Array of Textboxes

[garak]

Hi,

can anyone tell me what ist wrong with this code ?

TextBox[] txtField = new TextBox[4];
txtField[0].Text = "Hello";

I get the error :
An unhandled exception of type 'System.NullReferenceException'
occurred in PentaEngine.exe

Additional information: Object reference not set to an instance of an
object.
Thank you very much for you help.
Frank
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[Marco A. Sánchez]

This code initializes the array object, but does not initialize the array elements

TextBox[] txtField = new TextBox[4]
That is, when you tries to set the property value, the object txtField[0] doesn't exist, it's a null reference
txtField[0].Text = "Hello"

You must create the objects before using it. For example
txtField[0] = new TextBox()

[Sheila Jones]

Hello Frank,

You haven't actually created any TextBox objects, you've only created a
4-element TextBox array with each element initialised to null. You need to
assign a valid TextBox reference to the array elements, e.g.
txtField[0] = new TextBox();
etc.

I hope that helps.
"garak" <fp*******@gmx-dot-de.no-spam.invalid> wrote in message
news:40********@Usenet.com...

Hi,

can anyone tell me what ist wrong with this code ?

TextBox[] txtField = new TextBox[4];
txtField[0].Text = "Hello";

I get the error :
An unhandled exception of type 'System.NullReferenceException'
occurred in PentaEngine.exe

Additional information: Object reference not set to an instance of an
object.
Thank you very much for you help.
Frank
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[Jon Skeet [C# MVP]]

garak <fp*******@gmx-dot-de.no-spam.invalid> wrote:

can anyone tell me what ist wrong with this code ?

TextBox[] txtField = new TextBox[4];
That creates an array which can hold 4 TextBox references. It doesn't
create any actual TextBoxes. Each element in the array is null.
txtField[0].Text = "Hello";

That then dereferences the null to try to set the Text property - and
fails.

You need to do something like:

TextBox[] txtField = new TextBox[4];
for (int i=0; i < txtField.Length; i++)
{
txtField[i] = new TextBox();
}
txtField[0].Text = "Hello";

(Note that this is not limited to TextBoxes - it's common to all arrays
of reference types.)

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[garak]

Yeah thats right...
Thank you very much - you saved my day
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[garak]

Yeah thats right...
Thank you very much - you saved my day
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