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Hello,
I am trying to write a strongly typed object class
(so I can bind the properties of the class object to form controls) along the lines of:
Public Class foo
Private _myCol As Collection
Public Property Name() As String
Get
Return _myCol("Name")
End Get
Set(ByVal value As String)
_myCol.Remove("Name")
_myCol.Add(value, "Name")
End Set
End Property
Public Property Title() As String
Get
Return _myCol("Title")
End Get
Set(ByVal value As String)
_myCol.Remove("Title")
_myCol.Add(value, "Title")
End Set
End Property
End Class
This is quite simply awful. If I use an array instead of a collection I can get rid of the
collection remove and add rubbish.
In effect I could replace
Return _myCol("Title")
with
Return _myArray(1)
This means that I have to relate each property to an index (Name to 1 and Title to 2 for example)
and it means that when I create the class I have to manually type this relationship in.
The real problem with this is that I anticpate having lots of classes like this each with lots
of properties and frankly I am a bit lazy and dont want to physically key them in like this.
One option was to bind the controls to an exposed dataset in my foo class instead but I dont
want to do that. I want to expose Foo.Name and Foo.Title etc.
There must be an easier way than that above - any ideas?? (either a template based way of entering
them into visual studio or a completly new way of coding them)
thanks in advance
Martin
-- modified at 5:25 Wednesday 27th June, 2007
life is a bowl of cherries
go on take a byte
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Why don't you create a structure with the properties you like, i.e.
<code>
Class _MyProperies
Public Title, Name, etc As String
End Class
</code>
And then in your foo class define an array of this type
Private _MyArray As _MyProperties()
Does this help you?
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Hi,
thanks for that but it doesnt really
my foo properties woud be
Public Property Name ...
get ..
return _Myarry(Index)
....
so for each property I would need to key in name and the index in a couple of places
I was hoping to avoid that for 2 reasons
1.. I dont like saying property Name is Index 1 in the _MyArray - Its just ugly
2.. I am lazy and dont like keying in Name and index for every property in every class
any other ideas??
thanks
Martin
life is a bowl of cherries
go on take a byte
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Private C As New Collection<br />
Property MyProperties(ByVal i As String) As String<br />
Get<br />
Return C(i)<br />
End Get<br />
Set(ByVal value As String)<br />
Try<br />
C.Remove(i)<br />
Catch ex As Exception<br />
Finally<br />
C.Add(value, i)<br />
End Try<br />
End Set<br />
End Property
A.E.K
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Hi,
Thanks for that but any code using foo class would have to do
foo.MyProperties("Name") = "John"
I absolutley need the outside world to see it as strongly typed properties
such as Foo.Name and Foo.Type.
This is because the classes will be used as business objects and I may wish
to add extra code to one or two of a classes properties later on . I dont want a big case statement in the properties code (or indeed a function called by the properties code).
thanks anyway
Martin
life is a bowl of cherries
go on take a byte
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In that case, you could do two classes. One for an instance of the object that holds all the properties and a second as a collection of those objects. The .NET Framework uses a setup like this extensively.
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Sorry dave,
I'm not quite following how that would work
can you give me a snippet
I dont see how it makes adifference if its one Foo object or a collection of foo objects. Foo.Name still needs to get to a varaible or internal collection
I have just been reading up on intellisense code snippets that is in effect a template for my class and that may help
thanks
Martin
life is a bowl of cherries
go on take a byte
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For the Person:
Public Class Person
Private _Name As String
Private _Title As String
Public Property Name As String
...
Public Property Title As String
...
End Class
For the Collection of Persons (simplified)
Public Class PersonsCollection
Implements IList, ICollection, IEnumerable
Private Persons As Person()
Private PersonsCount As Integer
Public Sub New()
End Sub
Public Overridable Sub Add(ByVal person As Person)
...
End Sub
...
End Class
Of course, in 2005, you can skip the collection and just use a typed collection instead:
Dim Persons As New List(Of Person)
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Hi
my problem is in here
Public Class Person
Private _Name As String
Private _Title As String
Public Property Name As String
get
return _name
set (value..)
_name = value
In this property I have enterd Name once and _Name twice.
now this is fine for one or two properties but when you have 80 of these properties in a class and you need to create many classes then typing it in becomes painfull.
I think the code snippet will help but I was hoping for some kind of generator where
I could key in a list and have a class created for me with those properties set from the list.
End Class
thanks
Martin
life is a bowl of cherries
go on take a byte
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MartyK2007 wrote: In this property I have enterd Name once and _Name twice.
now this is fine for one or two properties but when you have 80 of these properties in a class and you need to create many classes then typing it in becomes painfull.
A generator or two might exist, but I don't know of any. Try Googling for "VB.NET Property code generation".
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Write another program that gets the name of the properties ,adds them to a list and finally makes the code for you to add to your class.
The function below may help you
Function Generate(ByVal mc As Collection) As String
Dim str As String
For i As Integer = 1 To mc.Count
str &= "Public Property " & mc(i) & "() As String" * vbCrLf & _
"Get" & vbCrLf & "Return MyDataCol(""" & mc(i) & """)" & vbCrLf & _
"End Get" & vbCrLf & "Set(ByVal value As String)" & vbCrLf & _
"MyDataCol.Remove(""" & mc(i) & """)" & vbCrLf & "MyDataCol.Add(value, """ & mc(i) & """)" & _
vbCrLf & "End Set" & vbCrLf & "End Property" & vbCrLf
Next
Return str
End Function
where mc is a collection of property names
A.E.K
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Nah. I hate copy and paste coding and refuse to use such a technique in an addin. I'd much rather have the addin write, and if need be, rewrite the property code for me, directly in the CodeDom, when I change the member variables.
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you can rewrite the property??
Is this a special VB way or "Just" writing a program to read in the .vb file and change it then save the new file overwriting the old one??
thanks
Martin
life is a bowl of cherries
go on take a byte
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No. This would be a VS AddIn (not for Express though!) that manipulates the document object model that is your code, otherwise know as CodeDom. Search for that term on MSDN and you'll come up with all kinds of information.
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wow I never knew that existed
NET is getting bigger and bigger - sigh - brain overload!!
Thanks for that - very interesting
Martin
life is a bowl of cherries
go on take a byte
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Are you using .net 1.1 or 2.0? If you are using 2.0 you can use generics
Public Class MyProperties
Public Property1 as string
Public Property2 as string
End Class
Dim list as new list(of myproperties)
You then then access the properies in a strongly-typed way
Dim name as string = list(0).MyProperty1
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hi,
I am on version 2
I think this is the same as the array solution
it would look something like
public property Name as string
get
return list(0).Myproperty1
..........etc
I need to relate property Name to Index position 0 in this case.
In my current development I will need about 30 of these clases averaging 20 of these properties per class. The worst class will have 80 or so properties.
I am really looking for something like
public property Name as string
get
return <obj>("Name") 'where <obj> is some classed object
...............
I could use collection but writing back changes is upgly (removing the item then adding it again - yuk)
I could use arrayLists as in return ArrayList.BinarySearch("Name") but I have to keep
the arraylist sorted and am wondering how fast the binarysearch will be compared
to the collection name index. Although knowing microsoft its probably the same code.
and then I am looking for some quick n painless way to actually type in these classes into visual studio.
Thanks
Martin
life is a bowl of cherries
go on take a byte
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Hello
How to get colored area in the center (from the top and all way down) of page. I have tables (centered) on the page. Now I want to get the colored area that covers always the whole page center (10px wider than a table) area but all way down even if the table is on the top part of the page. I am doing a home page with vb.net.
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<table bgcolor="yellow">
........
When you get mad...THINK twice that the only advice
Tamimi - Code
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but how to make colored area to go all the way down in the center of the page. If someone use different resolution then the my table is in upper part of page and the coloured area should continue all the way down.
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[
DLLImport("ODBCCP32.dll")
]
private static extern bool SQLConfigDataSource(
IntPtr parent, int request, string driver, string attributes)
this was the code in C#
what is the equivalant in vb.net 2005
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www.pinvoke.net[^] is a good place to find p/invoke signatures. Or there are online sites that convert small snippets between the two languages.
Christian Graus - Microsoft MVP - C++
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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please give me some code or sample on how to make a button on a datagrid cell. thnx!
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hi,
you can make a button on datagridview very easily at desigen time.
when you add a column to datagridview , change its type to DatagridViewButtonColumn.
if you want to add column at run time then use following code
Dim ColumnButton As New DataGridViewButtonColumn<br />
columnButton.headertext="Your Heading"<br />
DataGridView1.Columns.Add(columnButton)
Hope this helps
Rupesh Kumar Swami
Software Engineer,
Integrated Solution,
Bikaner (India)
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