Sql Server - Obtain A List Of Collections Which Contain Objects Which Implement An Interface In C#
Aug 28, 2010
I am new to .Net Programming and would like to know if Reflection is suitable for traversing an Object to discover Collections within an instance of a class. I am working with the Microsoft.SqlServer.Management.Smo Namespace.
The plan is to connect to a database, determine what collections exists, then for each of those collections, if the Collection exposes objects which implement the IScriptable Interface, generate a script for the object.How do i do the following (This is pseudo-code as I am seeking assistance with using reflection or some other method to do the following)
[Code]...
I would like to enumerate all objects in db with one function if possible
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Jan 19, 2011
All my data objects implement an interface IFillable
Public Interface IFillable
Sub Fill(ByVal Datareader As Data.IDataReader)
End Interface
In the objects themselves you will typically see something like
Public Class Supplier
Implements IFillable
[Code]...
Now here is the tricky bit. Given that all my property names WILL ALWAYS match my database column names what I want to do is using reflection generate the fill method at compile time and infer the types and column names for the datareader.I am assuming I will need to structure this functionality as some sort of a tool/vs plugin? What I am looking for is guidance on the best way to go about this.
PS: BTW: Obviously I could easily do this using reflection at runtime but I dont want to take the performance hit for it (Although theoretically if I could cache the values somehow (static class?) it might not be too bad).
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Mar 20, 2009
I need another (dozen) pair of eyes on this. The following code:
Interface iRuleEntity
Function GetRuleViolations() As List(Of RuleViolation)
End Interface
Partial Public Class Feedback
[code]....
is giving me this error:'Feedback' must implement 'Function GetRuleViolations() As System.Collections.Generic.List(Of RuleViolation)' for interface 'iRuleEntity'.
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Mar 9, 2010
I have started using BindingList(Of T) for my generic collections whenever I need the objects to interface with the GUI instead of List(Of T). This has worked well for me so far but a few of my collections are stored in Dictionary(Of TKey, TValue) and there doesn't appear to be a corresponding BindingDictionary(Of T).
Has anyone else come across the necessity to use this, and how did they achieve it? Should I implement this myself? (How?) or is there a better solution already available?
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May 26, 2011
I have an object (MyObj) that itself will hold a List of other objects of various types and I want to count them as they are added to MyObj.That's the simple explanation, anyways...I have an Interface (MyInterface) that all sub-objects agree to. MyObj has a List(Of MyInterface) property that all the sub-objects are added to. MyInterface will expose a property that lets me figure out what subtype each object is (the sub-objects do not inherit from MyObj at all).
But I want to count these sub-objects as they are added to the list, and I'm trying to find a good way to do it. I don't need to worry about decrementing the count, as I am going to mimic the behavior of String and just create a new instance of MyObj if it ever changes, so all my counts will start from 0. This'll hit the garbage collector a bit, but I think this will allow for simpler (and safer) code. The only sane way I can think of to count objects is a very large structure in MyObj that uses bytes to hold the count (I will never have more than 255 of any given sub-object in the list in MyObj). But, even using bytes, this structure will be about 100-200 bytes big in memory (I have that many sub-objects), and I anticipate having a fair amount of MyObj copies running around, too.
I'll also need a large Select Case to know which count property to increment when a new sub-object is added. This seems to be a bit ugly, though I've used this approach several times already.What I am wondering is, instead of counting each object as it is added to the list, is there some way to query the list and count only the objects of a specific type? I wouldn't need to store this anywhere, since it would be dynamic, like querying a database and asking for a count of a specific column or type of record.I suspect Linq can do this, but Linq is also quite slow. Are there other approaches? Perhaps a predicate of some kind?VB (I am not a C# guy):
From i in MyObj.MyList Group i by i.GetType into g Let c as Int32 = g.Count() And that's it so far. I am still googling, but I am getting way too many C# and SQL references.
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Sep 21, 2011
I'm having a problem with this code in the highlighted line(*); getting the error in the heading.
Dim htmlarraylist As New List(Of iTextSharp.text.IElement)
htmlarraylist = *HTMLWorker.ParseToList(New StreamReader(tempFile), New StyleSheet())*
[Code].....
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Feb 5, 2011
[code]...
What's really the point in using the former?It's hard to use linq if I used the former. I have to convert that to an array first which is difficult because there is no (asarray) function.I think I would change all of my code that's using System.
Collections.Specialized.StringCollection to System.Collections.Generic.List(Of String)
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May 19, 2009
Pages have Roles. Users have Roles. A user may only view a page if he and it share one or more roles.
This works:
Dim Allow As Boolean = False
CurrentPage.Roles.Load()
For Each r As Role In CurrentPage.Roles
r.Users.Load()
[Code]...
How can I make it compare only the Role Id values to determine equality?
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Nov 24, 2011
I'm implementing a customized Graph algorithm in vb.net, and I'm having the following problem:
Supose the code:
dim col as new collection
dim myC as new system.collections.genericList(of myClass)
dim obj1 as new myClass
dim obj2 as new myClass
[code].....
'In the next statement, the myC2 inside col collection will be decreased to contain 'only obj1, like myC. I supose this is for myC and myC2 contains only a pointer to 'objects obj1 and obj2 as well col contains pointers to myC and myC2 myC.remove(obj2)'The problem is that I have to only copy myC to myC2, like a ByVal argument in a function,'instead a ByRef argument, in order to mantain a copy of objects in myC2 while these 'objects should be removed from myC. How should I do it?
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Jan 27, 2010
lets say I have:
arecord.name = "A"
arecord.value = 15 ' a number of type "long"
'
I then
call records.add(arecord,arecord.name)
' so far, so good but lets look at the next record
arecord.name = "B"
arecord.value = "this is text" as opposed to a number of type "long"
'can I then
call records.add(arecord,arecord.name)
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Nov 1, 2009
I am developing a software that would scan the image in a picturebox and obtain the rgb values of each pixel in the image and convert each rgb values to HSL values. I am using vb 2008 express edition. I am still a student. All I have done is to obtain the image in a file and paste it in the picturebox. Below is my code. I dont really know how to start with the process of obtaining the rgb values of each pixel and converting them to HSL values and averaging the HSL value.[code..]
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May 3, 2012
i have issue returning a list in a web method. here is the code
<WebMethod()> _
Public Function getTags(para_parents As String) As List(Of getTypeDetailsByParentName_Result)()
Dim context As New PPEntities
[code]....
the error is
Value of type 'System.Collections.Generic.List(Of SaftyonRoad.getTypeDetailsByParentName_Result)' cannot be converted to '1-dimensional array of System.Collections.Generic.List(Of SaftyonRoad.getTypeDetailsByParentName_Result)'
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Aug 7, 2009
I am trying to implement an interface defined in IDL, in a vb.net class here is the idl
interface IEmissaryRoot : IDispatch {
id(0x68030000), propget]
out, retval] IActivityCol** );
[code]....
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Jul 25, 2010
I'm trying to assign a datasource to a ComboBox control during runtime. When I do so, I get the attached message. [Code] I want to learn how to use an Interface. The error message is suggesting using an IList. How would I do this.
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Mar 12, 2009
I have converted c# .cs to vb:= I have 6 errors on:
Red "List" says Too few type arguments to system.Collections.Generic.List(Of T)'
Orange "Calendar" says Value of type 'System.Windows.Forms.Control.ControlCollection' cannot be converted to 'Form1.Kobush.Windows.Forms.Appointment'.
[code]....
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Mar 21, 2011
My problem is probably something simple..I am trying to load a list of a perticularcustomer.I will have to load the list of all the purchases they have make (amount of tickets purchased (rseat). It runs fine, but when I change the file name from fri to saturday and keep the call name the same it still searches to the name that is in the call name textbox. I dont want it to do that. I want it to say the there are no reservation for that name if I change the file.here is part of my code.
Private Sub btnSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSearch.Click
'resets file reader and put to the top of txtfilename
[code].....
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Nov 24, 2006
I have a situation where I am defining an interface and then using that directly eg:Dim x as IWhatever = new implementationOfIWhatever()Which is fine, butmplementationOfIWhatever also implements IDispoable so I want to be able to do x.Dispose or ideally Using x but get the error that that this is not declared or must implement IDispoable as IWhatever of course doesn't define Dispose or implement IDispoable
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Nov 18, 2009
I am trying to implement an interface on an ASP.NET 3.5 web page that will let the user specify up to three conditions for insertion into a Linq to SQL query. It looks something like this:
[Code].....
how to assemble my query from the values in the various DDLs and TestBoxes.
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Jul 16, 2009
I have an interface program written in VB .Net (VS2008xxx.dll). Is it possible to implement the Interface in a VB6 program (VB6xxx.exe)?
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Dec 23, 2009
Say I want to know more about a class mshtml.htmlinputelement for example.Say I want to know. What is his parent classes? What interface the class implement? How do I do so through object browser?
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Feb 15, 2012
I'm trying to learn how to work with Collections list. In the past, if I wanted to create a list I would use an array and then save it to a text file after I was done manipulating the data via CSV.how to save things of different types to a list such as:
Name, Birthdate(as date), Salary
I know how to do this in an array but all the synapses aren't firing with the "new to me" collections list as collections lists are hard typed....
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Sep 21, 2009
I have a class in VB with some constants that represent the string name of my security roles. I need to be able to call a function to return to me a string array(or collection, or whatever) of the values of each of these constants. I will be using it to make sure that my databases Roles table has the same roles as coded into the application.
[Code]...
I'm looking to run a function, i.e. ClassConstantsToStringArray(gettype(Roles)) that will return to me "Administrator","Basic User","Power User" I'm know reflection is the way to go, I just don't know enough about using it yet to get what I want. I found a function on the net that would return to me the constant names in a FieldInfo array but still don't have enough smarts to make that work for me.
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Jun 7, 2011
is it possible to implement strategy pattern with different parameters in VB.net? For example I have the following code:
Public Interface InterfaceDataManipulation
Sub updateMyData()
End Interface
How to implemente updateMyData in the class that implements above interface class with different parameter,for example in class x :
Public Class X
Implements InterfaceDataManipulation
Public Sub updateMyData(ByVal x as String)[code]......
But the IDE raises an error "class x must implement updateMyData on interface InterfaceDataManipulation"
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Jul 13, 2010
I defined the following interface:
Interface INewFileDetector
...
roperty PollIntervalMsec As Integer
[code].....
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Sep 21, 2011
I need to implement an event interface defined in a COM app so I can get events. I want to use System.Runtime.InteropServices.ComTypes.IConnectionPointContainer. In Adam Nathan's ".NET and COM", Adam shows some C# code that connects to an IE event set. There he does this:
[Code]...
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Mar 3, 2010
I am a C# programmer but I have to work with some VB.Net code and I came across a situation where I have two methods on an interface with the same name but different method parameters. When I attempt to implement this interface in a class, VB.Net requires explicitly declaring "Implements MethodName" after the method signature. Since both method names are identical, this is confusing the compiler. Is there a way to get around this sort of problem? I suspect this must be a common occurrence. Any thoughts?
N.B. This was more a case of the programmer not verifying that the interface in question had not changed from underneath him.
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Jul 30, 2009
Do i have to implement the serial port in the interface again if i have put it in the behind code? Do have any links that can make me understand.
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Jul 19, 2010
i may be misunderstanding this but on MSDN i believe it says that it is good practice to implement the Dispose destructor in every class you write. should i (do you) really implement the IDisposable interface with every class i write? also, is the proper syntax for implementing an interface to put the "Implements" keyword on the line after the "class" declaration? i put it on the same line as "class" and I got an error.when coding the method implemented by the interface, is it mandatory to follow this syntax, as an example: Public Sub Dispose() Implements System. IDisposable. Dispose.
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Oct 20, 2010
i want to exclude some form fields when processing a postback. I done the following but having some issues:
Dim rtnValues As New StringBuilder
Dim arrJoinValues As String = String.Join("|", _setFormValues.ToArray)
Dim arrSplitValues() = Split(arrJoinValues, "|")
[Code].....
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Jan 27, 2010
imagine i want to add an extension method to System.Collections.Generic.List(Of T)
let's say i want to give it .GetUBound which returns Count-1
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