise the event and pass parameters to the handlers.

Tech, life, family, faith: Give me a visit.
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Judah Himango

half-life5-Nov-07 8:07

5-Nov-07 8:07

Yeh i figured that

But Got Stucked

i've created that derived like this :

<br />
public class MyVarChangedEventArgs: EventArgs<br />
     {<br />
        public bool sState;<br />
<br />
        public MyVarChangedEventArgs(bool state) <br />
        {<br />
            this.sState = state;<br />
        }<br />
     }<br />

And Changed all other like this :

<br />
//in the property:<br />
if (myVar > 10)<br />
   OnChanged(new MyVarChangedEventArgs(true));<br />
//<br />
public event EventHandler MyVarChanged;<br />
<br />
private void OnChanged(MyVarChangedEventArgs e) <br />
{<br />
 if (MyVarChanged != null)<br />
     MyVarChanged(this, e);<br />
}<br />

but when i open the
e. in The form i do not see the value

am i missing something
Maybe i did not understood the idea that well

THANK Smile | :)

Have Fun
Never forget it

Re: EventArgs [modified]

TJoe5-Nov-07 8:12

TJoe

5-Nov-07 8:12

You need to either change your event declaration to use your custom EventArgs, like so:

public event EventHandler<MyVarChangedEventArgs> MyVarChanged;

Or you can case the EventArgs in your event handler to your custom EventArgs. Basically, the framework things it's an instance of EventArgs, but actually it's an instance of MyVarChangedEventArgs. The first option is your best bet though.

-- modified at 14:18 Monday 5th November, 2007

Take care,
Tom

-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com

half-life5-Nov-07 8:15

5-Nov-07 8:15

YEH

I've Got IT
and Changed IT

Again THANKS

Smile | :)

Have Fun
Never forget it

half-life5-Nov-07 8:14