I have an object with two properties 'ABC' and 'ABCField'. When this object is passed to an .NET application (.NET 3.5 CF) via a WebService a Reference.vb object is created on the client which declares the properties which access variables with the same name + 'Field'.
As a result I get
Error 2 'abcField' is already declared as 'Private aBCField As
ABCOption' in this class.
'''<remarks/>
Public Property ABC() As ABCOption
Get
Return Me.aBCField
End Get
Set
Me.aBCField = value
End Set
End Property
'''<remarks/>
Public Property ABCField() As String
Get
Return Me.aBCFieldField
End Get
Set
Me.aBCFieldField = value
End Set
End Property
For compatibility reasons I would prefer not to rename or remove the properties in this object.
Is there a way arround this? Is there an attribute which can be set to change the name of the property as it is sent over the Web Service?
Its funny how once you submit a question inspiration strikes.
I have used the Xml.Serialization.XmlIgnore() attribute in the object on the service side to hide the property 'ABC' from the client and created a new property called 'ABCProxy' property which gets and sets 'ABC'.
Related
I’m building an Access database with classes e.g clsOrder, clsCustomer etc which manage the interface with tables. These classes create instances of forms when displaying their data. I found that once the execution of code was within one of these forms I couldn’t refer to the parent object that created it (so is there a better way of doing this? would be part of my question).
To deal with this I’m using a scripting dictionary to store instances of classes with a key using the ID of the class and a unique identifier for the class (e.g Order-3265). I then store a reference to the owner object in the form itself.
So when an object is created and its ID is known it puts a pointer to itself in the dictionary and gives that pointer to its form (hope that’s clear enough).
This then allows the form to interact with its owner class.
I’m using another class clsManager to do the adding of items to the Dictionary or retrieval or removal (with destruction).
Examples of classes - seriously cut down..
clsManager:
Public WorkingObjects As New Scripting.Dictionary
Public Function AddWorkingObject(key As String, ObjectType As Object) As Boolean
If Me.WorkingObjects.Exists(key) Then
Me.WorkingObjects.Remove key
Me.WorkingObjects.Add key, ObjectType
Else
Me.WorkingObjects.Add key, ObjectType
End If
End Function
Public Function GetWorkingObject(key As String) As Object
If Me.WorkingObjects.Exists(key) Then
Set GetWorkingObject = Me.WorkingObjects(key)
Else
Set GetWorkingObject = Nothing
End If
End Function
Public Function DestroyObject(obj As Object) As Boolean
Dim key As String
If Not obj Is Nothing Then
key = obj.DictionaryKey
If Me.WorkingObjects.Exists(key) Then
Me.WorkingObjects.Remove (key)
Set obj = Nothing
If obj Is Nothing Then
Debug.Print key & " destroyed"
Else
Debug.Print obj.DictionaryKey & " NOT destroyed"
End If
End If
Set obj = Nothing
End If
End Function
clsQuote:
Option Compare Database
Option Explicit
'use a form using an instance of this class to control manipulation of Quote records
'Loading and saving set default values if a null value is detected
Private Const scTABLE As String = "tblQuote"
Private intID As Long 'unique identifier
Private intCustomerID As Long
Private intSiteID As Long
Private rsQuoteTotalValues As DAO.Recordset
Private oCustomer As clsCustomer
Const ObjectType = "Quote-"
Private oEditForm As Form_frmQuote
Property Get EditForm() As Form_frmQuote
Set EditForm = oEditForm
End Property
Property Get ID() As Long
ID = intID
End Property
Property Let ID(QuoteID As Long)
intID = QuoteID
Me.EditForm.ID = QuoteID
End Property
Property Get Customer() As clsCustomer
Set Customer = oCustomer
End Property
Property Let CustomerID(ID As Long)
intCustomerID = ID
oCustomer.Load (ID)
EditForm.SiteID.RowSource = oCustomer.AddressSQL
EditForm.SiteID.Requery
EditForm.ContactID.RowSource = oCustomer.ContactsSQL
EditForm.ContactID.Requery
EditForm.CustomerID = ID
End Property
Property Get DictionaryKey() As String
DictionaryKey = ObjectType & CStr(Me.ID)
End Property
'END PROPERTIES//////////////////////////////////
Public Sub DisplayForm(Visibility As Boolean)
With Me.EditForm
.Visible = False
.subFrmQuoteSectionsSummary.SourceObject = ""
If Visibility = True Then
...some stuff...
.Visible = True
End If
End With
End Sub
Public Function Load(ID As Long) As Boolean
'On Error GoTo HandleError
Dim RS As DAO.Recordset
Dim sQry As String
Load = False
If Nz(ID, 0) <> 0 Then
sQry = "SELECT * FROM " & scTABLE & " WHERE ([ID]=" & ID & ");"
Set RS = Manager.DB().OpenRecordset(sQry, dbOpenForwardOnly)
With RS
If .RecordCount = 0 Then
MsgBox "Cannot find Quote with ID = " & ID, vbCritical
GoTo Done
End If
Me.ID = Nz(!ID, 0)
Me.CustomerID = Nz(!CustomerID, 0)
Manager.AddWorkingObject Me.DictionaryKey, Me
Me.EditForm.SetOwnerObject (Me.DictionaryKey)
.Close
End With
Set RS = Nothing
Load = True
End If
Done:
Exit Function
HandleError:
MsgBox "Error in Customer Load: " & vbCrLf & Err.Description, vbCritical
Resume Done
End Function
Private Sub Class_Initialize()
Debug.Print "Quote class initialized"
Set oCustomer = New clsCustomer
Set oEditForm = New Form_frmQuote
Me.ID = 0
Set oQuoteTidier = New clsClassTidier
Me.DisplayForm (False)
End Sub
Private Sub Class_Terminate()
Set oCustomer = Nothing
Set oEditForm = Nothing
Debug.Print "Quote class terminated"
End Sub
From the EditForm:
Option Compare Database
Option Explicit
'necessary for the object to have a reference to its owner in this manner to prevent circular reference
Private OwnerObject As clsQuote
Public Function SetOwnerObject(OwnerKey As String) As Boolean
SetOwnerObject = False
Set OwnerObject = Manager.GetWorkingObject(OwnerKey)
SetOwnerObject = True
End Function
Private Sub cmdClose_Click()
OwnerObject.EditForm.Visible = False
Manager.DestroyObject OwnerObject
DoCmd.Close acForm, Me.Name
End Sub
Each business object class (like ClsOrder) has an editForm instance which is loaded and hidden until required and a up to 3 DAO Recordsets that it keeps open.
I think all references to the business objects that are interrelated are pointers to the objects in the dictionary.
My problem is error 3035 exceeding system resources. I’ve checked objects are destroyed when not in use but repeatedly opening and closing objects gets me to error 3035.
So the question is- am I just asking Access to do stuff it can’t or would better programming fix it?
I see ZERO reasons to write all that code. Why not let a form handle all of this? Remember, each form is in fact a "class" instance. You can even launch multiple copies of a single form, each with their own code, own data and each instance of the SAME form can operate 100% independent of other working copies of that same form.
If you attempting to look at this problem and wanting to have a class object for a form, then just use the form object - that's what it does for you!
I see zero benefits from writing all that code. While .net has the dataset manager and system (and now the very similar entity framework, this is MUCH done since .net does not have data bound forms.
In Access, each form is in fact a class object. And that includes any public sub or function for that form (so functions become methods of that form, and public vars become properties of that form). In addition to the bound form having a truckload events, these events work as actions against any data editing. So, unlike most systems, you have "on change" event, before update event, after update event. So, by simply adoptiing a bound form, then you get:
A class object is automatic created for you.
You can have multiple instances of that class, and hence multiple instances of that same form open at the same time.
You get all of those data events that can be used for verifiction of data input (or have the user not save the record until such time your critera is met.
You have full use of all data columns, even if controls are NOT placed on the form bound to those columns. So, you even get intel-sense for all of the data columns - that is you map.
I am not aware that there is some big huge circular reference problem here. This is like stubbing your toe, but then going to the doctor for some huge open heart by-pass operation. So to go on some huge massive coding spree, and chew up huge amounts of developer dollars for some "rare" issue of some kind of rare and un-seen circular reference issue is essentially a huge wild goose chase that will only have you chewing up huge amounts of developer code and time when NONE is required at all.
I mean, if you have say 3 instances of the SAME form open? Then how does the code know and refernce what insance of that form? Well, the EXACT same approac used in typical OO programming can and should be used here. That approach means you don't HARD CODE the forms! name or referances in code EVER. You never want to do this.
So, if you are in a sub form, and need to referacne say data or controls in the parent form?
You could do this:
strLastName = forms!frmCustomer!LastName
In above, we have hard coded the forms name. You don't want to do that.
In that subform, the correct way to write this code is:
strLastName = me.Parent.form!LastName
Now, note how the above referances the parent form. So, that code will work EVEN if we have 3 copies of the frmCustomer active at the same time. You can full refernce ANYTHING in a form by its object "instance". So, in JavaScrip, or c#, you often see "this.SomProperty" as a refeance to that object.
In access, you can do the same thing, and use "me". Or me.Parent.From to reference the parent form. So, as a general approach here, you should NEVER have to hard code forms reference. If you take this approach, then all issues of circular referencing will not only be eliminated, but then you are using a classic and traditional approach to object programming, and object referencing. While Access is not full OO, it certainly follows a lot of OO design concepts, and how forms work in Access are most certainly instances of a object.
Attempting to write truckloads of code when the forms object model already exists as a "single" class object instance of that form makes no sense, and is not required, and the road you going down will likely hamper and reduce your abilities to deal with the fantastic instance of that form you already have.
As noted, the form already has the dictionaly and columns attached, and Access EVEN generates the members for your automatic. The result is you can reference any column of the table that the form is bound to with
me.LastName
me!LastName
While the above two formats are allowed, the first (me + dot + column name) is in fact a member of the forms class. You will find that if you use code to set the forms data source, then often these members are NOT generated for you, and thus you have to use the ! (bang) to reference columns from the table for that form.
So, I don't grasp while you attempting all that extra code when the form has all of the abilities you are asking for in a class object.
So, i want to do what I feel should be such a simple task... pass in a parameter to a constructor using Autofac!
However, I have managed to get a work around working, but just dont think this is correct, I feel i am chaning too much of the recommended code from the Autofac guides
I am more than happy for answers in C# or VB.net it doesnt matter, the location of code is all the same
So, here is my setup (im not fussed about neatness, just trying to get this to work for now)
In my global.asax I have:
'***Note, the autofac guide had this a a private shared, see below for why i changed it***
' Provider that holds the application container.
Public Shared _containerProvider As IContainerProvider
' Instance property that will be used by Autofac HttpModules
' to resolve And inject dependencies.
Public ReadOnly Property ContainerProvider As IContainerProvider Implements IContainerProviderAccessor.ContainerProvider
Get
Return _containerProvider
End Get
End Property
then within my global.asax within application_start I have:
***again, note, originally I was using IMyClass when registering type... not sure this or that is correct***
Dim builder As New ContainerBuilder()
builder.RegisterType(Of MyClass)().As(Of MyClass)().InstancePerLifetimeScope()
'... continue registering dependencies...
' Once you're done registering things, set the container
' provider up with your registrations.
_containerProvider = New ContainerProvider(builder.Build())
As you can see, origianly the _containerProvider was just public, but I have had to make it "Shared" for this to work, this feels wrong right away!
so, now, in my webForm1.aspx.vb I have this:
Public Property MyClass2 As IMyClass
Private _myClass As IMyClass
Now, because I have adjusted the global to "registerType" to use the actual object, not the interface (which, again seems wrong having to change that too), means now my webform public property is not being set (but, because of my work around, i dont need that anyway)
Also, note the private _myClass... this is for my workaround
so, now in my Webform init method, i have the following:
WebForm1.aspx.vb*
_myClass = [Global]._containerProvider.RequestLifetime.Resolve(Of MyClass)(New TypedParameter(GetType(HttpRequest), Request))
which now instantiates my _myClass with the parameter correctly injected in... this is great, whoopadeedoo
...but... I dont think this is correct.
Now, when I didnt need to pass in a parameter to the construtor, it all worked nice, didnt need to change any of the code from the autofac guide, it just worked, set the public property on my webform.aspx page fine, was really nice.
But, as soon as I start to work with a paramter being passed into the construtor, it seems everything needs to be tweaked so it will work? is this correct?
I have even tried the deligate guide from autofac, but that also doesnt work for me at all by doing this within my webForm.aspx page:
Dim container As ILifetimeScope = [Global]._containerProvider.RequestLifetime
Dim myClassFactory As MyClass = container.Resolve(Of MyClass.Factory)
Dim myClassholding As MyClass = myClassFactory.Invoke("ABC")
even tried without the "Invoke", but "cannot be indexed because it has no default property"
Just incase it helps, here is "myClass"
Private _myID as integer
Public Delegate Sub Factory(myID As integer)
Sub New()
End Sub
Sub New(myID As integer)
_myID = myID
End Sub
Public Sub DoSomething() Implements IDfCookieManager.DoSomething
'do something with myID
End Sub
I know I can pass the id in as a parameter to DoSomething, but i want to understand how to pass this into the constructor
so, my questions:
If this is not how to do this (which I am hoping its not correct), how would I do this without needing to change all the global setup??
Is it best to use a deligate factory or just resolve?
do I really need to change the global container to be shared/static, so that i can access the container from within my code?
So, there are two ways, but firstly, shouldnt need to mess around with how Autofac suggests setting up the ContainerProvider in global.asax... i can keep it as non shared (not static), and to access this value I do the following:
Dim cpa As IContainerProviderAccessor = (CType(HttpContext.Current.ApplicationInstance, IContainerProviderAccessor))
Dim scope As ILifetimeScope = cpa.ContainerProvider.RequestLifetime
Also, in our webform.aspx page, Public Property MyClass As IMyClass should not be added when we need to pass in parameters to the constructor when resolving (otherwise it will be resolved before we try to manually resolve it!
1: Passing in using TypedParameter
Here is my adjusted code to pass in the parameters using resolve (including the lines above):
Dim cpa As IContainerProviderAccessor = (CType(HttpContext.Current.ApplicationInstance, IContainerProviderAccessor))
Dim scope As ILifetimeScope = cpa.ContainerProvider.RequestLifetime
Dim myClass As MyClass = scope.Resolve(Of IMyClass)(New TypedParameter(GetType(Integer), 123))
Also, having the public property at the top of my WebForm1.aspx needed to be removed, because that will auto resolve, meaning, if i try to "resolve" the object manually, it has already been automatically resolved by autofac (which is why i thought my code wasnt working initially), and has already instantiated the object with the empty constructor!
2: Using a Deligate Factory
the line Public Delegate Sub Factory(myID As integer) isnt correct, it should use a function for Autofac to automaticly set this up! so should be: Public Delegate Function Factory(myID As integer) as MyClass
In Global.asax, I just need to add this builder.RegisterType(Of MyClass)().InstancePerLifetimeScope(), because we require a parameter and using a factory, we cant append the .As(Of IMyClass)
Finally, our webform1.aspx.vb just needs this:
Dim cpa As IContainerProviderAccessor = (CType(HttpContext.Current.ApplicationInstance, IContainerProviderAccessor))
Dim scope As ILifetimeScope = cpa.ContainerProvider.RequestLifetime
Dim myClassFactory As MyClass.Factory = scope.Resolve(Of MyClass.Factory)
_myClass = myClassFactory.Invoke(123)
however, I tweaked that slightly to this:
Dim cpa As IContainerProviderAccessor = (CType(HttpContext.Current.ApplicationInstance, IContainerProviderAccessor))
Dim scope As ILifetimeScope = cpa.ContainerProvider.RequestLifetime
Dim myClass As MyClass = scope.Resolve(Of MyClass.Factory).Invoke(123)
I'm using ASP.NET Web API to return a custom class object. The class has several properties, one of which takes an optional parameter. All the properties except the one with the optional parameter are available in the resulting JSON response. If I remove the optional parameter the other property is then available as well. Any way to return the other property with the optional parameter in place? Thanks!
Here is the specific property I'm having trouble with:
Public Class customer
...
Public ReadOnly Property photoSrc(Optional shape As String = Nothing) As String
Get
Dim srcString = "/Images/User.png"
If shape = "square" Then
srcString = "/Images/UserSquare.png"
End If
Return srcString
End Get
End Property
...
End Class
And here is the api controller function I'm using to return json:
Public Function GetCustomer(id As Integer) As Object
Dim customer As customer = New customer(id)
Return customer
End Function
A property with a parameter is called an indexed property, or indexer. By design, Json.Net (which is used by Web API for JSON serialization) does not serialize indexed properties, even if the index parameter is optional. (You can see this for yourself in the source code for the GetSerializableMembers method of the DefaultContractResolver class.)
The simplest workaround is to add a separate non-indexed property to your class which calls the indexer with the parameter value you want it to have when serialized. You can make the property private if you want; if you do, you just need to mark it with a <JsonProperty> attribute to allow the serializer to "see" it. You can also use this attribute to give the alternate property the same name in the JSON as the indexed property it is replacing.
Public Class Customer
...
<JsonProperty("photoSrc")>
Private ReadOnly Property defaultPhotoSrc As String
Get
Return photoSrc()
End Get
End Property
Public ReadOnly Property photoSrc(Optional shape As String = Nothing) As String
Get
Dim srcString = "/Images/User.png"
If shape = "square" Then
srcString = "/Images/UserSquare.png"
End If
Return srcString
End Get
End Property
...
End Class
Fiddle: https://dotnetfiddle.net/ffNs9D
We are using Spring MVC 4.1.2 and Spring Data JPA 1.9.0. Everything works fine but when we have custom query with only selected field for a given entity then our json response does not include property name in the response, instead it just included property value.
If I correctly guess, your custom query looks like:
SELECT e.myProperty FROM Entity e [WHERE ...]
The effect of this is that you get a List<Object[]> containing only the array of property values instead of an object that has a field with the name myProperty and its value is the value in the database.
The solution is to create a custom data-transfer object, which has this one field and assign the value in the constructor
public class MyPropertyDTO { // find a better name, though :)
private int myProperty;
public MyPropertyDTO(int myProperty) {
this.myProperty = myProperty;
}
public int getMyProperty() {
return myProperty;
}
}
Then rewrite your query as:
SELECT NEW com.mycompany.MyPropertyDTO(e.myProperty) FROM Entity e [WHERE ...]
In theory you could even use your original Entity class, add a json view on myProperty and create the matching constructor instead of creating a brand new class.
I need an ASP.Net control on your property you can specify an array type string. That is, in my ASP.Net control would have something like:
DefaultValue("")> Category("Misc"), <Bindable(True),
Public Overridable Property MyProperty () As String ()
Get
Return mMyProperty
End Get
Set (ByVal value As String ())
mMyProperty = value
End Set
End Property
And from the ASP.Net page I need to pass the values, type:
<WC:MyControl MyProperty="1,2,4" runat="server" />
The message error is:
Cannot create an object of type 'System.String[]' from its string representation '1,2,4' for the 'MyProperty' property.
You need to implement a TypeConvertor for this.
These resources could help you with it:
How to: Implement a Type Converter
Passing int list as a parameter to a web user control
Passing int array as parameter in web user control