DataGridView inheritance

  • Thread starter Thread starter Nick Locke
  • Start date Start date
N

Nick Locke

I have just found that there is a feature in VS .NET which deliberately
stops me making a DGV "protected" in an ancestor class and then modifying
its properties in inherited classes. I can see why this problematic for MS
and therefore why it has not been implemented. However, I could do with a
suggestion on how best to move forwards with what I need to do.....

I have an ancestor UserControl which contains a single DGV and lots of
methods/properties to allow me to "talk" with that DGV from a containing
form.

I then need around 30 UserControls inherited from that ancestor. They all
need to offer the same methods/properties, but will need different data
connections from their instance of the DGV. They will also need different
columns displayed, with different headings and so on.

I could obviously bin the OO approach altogether and just copy my control 30
times - but I am fearful of then needing to make every change 30 times in
the future.

Suggestions please!

Thanks, Nick.
 
Thinking of one way for myself (maybe). Would it make sense to "paint" each
DGV separately (eg on a form)and then paste the code from the designer into
my inherited class somewhere?
 
You don't have to inherit a DataGridView to create a new class. You can
create a container class that implements and exposes a DataGridView.

--
HTH,

Kevin Spencer
Microsoft MVP

Printing Components, Email Components,
FTP Client Classes, Enhanced Data Controls, much more.
DSI PrintManager, Miradyne Component Libraries:
http://www.miradyne.net
 
Kevin said:
You don't have to inherit a DataGridView to create a new class. You can
create a container class that implements and exposes a DataGridView.
Click to expand...

Kevin, if I am understanding correctly, you are saying that I don't need to
create a User Control, put a DGV on it and then use that as an ancestor
class for all of my objects. Rather, I think you are suggesting that I
create a customised DGV (encapsulating all of my functionality) and then I
just plonk one of those onto each of my target user controls and/or forms.
Am I on the right wavelength?

So, to "create a container class that implements and exposes a
DataGridView", I was hoping that when I did this:

Public Class CustomDGV
Implements System.Windows.Forms.?????

End Class

I would just be able to implement a DGV like that. I am showing my
ignorance here, but need a bit more of a pointer.

Thanks,

Nick
 
Have I answered my own question - is it just:

Public Class CustomDGV

Inherits System.Windows.Forms.DataGridView

End Class

Thanks?!
 
That is one solution. The other is to create a class that implements and
exposes a DataGridView, such as the following (forgive my C#):

public class DataGridViewContainer : UserControl
{
private DataGridView _View;

public int ViewWidth
{
get { return _View.Width; }
set { _View.Width = value; }
}

public DataGridView View { get { return _View; } }
// etc.
}

--
HTH,

Kevin Spencer
Microsoft MVP

Printing Components, Email Components,
FTP Client Classes, Enhanced Data Controls, much more.
DSI PrintManager, Miradyne Component Libraries:
http://www.miradyne.net
 
Nick said:
Public Class CustomDGV
Inherits System.Windows.Forms.DataGridView

overriden and/or additional functions, methods, events etc

End Class
Click to expand...


Kevin said:
That is one solution. The other is to create a class that implements and
exposes a DataGridView, such as the following (forgive my C#):

public class DataGridViewContainer : UserControl
{
private DataGridView _View;

public int ViewWidth
{
get { return _View.Width; }
set { _View.Width = value; }
}

public DataGridView View { get { return _View; } }
// etc.
}
Click to expand...

Thanks Kevin, that certainly does help. Any views (from Kevin or anyone),
whether there are reasons to choose one approach over the other (hidden
gotchas, etc)?

Thanks
 
When you implement a DataGridView rather than inheriting it, you have more
control over what is exposed and what is not. That's about the only
advantage I can think of.

--
HTH,

Kevin Spencer
Microsoft MVP

Printing Components, Email Components,
FTP Client Classes, Enhanced Data Controls, much more.
DSI PrintManager, Miradyne Component Libraries:
http://www.miradyne.net
 
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