I use class Page that handles some information. But I don't know what to choose for the name of the method: getInnerPage($uname) or getSubPage($uname)
The base page may look like this: http://abc.net/base
And the inner or sub: http://abc.net/base/sub
We often use sub, which represents a hierarchical view, whilst inner would be more appropriated for containers' content.
but I don't know if there really are conventions for this
Related
I want to execute the method remove_column on an instance of cl_salv_column_table but because of its visibility level, I am not able to do so.
Plan:
I already tried inheriting from cl_salv_columns_list and then perform the call inside the remove-method:
CLASS lcl_columns_list DEFINITION INHERITING FROM CL_SALV_COLUMNS_LIST.
PUBLIC SECTION.
METHODS:
remove IMPORTING iw_colname TYPE string.
ENDCLASS.
But apparently my casting knowledge got rusty as I'm not able to figure out an appropriate solution.
This is my current hierarchy - the red arrows show the way I would have to take:
My approach looks like this:
DATA lo_column_list TYPE REF TO lcl_columns_list.
lo_column_list ?= CAST cl_salv_columns_list( lo_columns ).
But it fails with:
CX_SY_MOVE_CAST_ERROR
Source type: \CLASS=CL_SALV_COLUMNS_TABLE
Target type: "\PROGRAM=XXX\CLASS=LCL_COLUMNS_LIST"
Background:
My task is to select all columns of 3 tables (which would be done like SELECT t1~*, t2~*, t3~* ...) as long as their names don't conflict (e.g. field MANDT should only be displayed once). This would require defining a very big structure and kick the size of the selection list to a maximum.
To avoid this, I wanted to make use of the type generated by my inline-declaration. Hiding the individual columns via set_visible( abap_false ) would still display them in the layout manager - which looks really ugly.
Is there any other way to accomplish my target?
Use set_technical( abap_true ) to hide the columns entirely. As for your approach - sorry, inheritance does not work that way - in no statically typed object oriented language that I know. You can't 'recast' an instantiated object to a different class. You would need to modify the framework extensively to support that.
I have a block of related sub routines I would like to "group" together within class to make navigating a littel easier. When I say group, I mean achieve the same functionality of being able collapse and expand a block of code as would with single procedure or class. Two alternative ways I can think to accomplish this is either use a partial class for those procedures or use namespace. I just wanted to see if VS for VB.Net had another way to be able group and collapse blocks of procedures. Thanks.
In VS 2005 at least you can use:
#Region "NameOfRegion"
' Methods go here
#End Region
That will allow you to collapse the region just like any other block of code within VS.
Yes, you can use the region directive:
#region Some Idenfifier
... Code ...
#endregion
You can then collapse or expand the entire region to show the code contained.
You can use a region
#Region "MathFunctions"
' Insert code for the Math functions here.
#End Region
Region information
I have a class called PriceStep. I keep a list of PriceStep objects in a class called PriceStepSearchSpace. Now I am required to have different PriceStepSearchSpace objects for different products and I need to keep them in some sort of a dictionary. I called this new class PriceStepSearchSpaceRepository.
Can you think of a simpler/shorter name?
You could call it Repository and put it in a namespace called PriceSteps.Searchspaces.
I might call it PriceStepSearchSpaces if it was unlikely that I would have any other type of collection of those objects. Otherwise, I like Timwi's idea of putting related classes into a namespace to prevent duplication of prefixes.
I would go with SearchSpace for your first and SearchSpaceDictionary for the second.
There's no need to preface a parent class with it's child class name!
However, you may want to re-think your object model, it's hard to give advice about that based on the info you provided.
PriceStep. PriceSteps. PriceStepsByProduct.
Is setX() method name appropriate for only for setting class property X?
For instance, I have a class where the output is a string of an html table. Before you can you can call getTable, you have to call setTable(), which just looks at a other properties and decides how to construct the table. It doesn't actually directly set any class property -- only causes the property to be set. When it's called, the class will construct strHtmlTable, but you can't specify it.
So, calling it setTable breaks the convention of get and set being interfaces for class properties.
Is there another naming convention for this kind of method?
Edit: in this particular class, there are at least two ( and in total 8 optional ) other methods that must be called before the class knows everything it needs to to construct the table. I chose to have the data set as separate methods rather than clutter up the __construct() with 8 optional parameters which I'll never remember the order of.
I would recommend something like generateTable() instead of setTable(). This provides a situation where the name of the method clearly denotes what it does.
I would probably still use a setTable() method to actually set the property, though. Ideally, you could open the possibility of setting a previously defined table for further flexibility.
Yes, setX() is primarily used for setting a field X, though setX() may have some additional code that needs to run in addition to a direct assignment to a field. Using it for something else may be misleading to other developers.
I would definitely recommend against having a public setTable() and would say that setTable() could be omitted or just an unused private method depending upon your requirements.
It sounds like the activity to generate the table is more of a view of other properties on the object, so you might consider moving that to a private method on the object like generateHtmlTable(). This could be done during construction (and upon updates to the object) so that any subsequent calls to getTable() will return the the appropriate HTML.
I am attempting to create a generic function that the students in my introductory VB .NET course can use to search a single dimension array of a structure.
My structure and array look like this:
Private Structure Survey
Dim idInteger As Integer
Dim membersInteger As Integer
Dim incomeInteger As Integer
Dim stateString As String
Dim belowPovertyLevelBoolean As Boolean
End Structure
Private incomeSurvey(199) As Survey
My generic function header looks like:
Private Function FindSurveyItem(Of xType As Structure)
(ByVal surveyIDInInt As Integer, ByVal surveyArrayIn() As xType) As Integer
??????
End Function
My call to the function looks like:
If FindSurveyItem(Of Survey)(CInt(idTextBox.Text), incomeSurvey) <> -1 Then
My question is: Is there a way to reference the individual structure fields in the array from inside the function? I was trying to make it generic so that the student could simply pass their array into the function - their structure may be named differently than mine and the field names may be different.
I suspect there are other ways to deal with this situation, but I was trying to keep it to just a simple single-dimension array of a structure. I don't think it is possible to do what I want, but I wondered what others thought.
Is there a way to reference the individual structure fields in the array from inside the function?
Generic instead of an array you need a collection type. Add LINQ Code:
Dim Surveys = From svys In xType
Where svys.idInteger = surveyIDInInt
Select svys
For Each rSurveys In svys
'''' Your Code
Next
This is rough answer fill in the details (I know imagine LINQ without SQL DB!!)
If you have a genric type parameter T you are only able to access members of instances of T that are known to exist at compile time. As every type derives from Object you have only the members of Object availiable - ToString(), GetType(), GetHashCode(), and Equals().
If you want to access other members you have to constrain what T is allowed to be. In your situation a interface would be the way to go. See MSDN for details.
You could also try to use reflection or check the actual type at runtime an perform a cast. The first is hard to impossible to do if you do not know much about the types you will get. And the later requires you to know possible types at compiletime and will not work in your situation, too.
Another way might be to pass a delegate to the search method that performs the actual comparison.
What you're looking for are predicates, if using ,net 3.5
dim arr() as structure
Array.Find(arr, function(item)(item.MyMember = MemberToMatch))
More combersome in earlier versions, see here for more info
The point being, that your function would look very like an implementation of Array.Find (if you didn't want to use the function provided), and the students would need to write their own predicate function.
No, there isn't. You can't know the type at compile time, therefore you cannot access members of that type. You would need change from a structure to a class that must implement IComparable so that you can use CompareTo between the item you pass in and the array you are passing in.
Though it's not entirely clear what you are trying to do within your method so I'm guessing by the name of the method.
You can use reflection to get those fields, but in this case that wouldn't have much meaning. How would you know that the passed type has the field you're looking for? There are other problems with that code as well.
Instead, to do this I would normally create an interface for something like this that had a public ID property, and constrain my input to the function to implement that interface, or as others mentioned use a built-in feature in the clr.
But that may be ahead of where your students are. If you just want an example of a generic function, my suggestion is to show them a type-safe implementation of the old vb imediate if function:
Public Function IIf(Of T)(ByVal Expression As Boolean, ByVal TruePart As T, ByVal FalsePart As T) AS T
If Expression Then Return TruePart Else Return FalsePart
End Function
Note that this is obsolete, too, as in VS2008 and beyond you can use the new If operator instead, which will work better with type inference and won't try to evaluate the expression that isn't returned.