Paul,
All agreed there. The point I was trying to make was that the Databinding is
difficult to implement as a "two way" binding unless you know about adding
a PropertyChangedEventHandler to your class.
I do it slightly different in that I can track for variousl update "Modes"by
adding an Enum to the class:
// Enum for changed states
public enum EntityStateEnum
{
Unchanged,
Added,
Deleted,
Modified,
}
// Custom Method to handle Entity State
public EntityStateEnum EntityState
{
get { return _EntityState; }
private set { _EntityState = value; }
}
...and then a Datastate Changed Method handler:
//
private void DataStateChange(EntityStateEnum dataState, string propertyName)
{
// Raise the event
if (PropertyChanged != null && propertyName != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
// If the state is deleted, mark it as deleted
if (dataState == EntityStateEnum.Deleted)
{
this.EntityState = dataState;
}
if (this.EntityState == EntityStateEnum.Unchanged)
{
this.EntityState = dataState;
}
}
Then, in the property get/set:
// Example get/set for object property
private int _nBalance ;
public int nBalance
{
get { return _nBalance; }
set { if( value != nBalance)
{
this.DataStateChange(EntityStateEnum.Modified, "nBalance");
_nBalance = value;
}
}
}
Basically though, the same methodology as yourself but with a little more
control.
All in all though, it isn't easy to find these things out when you are
starting out as we just take 2 way data binding as a standard feature in
VFP.
Dave Crozier
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Paul Hill
Sent: 06 October 2008 13:34
To: ProFox Email List
Subject: Re: [NF] VB.Net Questions
On Mon, Oct 6, 2008 at 9:43 AM, Dave Crozier <[EMAIL PROTECTED]> wrote:
> John,
> I concur with the other group comments but would suggest that you
seriously
> look at C# as opposed to VB.Net.
Agreed. Although I'm still starting out with .NET there seems to be
much more information out there on C# than VB.
> The execution speed is much superior and the OOP things you can do bear
more of a similarity to VFP than VB.
Is the speed really different? I thought C# and VB were the same
language with different 'layouts'.
> My comments, so far, apart from the changed language syntax, having
written
> some 20-30 C# applications are as follows:
>
> Pro:
> 1. My main gripe - Data Binding of Objects to UI classes are a pain in
> VS2005 unless you bind to a Datasource (VFP Cursor equivalent). You can
bind
> an object property quite easily to a textbox for example but the
> relationship is one way only i.e changing the Control u[dates the object
> property but NOT Vice versa without a lot of messing about. This has been
> improved in VS2008 but is still nowhere as easy as in VFP. There is no
> concept of "Controlsource" as we VFPer's know it.
As I said, I'm still toying with .NET but I managed to bind objects to
gui elements fairly easily by implementing the INotifyPropertyChanged
interface.
My object has get/set methods like this:
private string _name;
public string name
{
get { return this._name; }
set { this._name = value; NotifyPropertyChanged("name"); }
}
A change to the object automatically updates the textbox etc.
> 5. I still can't get used to using a "==" as opposed to a "=" in an if
> statement and having to use != as opposed to <>. These still screw me up
all
> the time. One other construct that is a pain is the VFP "Do Case"
equivalent
> i.e Switch. You can forget about putting in case <....> statements that
> refer to any variable/function as you have to reference the variable(s)
> specified in the initial "Switch" statement.
I come from a C background so that's fine by me :-)
Currently I'm struggling with the fact that ASP.NET only supports
'connectionless' data. The idea is that you connect to the database,
get your data and disconnect. The problem
--
Paul
[excessive quoting removed by server]
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