Re: Controls across forms? - C# Discussion Boards

Re: TreeView Expansion Question

23-Apr-02 17:43

If you knew this path at compile time then you may just want to hold onto a reference to the TreeNode object when you created it so it will be handy.

The alternative is to just drill down on the Nodes collection to get to it; again, if you knew where you put it at compile time.

If the revelation of it became known at runtime, i.e. it was passed in on an event, just call the Remove method on the node itself.

Yet another method would to mark special nodes by putting something in the Tag property, you could then enumerate the entire tree and pluck out the nodes your after.

Does this answer the question?

Sabran27-Apr-02 0:18

Sabran

27-Apr-02 0:18

Thanks for your help. Unfortunately, the tree is constructed and used for another purpose before I want to deal with opening it up to a specific directory. I took your advice, however. After I developed the tree, I ended up just enumerating through it until the path specified by the user was the same as one of the node's full name. I think what I was looking for was a method for the TreeView to automatically return a node given a path. Like:

TreeNode returnNode(string path)

which would ideally return the node whose fullName matched "path" (or null if no match could be found). Which actually happens the function I ended up implementing. Anyway, thanks for the help.

- Sabran

Re: TreeView Expansion Question

Neil Van Note27-Apr-02 8:42

27-Apr-02 8:42

When you see the PathSeparator property of TreeView and the FullPath property of TreeNode, It would leave you to believe that it also has a built-in searching mechanism that utilizes these. If it does, I have not found it.

Regards

Controls across forms?

Brian Olej23-Apr-02 7:19

Brian Olej

23-Apr-02 7:19

Hello everyone!,
I've lingered code project reading posts etc for a quite a while (say 3-4 months). Im proud to say I am now part of the community.

Ok now for my first question: Recently i have decided to mess around a little with .net so i have made an app, a MDI app. I have 3 different forms inside it as child windows. How would it be possible to exchange data across the forms(I.E. Click a button on one form have my app retreive a string from a text box on another and add the string into a list box on the third)? I am capable of doing each of thoes if it was on one form but im unware to how I would make the three Forms communicate. I hope you can understand my question, if not let me know i will gladly rephrase it so that it may possibly be understandable. Smile | :)

James T. Johnson23-Apr-02 8:31

James T. Johnson

23-Apr-02 8:31

brian1415 wrote:
Im proud to say I am now part of the community.

Welcome Smile | :)

I can think of a couple different options, both require the child forms to be aware of the parent. The first one is the best though and I'll explain how to do it.

The first has the child forms knowing only about itself and the parent. When data needs to be exchanged it tells the Parent form to do it.

The second requires the child forms to know about the parent and the other child windows. This can make maintenance a nightmare but opens the door up a bit for what you want to do.

Assume the parent form is of type ParentForm. Then to get a reference to the parent from the child you would do ParentForm p = this.Parent as ParentForm.

Now that you have a reference to the ParentForm you can call methods on it... When you want to pass data around you tell the parent to pass the data by calling a method on it. That method tells the other child window what to do. The ParentForm is aware of all child windows.

Difficult for me to explain in English, but pretty easy to do in code Smile | :)

James

Simplicity Rules!

Brian Olej23-Apr-02 9:27

Brian Olej

23-Apr-02 9:27

Hello thank you for the help!, but I've been fiddling around with my app trying to do what you suggested but im not sure if I understand Confused | :confused:

... I know you are probably busy but if it would not be to much trouble could you possibly post/Email me a quick code snippet so that I may understand? My knoledge of WinForms is very limited.
Thank you once again... Smile | :)

James T. Johnson24-Apr-02 2:10

James T. Johnson

24-Apr-02 2:10

Heres the names I will use.

Classes

ParentForm - The MDI Parent
ChildFormA - One of the child forms
ChildFormB - Another child form
ChildFormC - The last child form
DataA - Data class for ChildFormA
DataB - Data class for ChildFormB
DataC - Data class for ChildFormC

Class instances stored in ParentForm class

childA - ChildFormA
childB - ChildFormB
childC - ChildFormC

Now a little setup Smile | :)

In ParentForm

public void SendToChildA(DataA data)
{
  childA.Data = data;
  childA.DataSent();
}

Do similar for the other children (B and C)

Now in each of the ChildForms create a Data property which is of the same type as the class associated with it. Also create a method called DataSent which will actually do the processing of the data for the child form.

Now when you want to send data from one child form to another you call the appropriate method on the parent.

....
// Going to send data to ChildFormB
ParentForm parent = this.Parent as ParentForm;
 
DataB data = new DataB();
// fill out data class
 
parent.SendToChildB(data);
....

If you wanted to truly adopt .NET practices you would replace the DataSent method and Data properties on the client with events; but for a quick example this works. I'll leave switching to an event as an exercise for you, its not too difficult Smile | :)

HTH,

James

Simplicity Rules!

Brian Olej24-Apr-02 2:31

Brian Olej

24-Apr-02 2:31

Thank you very much I apreciate you help! Big Grin | :-D

Hit Test

23-Apr-02 6:47

Anyone know how to find the control I am currently over without cycling through each one?

ie. Control ctrl = this.hittest(x,y);

cant find hit test anywhere.

thanks

Re: Hit Test

Nick Parker23-Apr-02 8:00

Nick Parker

23-Apr-02 8:00

Check something like this:

protected override void OnMouseOver(System.Windows.Form.MouseEventArgs mea)
{
mea.<code>[SomeMethod()]</code>
}

Sorry, not at home(with .NET Framework) to check the exact value, hope this will lead you in the right direction.

Nick Parker

J

This is a non-Calculus course as long as you know things like line integrals and surface integrals...

Re: Hit Test

Neil Van Note23-Apr-02 8:04

Re: GetChildAtPoint *ADVANCED!*

23-Apr-02 8:04

GetChildAtPoint

23-Apr-02 9:36

Thanks, GetChildAtPoint() works perfectly.. except for these two problems:

1) it takes relative x and y to that control's clientarea. so this.GetChildAtPoint(10,10) is very different from txtBlah.GetChildAtPoint(10,10)... which leads to my next problem:

2) get child only gets one child down. I would rather have this.GetChildAtPoint(x,y) get the control inside of the groupbox at x,y and not the groupbox. code to get only the second layer looks like this:

Control m_ctrl = this.GetChildAtPoint(new System.Drawing.Point( e.X, e.Y));<br />
// check if !null then...<br />
Control m_subCtrl = m_ctrl.GetChildAtPoint(new System.Drawing.Point( e.X - m_ctrl.Left, e.Y - m_ctrl.Top ));<br />
//...

any ideas (without recursion, please Smile | :)

)

Re: GetChildAtPoint *ADVANCED!*

Neil Van Note23-Apr-02 10:10

Re: GetChildAtPoint *ADVANCED!*

23-Apr-02 10:10

Point pt		= new Point(x, y);
Control parent	= this;
Control child	= parent.GetChildAtPoint(pt);
while (null != child)
{
	pt = parent.PointToScreen(pt);
	pt = child.PointToClient(pt);
	parent = child;
	child = parent.GetChildAtPoint(pt);
}
// parent now contains the control at x,y

BTW, If there is a functional equiv. to the MapWindowPoints API, I am all ears...

Neil Van Note23-Apr-02 18:29

23-Apr-02 18:29

A slight improvement to reduce the number of point mappings...

Point pt		= new Point(x, y);
Control parent	= this;
Control child	= parent.GetChildAtPoint(pt);
if (null != child)
{
	pt = parent.PointToScreen(pt);
	do
	{
		parent = child;
		child = parent.GetChildAtPoint(parent.PointToClient(pt));
	} while (null != child);
}
// parent now contains the control at x,y

A deeper explaination

23-Apr-02 9:49

if (c_urwondering)<br />
{

I have a form with three tabs in a tabcontrol and many controls inside each tab. even controls inside groupboxes in each tab. many.

this form represents a scrollable row in a recordset. it has a vertical scrollbar on the right.

I attach:
this.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.Dialog_MouseWheel);

i want to only allow scrolling when the mouse is not on data driven controls. so scroll when over a label, but not a combobox; inside a groupbox, but not inside a checkbox in a groupbox. etc

}

ConectionStringIII

Mazdak23-Apr-02 5:03

Mazdak

23-Apr-02 5:03

I use this connection string to connect to database:

connString=@"Provider=Microsoft.Jet.OLEDB.4.0;User ID=Admin;Password=mypass;Data Source=..\..\Tennis.mdb;Jet OLEDB:System Database=E:\Program Files\Microsoft Office\Office\System.mdw" ;

but ecxeption thrown:

---------------------------

---------------------------
System.Data.OleDb.OleDbException: Not a valid account name or password.

at System.Data.OleDb.OleDbConnection.ProcessResults(Int32 hr)

at System.Data.OleDb.OleDbConnection.InitializeProvider()

at System.Data.OleDb.OleDbConnection.Open()

at Tennis.MainForm..ctor() in f:\visual studio projects\projectc#\tennis\mainform1.cs:line 65
---------------------------
OK
---------------------------

Any suggestion?!!! Cry | :((

Mazy

"The path you tread is narrow and the drop is shear and very high,
The ravens all are watching from a vantage point near by,
Apprehension creeping like a choo-train uo your spine,
Will the tightrope reach the end;will the final cuplet rhyme?"Cymbaline-Pink Floyd

Neil Van Note23-Apr-02 8:31

23-Apr-02 8:31

1. All of the examples I have seen using "System database=" spell it with a lower-case "database" as in "System database=" not "System Database=". I really don't know if this matters or not.

2. Are you using a general password protected database, or a user-level secure database? If you are using a general password protected database, the connection string magic is ";Database Password=mypass;".

Regards

Neil Van Note23-Apr-02 8:39

23-Apr-02 8:39

Scratch #1, I eliminated it as a potential problem...

Mazdak23-Apr-02 19:12

Mazdak

23-Apr-02 19:12

Thanks Neil,
The Magic WAS the ";Database Password=password;" (with a ;Jet OLEDB Smile | :)

before it

I feel relifed.

Mazy

"The path you tread is narrow and the drop is shear and very high,
The ravens all are watching from a vantage point near by,
Apprehension creeping like a choo-train uo your spine,
Will the tightrope reach the end;will the final cuplet rhyme?"Cymbaline-Pink Floyd

Neil Van Note23-Apr-02 19:20