C# beginners question

[susan.f.barrett]

Hi

I'm sure there is a very simple answer to this but it's got me stuck
for hours!

How do you change the properties of parent forms? e.g. if you have a
dialog box that has a textbox on it, when the user clicks an OK Button,
and the value is saved to the database, how do you then update the
treeview on the main parent form?

I'm creating a new instance of the form within the child, which gives
me access to the Nodes but it doesn't allow me to change any thing?

To make things simpler, I tried to change the .Text property of the
parent form within the child form but I can't even seem to do that.

I'm sure I'm missing something really simple!

Thanks for your time
Susan

[Adam Benson]

Hi,

Well I wouldn't really do it that way.

Your parent form needs to check the result of the child dialog and then act
accordingly. As a general rule you wouldn't have a child telling the parent
what to do - well not in my family :-)

So,

parent creates child dialog
child dialog does stuff
parent checks child state and then thinks "OK, I'll change this text, or
light up this button etc."

Hope this general comment helps,

Cheers,

Adam.
<su************ *@googlemail.co m> wrote in message
news:11******** **************@ i40g2000cwc.goo glegroups.com.. .

Hi

I'm sure there is a very simple answer to this but it's got me stuck
for hours!

How do you change the properties of parent forms? e.g. if you have a
dialog box that has a textbox on it, when the user clicks an OK Button,
and the value is saved to the database, how do you then update the
treeview on the main parent form?

I'm creating a new instance of the form within the child, which gives
me access to the Nodes but it doesn't allow me to change any thing?

To make things simpler, I tried to change the .Text property of the
parent form within the child form but I can't even seem to do that.

I'm sure I'm missing something really simple!

Thanks for your time
Susan

[Leon Friesema]

On 28 Feb 2006 04:05:09 -0800, su************* @googlemail.com wrote:

Hi

I'm sure there is a very simple answer to this but it's got me stuck
for hours!

How do you change the properties of parent forms? e.g. if you have a
dialog box that has a textbox on it, when the user clicks an OK Button,
and the value is saved to the database, how do you then update the
treeview on the main parent form?

I'm creating a new instance of the form within the child, which gives
me access to the Nodes but it doesn't allow me to change any thing?

To make things simpler, I tried to change the .Text property of the
parent form within the child form but I can't even seem to do that.

I'm sure I'm missing something really simple!

Thanks for your time
Susan

Susan,

there are multiple ways of doing this, but first things first. When
clicking the OK button you should set the dialogresult of the
dialogbox to DialogResult.Ok (and initially the dialogresult to
cancel)
When you create the form like this:

if (new MyDialog.ShowDi alog() == DialogResult.Ok )
{
// Update treeview
}

You know when the user clicked OK.

You could then reload the entire treeview or (to save time and
resources) ask for the textbox value and update the selectednode.te xt

greetz, Leon.

[Nick Hounsome]

<su************ *@googlemail.co m> wrote in message
news:11******** **************@ i40g2000cwc.goo glegroups.com.. .

Hi

I'm sure there is a very simple answer to this but it's got me stuck
for hours!

How do you change the properties of parent forms? e.g. if you have a
dialog box that has a textbox on it, when the user clicks an OK Button,
and the value is saved to the database, how do you then update the
treeview on the main parent form?

If the dialog is modal then you just update the main form when it returns.

If it is not modal then having an event on the dialog is the cleanest way
forward.

If you think of the dialog as just another sort of control but with rather
more data than a simple control then you can see how to go about things.

Often you'll find that you want to use a something like CancelEventArgs to
allow the main form to veto the action and prevent the dalog from closing.

[susan.f.barrett]

Adan, Leon

Thanks for your quick replies,

Everything suddenly makes so much more sense!

I've changed things around in the way you suggest and it's working
great now. It's such a great feeling to get around this hurdle! =)

Susan

Leon Friesema wrote:

On 28 Feb 2006 04:05:09 -0800, su************* @googlemail.com wrote:

Hi

I'm sure there is a very simple answer to this but it's got me stuck
for hours!

How do you change the properties of parent forms? e.g. if you have a
dialog box that has a textbox on it, when the user clicks an OK Button,
and the value is saved to the database, how do you then update the
treeview on the main parent form?

I'm creating a new instance of the form within the child, which gives
me access to the Nodes but it doesn't allow me to change any thing?

To make things simpler, I tried to change the .Text property of the
parent form within the child form but I can't even seem to do that.

I'm sure I'm missing something really simple!

Thanks for your time
Susan

Susan,

there are multiple ways of doing this, but first things first. When
clicking the OK button you should set the dialogresult of the
dialogbox to DialogResult.Ok (and initially the dialogresult to
cancel)
When you create the form like this:

if (new MyDialog.ShowDi alog() == DialogResult.Ok )
{
// Update treeview
}

You know when the user clicked OK.

You could then reload the entire treeview or (to save time and
resources) ask for the textbox value and update the selectednode.te xt

greetz, Leon.

[susan.f.barrett]

Following on from my original message,

How would i go about retrieving a value from the parent form in the
child?

e.g.
A user right clicks on a TreeView node and selects "Rename..."
A dialog form comes up, but how do I populate a textbox with the
SelectedNode on the parent form?

I've tried this:
StockCategories mainForm = new StockCategories ();
stockCategoryNa me.Text =
mainForm.treeVi ew.SelectedNode .ToString();

But mainForm.treeVi ew.SelectedNode .ToString() is null. I guess I'm
going totally wrong with trying to create "mainForm"?

I also tried calling the child form like this: editStockCatego ry f =
new editStockCatego ry(treeView.Sel ectedNode.Text) ;
and then when declaring the child form I put this: public
editStockCatego ry(string nodeText)

But I'm not sure how to make nodeText available in the child form Load
event.

Arghhh.

Susan

[Leon Friesema]

On 28 Feb 2006 06:19:52 -0800, "su************ *@googlemail.co m"
<su************ *@googlemail.co m> wrote:

Following on from my original message,

How would i go about retrieving a value from the parent form in the
child?

e.g.
A user right clicks on a TreeView node and selects "Rename..."
A dialog form comes up, but how do I populate a textbox with the
SelectedNode on the parent form?

I've tried this:
StockCategories mainForm = new StockCategories ();
stockCategoryNa me.Text =
mainForm.treeV iew.SelectedNod e.ToString();

But mainForm.treeVi ew.SelectedNode .ToString() is null. I guess I'm
going totally wrong with trying to create "mainForm"?

I also tried calling the child form like this: editStockCatego ry f =
new editStockCatego ry(treeView.Sel ectedNode.Text) ;
and then when declaring the child form I put this: public
editStockCateg ory(string nodeText)

But I'm not sure how to make nodeText available in the child form Load
event.

Arghhh.

Susan

The SelectedNode.To String() doesn't return to value for the Text
attribute of the node. Use SelectedNode.Te xt instead.
But first, before doing that, make sure that a node is selected to
prevent errors.

if (MyTreeview.Sel ectedNode != null)
{
... do my stuff

Setting Text is also not correct. The Text attribute for the form is
just the Dialog caption, not the actual textbox. You could try to set
to modifiers of the textbox to internal or public. That way you could
access the textbox using

mainForm.TextBo x1.Text

But I would suggest to create a new property in the code of the form
which uses the textbox like this:
internal string NodeValue
{
get { return Textbox1.Text; }
set { Textbox1.Text = value; }
}

that way you could use
mainForm.NodeVa lue = SelectedNode.Te xt

in total: you create the form like this (based upon the "fact" that
your childform performs a database-update all by itself):

StockCategories mainForm = new StockCategories ();
mainForm.NodeVa lue = MyTreeview.Sele ctedNode.Text
if (mainForm.ShowD ialog() == DialogResult.Ok )
{
MyTreeview.Sele ctedNode.Text = mainForm.NodeVa lue;
}

Besides that, one suggestion, do not use "mainForm" as variable name,
since it is not your mainForm :-)

greetz,
Leon

[Ignacio Machin \( .NET/ C# MVP \)]

HI,

You pass a reference to the parent form to the child form, also you need to
make accesible the controls you want to have access to (either by declaring
them public or by using properties )

Another possible pattern to update one form from other is using a method
that indicate that a changed was performed and the interface (form's
control) need to be reload with updated data. you can do this by declaring
an interface like

public interface IDataUpdated{ void NewDataSaved(); } and having the parent
class implement it, the child could get a reference to that instance and
after the updated call the method.
This approach is more flexible as you can have several child forms and these
forms need not to be modals. (using DialogResult usually imply that the
child form has to be modal)

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

<su************ *@googlemail.co m> wrote in message
news:11******** **************@ i39g2000cwa.goo glegroups.com.. .

Following on from my original message,

How would i go about retrieving a value from the parent form in the
child?

e.g.
A user right clicks on a TreeView node and selects "Rename..."
A dialog form comes up, but how do I populate a textbox with the
SelectedNode on the parent form?

I've tried this:
StockCategories mainForm = new StockCategories ();
stockCategoryNa me.Text =
mainForm.treeVi ew.SelectedNode .ToString();

But mainForm.treeVi ew.SelectedNode .ToString() is null. I guess I'm
going totally wrong with trying to create "mainForm"?

I also tried calling the child form like this: editStockCatego ry f =
new editStockCatego ry(treeView.Sel ectedNode.Text) ;
and then when declaring the child form I put this: public
editStockCatego ry(string nodeText)

But I'm not sure how to make nodeText available in the child form Load
event.

Arghhh.

Susan

[Nick Hounsome]

"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us > wrote
in message news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

HI,

You pass a reference to the parent form to the child form

Then you have created a mutual dependency between the forms. They cannot be
developed, tested or deployed independently.

Use interfaces and/or events.

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

"Nick Hounsome" <nh***@nickhoun some.me.uk> wrote in message
news:qD******** **********@fe3. news.blueyonder .co.uk...

"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us >
wrote in message news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

HI,

You pass a reference to the parent form to the child form

Then you have created a mutual dependency between the forms. They cannot
be developed, tested or deployed independently.

Use interfaces and/or events.

True, you create a dependency, the best way is th use an interface that
expose only the needed public data member that you need


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