Hi everybody

I declared a private static array of textboxes at the top of a class,

then i generate the array elements (new textbox()) in a separate
function (private void in the same class),

then i try to call these elements from another function in the same
class (protected void)

and that causes a nullreference exception. Can anybody tell me what
i'm doing wrong?

Thnx!

Jan

"jan82" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi everybody
>
> I declared a private static array of textboxes at the top of a class,
>
> then i generate the array elements (new textbox()) in a separate
> function (private void in the same class),
>
> then i try to call these elements from another function in the same
> class (protected void)
>
> and that causes a nullreference exception. Can anybody tell me what
> i'm doing wrong?

Either the function hasn't been called or something set the array back to
null.

Or maybe you are expecting the new TextBox[] to create textboxes? All it
does it create an array of nulls, you need to create each textbox
individually.

>
> Thnx!
>
> Jan
>

Michael C schreef:

> "jan82" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Hi everybody
> >
> > I declared a private static array of textboxes at the top of a class,
> >
> > then i generate the array elements (new textbox()) in a separate
> > function (private void in the same class),
> >
> > then i try to call these elements from another function in the same
> > class (protected void)
> >
> > and that causes a nullreference exception. Can anybody tell me what
> > i'm doing wrong?
>
> Either the function hasn't been called or something set the array back to
> null.
>
> Or maybe you are expecting the new TextBox[] to create textboxes? All it
> does it create an array of nulls, you need to create each textbox
> individually.

I create each textbox individually, and I show them on the screen, so
they are created. Then when trying to get the "text" property of these
textboxes from another function (in the same class), I get the error.

Don't you forget to Add the TextBoxes you create in the Array ?

TextBox Mt1 = new TextBox();
TextBox Mt2 = new TextBox();
//Create Array and Add the TextBox's
TextBox[] MyArray = new TextBox[] { Mt1, Mt2 };


"jan82" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...

>
> Michael C schreef:
>
> > "jan82" <(E-Mail Removed)> wrote in message
> > news:(E-Mail Removed)...
> > > Hi everybody
> > >
> > > I declared a private static array of textboxes at the top of a class,
> > >
> > > then i generate the array elements (new textbox()) in a separate
> > > function (private void in the same class),
> > >
> > > then i try to call these elements from another function in the same
> > > class (protected void)
> > >
> > > and that causes a nullreference exception. Can anybody tell me what
> > > i'm doing wrong?
> >
> > Either the function hasn't been called or something set the array back
to
> > null.
> >
> > Or maybe you are expecting the new TextBox[] to create textboxes? All it
> > does it create an array of nulls, you need to create each textbox
> > individually.
>
> I create each textbox individually, and I show them on the screen, so
> they are created. Then when trying to get the "text" property of these
> textboxes from another function (in the same class), I get the error.
>

I do it this way:

private static TextBox[] orderCTNTextBox;

private void buildTable()
{
while (blahblah)
{
orderCTNTextBox[i] = new TextBox(); //i is a counter
orderCTNTextBox[i].Text = "blah blah";
}
}

protected void btnSave_Click(object sender, EventArgs e)
{
for(blahblah)
{
somevar = orderCTNTextBox[i].Text; //and here it goes
wrong...
}
}

TheSteph schreef:

> Don't you forget to Add the TextBoxes you create in the Array ?
>
> TextBox Mt1 = new TextBox();
> TextBox Mt2 = new TextBox();
> //Create Array and Add the TextBox's
> TextBox[] MyArray = new TextBox[] { Mt1, Mt2 };
>
>
> "jan82" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>
> >
> > Michael C schreef:
> >
> > > "jan82" <(E-Mail Removed)> wrote in message
> > > news:(E-Mail Removed)...
> > > > Hi everybody
> > > >
> > > > I declared a private static array of textboxes at the top of a class,
> > > >
> > > > then i generate the array elements (new textbox()) in a separate
> > > > function (private void in the same class),
> > > >
> > > > then i try to call these elements from another function in the same
> > > > class (protected void)
> > > >
> > > > and that causes a nullreference exception. Can anybody tell me what
> > > > i'm doing wrong?
> > >
> > > Either the function hasn't been called or something set the array back
> to
> > > null.
> > >
> > > Or maybe you are expecting the new TextBox[] to create textboxes? All it
> > > does it create an array of nulls, you need to create each textbox
> > > individually.
> >
> > I create each textbox individually, and I show them on the screen, so
> > they are created. Then when trying to get the "text" property of these
> > textboxes from another function (in the same class), I get the error.
> >

Hi Jan,

I came across something similar to this with a static array where it was
being reset to its initialised state after it had been previously
referenced.

Initialising the array in a static constructor rather than in the array's
declaration solved the problem I was experiencing. Maybe someone with more
indepth knowledge can explain why, but this may be the solution whatever the
reason.

HTH, Chris


"jan82" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi everybody
>
> I declared a private static array of textboxes at the top of a class,
>
> then i generate the array elements (new textbox()) in a separate
> function (private void in the same class),
>
> then i try to call these elements from another function in the same
> class (protected void)
>
> and that causes a nullreference exception. Can anybody tell me what
> i'm doing wrong?
>
> Thnx!
>
> Jan
>

Hi,


"jan82" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi everybody
>
> I declared a private static array of textboxes at the top of a class,

Are you sure this is the best way?
A textbox (in a window form) is an instance component. All the instances of
that forms ahve their own instances of textboxes.

Not a good idea have it static!

Why are you doing this?


--
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

Hi,

"jan82" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I do it this way:
>
> private static TextBox[] orderCTNTextBox;
>
> private void buildTable()
> {
> while (blahblah)
> {
> orderCTNTextBox[i] = new TextBox(); //i is a counter
> orderCTNTextBox[i].Text = "blah blah";
> }
> }

Are you inserting this textboxes in the Controls collection of the page?


> protected void btnSave_Click(object sender, EventArgs e)
> {
> for(blahblah)
> {
> somevar = orderCTNTextBox[i].Text; //and here it goes
> wrong...
> }
> }

What is the value of i ?
why dont you modify the code to something like

while( i < orderCTNTextBox.Length)
somevar = orderCTNTextBox[i++].Text;



--
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

Can you show where and how you create the array?

jan82 wrote:
> I do it this way:
>
> private static TextBox[] orderCTNTextBox;

> private void buildTable()
> {
> while (blahblah)
> {
> orderCTNTextBox[i] = new TextBox(); //i is a counter
> orderCTNTextBox[i].Text = "blah blah";
> }
> }
>
> protected void btnSave_Click(object sender, EventArgs e)
> {
> for(blahblah)
> {
> somevar = orderCTNTextBox[i].Text; //and here it goes
> wrong...
> }
> }

Sericinus hunter <(E-Mail Removed)> wrote:
> Can you show where and how you create the array?

Yes, and why is the array static? Multiple instances of that class will reset
the same array if it is a static scope.

--
Thomas T. Veldhouse
Key Fingerprint: 2DB9 813F F510 82C2 E1AE 34D0 D69D 1EDC D5EC AED1