important coding problem - C# Discussion Boards

Re: How to pick up multiple resultsets from a query

19-Aug-05 2:17

If you get the result into a dataset, the set will contain two tables.

If you use a datareader, use the NextResult method to move on to the next resultset.

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skooij19-Aug-05 2:27

skooij

19-Aug-05 2:27

Great, and then the tables are selected by the index I guess ?

Re: How to pick up multiple resultsets from a query

Guffa19-Aug-05 2:43

Re: important coding problem

19-Aug-05 2:43

Yes.

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important coding problem

snouto19-Aug-05 0:53

snouto

19-Aug-05 0:53

hi dudes;
how are you all ?
when i open my application which is consisting of listbox and button to add values in the listbox but normally when i close the application and reopen it again it gives me new listbox with nothing included inside it that is because every time the application starts the initialize components method create new instance of the listbox that is fine .
but what about if i need to store these values one time and every time i open my application the values still exist ? any help about this the same as the download accelerator as much as the files you download they stored in listbox in the application and if you close the application and reopen it again you can see the values inside the listbox of the downloaded files ? any help to do the same ?
Thanks alot.

Miss With The Best And Die Like The Rest

Corinna John19-Aug-05 1:32

Corinna John

19-Aug-05 1:32

snouto wrote:
need to store these values one time

Store them to a file in the Closing-EventHandler of the form,
read them from the file in the form's Load-EventHandler.

<br />
private void MainForm_Load(object sender, System.EventArgs e) {<br />
ReadInitialValue();<br />
}<br />
<br />
private void MainForm_Closing(object sender, System.EventArgs e) {<br />
SaveInitialValues();<br />
}<br />

_________________________________
Please inform me about my English mistakes, as I'm still trying to learn your language!

Re: important coding problem

miah alom19-Aug-05 4:34

miah alom

19-Aug-05 4:34

check this useful link
http://www.codeproject.com/csharp/PersistentDataStructures.asp

Re: important coding problem

Corinna John19-Aug-05 5:16

Corinna John

19-Aug-05 5:16

Clicketyclick: http://www.codeproject.com/csharp/PersistentDataStructures.asp

_________________________________
Please inform me about my English mistakes, as I'm still trying to learn your language!

Cancel closing a form

bouli19-Aug-05 0:06

bouli

19-Aug-05 0:06

Hello gurus,

I'd like to know how to cancel the Closing event?

I mean, when the user click on the close button of the main window, I ask him if he wants to quit via the MessageBox class. If he answers no or cancel, the window does not close.

Can someone show me a code snippet please?

Thanks for the help.

Best regards.

Fred.

There is no spoon.

Re: Cancel closing a form

Azerax19-Aug-05 1:05

Re: Cancel closing a form

19-Aug-05 1:05

Cancelling the closing of a form is quite simple and can be implemented as follows:

protected void Form1_Cancel (Object sender, CancelEventArgs e) {
if (!myDataIsSaved) {
e.Cancel = true;
MessageBox.Show("You must save first.");
}
else {
e.Cancel = false;
MessageBox.Show("Goodbye.");
}
}

Elvis (a.k.a. Azerax)

Life is Music listen to it before it fades

bouli19-Aug-05 1:19

bouli

19-Aug-05 1:19

ok this works Smile | :)

thanks

There is no spoon.

Cannot get value because it is DBNull

beqs18-Aug-05 23:47

beqs

18-Aug-05 23:47

Hi,

I am using a database. And return the data to a DataSet dsPlayers. Some players have a birthday, which is a DateTime field, and some do not. These have no value so it says <null>. I want to put their birthday to a DateTimePicker dtpBirthday, but when it is <null> I want to give the DateTimePicker the value DateTime.Now.

I have the following code, which is noit working for me.

<br />
if (dsPlayer.Players[0].BirthDay.ToString() == null)<br />
{<br />
dtpBirthday.Value = DateTime.Now;<br />
}<br />
else<br />
{<br />
dtpBirthday.Value = dsPlayer.Players[0].BirthDay;<br />
}<br />

What is the best way to make this if statement?

Guffa18-Aug-05 23:53

18-Aug-05 23:53

You can use the method IsNull of the DataRow class to check if the value in a cell is DBNull.

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Anonymous19-Aug-05 0:39

Anonymous

19-Aug-05 0:39

Okay. I am not know with this. Can you give me an example how to implement this?

Guffa19-Aug-05 0:51

19-Aug-05 0:51

When you read the data from the datatable, I call it playerTable here:

if (playerTable.Rows[index].IsNull["BirthDay"]) {
... store a value that represents 'no data'
} else {
... get the data
}

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Anonymous19-Aug-05 1:31

Anonymous

19-Aug-05 1:31

Thanx Guffa that will do the trick! (y)

Big Grin | :-D

Azerax19-Aug-05 0:50

19-Aug-05 0:50

How about trying this?

dtpBirthday.Value = dsPlayer.Players[0].BirthDay.ToString()== DBNull.Value ? DateTime.Now : dsPlayer.Players[0].BirthDay ;

This is an example of a conditional if statement and will best suit your purpose.

The Conditional Statement

variable = op1 == op2 ? trueValue : FalseValue ;

where:
op1 == op2 is your condition

Life is Music listen to it before it fades away

Anonymous19-Aug-05 1:21

Anonymous

19-Aug-05 1:21

Hi Azerax,

I tried something like that but it gives me the following error:

Operator '==' cannot be applied to operands of type 'string' and 'System.DBNull'

That's why I came to codeproject.

Azerax19-Aug-05 2:37

19-Aug-05 2:37

Ohh I am sorry Frown | :(

Please note the corrected code as follows:

dtpBirthday.Value = dsPlayer.Players[0]["BirthDay"]== DBNull.Value ? DateTime.Now : dsPlayer.Players[0]["Birthday"].ToString() ;

Where birthday is a field in your dataTable.

Elvis (a.k.a Azerax) Cool | :cool:

Life is Music listen to it before it fades

Azerax19-Aug-05 2:41

Re: Boxing/unboxing objects

19-Aug-05 2:41

Ohh I am sorry I got it wrong again . Please note the corrected code as follows:

dtpBirthday.Value = dsPlayer.Tables["Players"].Rows[0]["Birthday"]== DBNull.Value ? DateTime.Now : dsPlayer.Tables["Players"].Rows[0]["Birthday"].ToString() ;

Sorry for the trouble...

Elvis (a.k.a Azerax)

Life is Music listen to it before it fades

Boxing/unboxing objects

JorisFromHolland18-Aug-05 22:08

JorisFromHolland

18-Aug-05 22:08

Hello,

i've got an issue with objects. I have some code which
looks something like this:

public void X(object o) {
Y.getName(o);
}

public class Y {
public static string getName(Relation r) {

}

public static string getName(object o) {

}
}

when in method X i get a Relation object and I use the overloaded static method
in class Y it always uses the overload that accepts the base-object type. Maybe this
is because the object I get in method X kind of 'wraps' the Relation object in a 'base' -object. Does anyone know how I can manage to get this to work ?

Thanks

with kind regards
Joris

Guffa18-Aug-05 22:16