Checking An Object's Parent Types By String?
Apr 15, 2011
I'm trying to figure out how find an object's type when it is a subclass of another object and I only know the string value of the object's type's name.I created the follwing classes:
HTML
Public Class word
End Class
Public Class noun[code]....
The problem is, using 'GetType' to check pn against a string value, I can only see that pn is a properNoun, not that its parent classes are noun and word.Is there a way to check pn against the string value "noun" or "word" and get back a positive result, indicating that pn is indeed a noun and a word as well as a properNoun?
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Apr 15, 2011
how find an object's type when it is a subclass of another object and I only know the string value of the object's type's name.
I created the follwing classes:
Public Class word
End Class
Public Class noun
[Code]...
Using 'TypeOf', I correctly see that pn is a properNoun, a noun and a word. The problem is, using 'GetType' to check pn against a string value, I can only see that pn is a properNoun, not that its parent classes are noun and word.
Is there a way to check pn against the string value "noun" or "word" and get back a positive result, indicating that pn is indeed a noun and a word as well as a properNoun?
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Nov 1, 2009
I have a class with a Property called 'Value' which is of type Object.Value can be of any type, a structure, a class, an array, IList etc.My problem is with the setter and determining whether the value has changed or not.This is simple enough for value types, but reference types and lists present a problem.For a class, would you assume that the Equals method has been implemented correctly, or just assume that the value has changed every time the setter is called?If I did assume it's changed, then perhaps I should assume it for value types as well, so that the behaviour is consistent.
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Jan 12, 2011
In the Session_Start of the Global.asax i have
Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
Session("login") = False
[code]....
Why i am getting error the error Object reference not set to an instance of an object. at line
If Current.Session("login") Is Nothing Then
while checking for the login state as follows?
If GetLogin = False Then
'Do something
End if
I mean i have already created the instance on the Session_Start... Haven't i?
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Jul 6, 2011
I was wondering how I would go about placing a check in the checkboxes for each child node of a parent node in a TreeView control, if I was to check the parent node.
For example:
Parent 1Child 1
Child 2
Child 3
If I was to check "Parent 1" how would I be able to make that event place a checkbox beside all of the child nodes of "Parent 1"? (Child1, 2, and 3.)
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Dec 1, 2011
I am working on a application that has quite a few functions involved and have been thinking of the following: If I have a function that has a few paramaters, is it more efficient to pass the objects to the function(Example 1) or reference the objects in the parent(Example 2)? Does it matter if the objects are large or not?
Example:
Class mainform
Public myGenericList As New List(Of String)
Public myDatarowArray() As DataRow
[Code].....
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Aug 19, 2011
In C# we can do something like this:
Honda a = new Car(); and that works but the same one doesn't work in Visual Basic.NET (I am fairly new to Visual Basic)
Dim a as Honda = new Car and it says Unable to cast object of type 'SampleApp.Car' to type 'SampleApp.Honda'.
Here is my sample code:
Module Module1
Sub Main()
Dim a As B = New A
[Code]....
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Mar 29, 2010
I am having some trouble creating an object array of different object types. Here is what I have so far:
Public Sub New()
Dim b1 As New Book("Book Title 1", "Gold Book Publisher", 1.0, "Bob Jones", "192DJDJD212", "01/02/10")
Dim b2 As New Book("Book Title 2", "Gold Book Publisher", 1.0, "Bob Jones", "192DJDJD212", "01/02/10")
Dim b3 As New Book("Book Title 3", "Gold Book Publisher", 1.0, "Bob Jones", "192DJDJD212", "01/02/10")
[code]....
If I define the array As Book (Public publicationArray(6) As Book) or Magazine (Public publicationArray(6) As Magazine) I am able to access the properties of that class but not both. I think I need to define a type for each array instance but not sure how to do this.
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Apr 27, 2010
VB 2008 .NET 3.5 Suppose we have two classes, Order and OrderItem, that represent some type of online ordering system. OrderItem represents a single line item in an Order. One Order can contain multiple OrderItems, in the form of a List(of OrderItem).
Public Class Order
Public Property MyOrderItems() as List(of OrderItem)
End Property
End Class
It makes sense that an OrderItem should not exist without an Order. In other words, an OrderItem class should not be able to be instantiated on its own, it should be dependent on an Order class to contain it and instantiate it. However, the OrderItem should be public in scope so that it's properties are accessible to other objects. So, the requirements for OrderItem are:
[Code]...
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Sep 27, 2010
I understand that different data types have different uses, String for text, Integer for numerical ect. However, if the Object type can be used for ALL types and supportive of everthign then why should i worry about using correct data types such as string and integer if i can just use "Object" for them all and it will work.I could do
Dim Test as Object = "John"
or i could do
Dim Test as String = "John"
They both do the same thing; there must be something very important im missing here but can only think of one thing that it could be; Memory Management.I think that by using a type such as object may take up more memory than using string?
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Jul 29, 2010
I am building an ASP.NET application that needs dynamic tables. That's another issue that I've already posted about (and gotten a pretty good response!). Now, I'm running into another issue - I want to add new rows to my table, but given that I will have 10-12 tables on one page, each containing different objects in their rows (text boxes, check boxes, etc.) I need a way of simply generically adding a new row that has the same objects as the first row in the table. Here's my code:
Private Sub AddTableRow(ByRef originalTable As System.Web.UI.WebControls.Table)
Dim originalRow As System.Web.UI.WebControls.TableRow = originalTable.Rows(1)
Dim insertingRow As New System.Web.UI.WebControls.TableRow[code]......
Stepping through with a debugger, I see that this strategy is working - but the additional table row still doesn't appear...and still does when I do this statically.
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Aug 31, 2011
I'm all new to this treeview business. I have a fixed treeview, very simple and basic. Only two levels, parent and child nodes. I just need two things out of this treeview.
1) If parent is checked, check all child nodes.
2) If just one child node is unchecked, uncheck parent node.
That's it! I've been looking for this for 30 mins and I cant find it. Maybe because my vb.net is old, it doesnt seem to be the same as others =/ I'm using vb.net 2003.
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Sep 29, 2009
In my application i have set a reference to an activeX component that has been written in vb6(that's not important) What i have done is Here (woo my first hyperlink i hope it works lol) But this is neither here nor there, what i would like to do is put a check to see if the object that has been assigned the activeX component has been assigned it. What i can think of is:If myObject Is Not Nothing Then'set some other stuff End If
The only trouble is, obviously i have an error. Over the Not Nothing I have the following error: 'Is' requires operands that have reference types, but this operand has the value type 'Integer'.Is the type 'Integer' at the end there refering to the Nothing being an integer -1 or 0 and i'm not sure how i would reference the type active x.my question: How can i check if the activeX component is an activeX component and not a whisp of thin air/nothing.
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Feb 3, 2011
Here's what I'm looking to do. I have an array of objects that all implement a particular interface. What I want to do is search that array of objects for a particular object type.I have to do this in several places, so I'm trying to create a function where I pass in the object array and the type that I'm searching for, and have that function return the object that matches that type - or nothing if no match is found.I wrote the following, but it isn't working, so I'm missing something:
[code]...
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Mar 28, 2012
I've got an issue with a program I am writing. The specific issue is replacing characters in a parent string by finding, and matching, specific characters within it that are parsed from an external xml file. It's for a chat-like client.Here's the 2 classes I am using to pull the emote strings, titles, and id from external XML:
Imports System.Text.RegularExpressions
Imports System.Xml.Serialization
Public Class emote
[code].....
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Feb 10, 2010
My quest is in regards to xml serialization. I need to get rid of the root node of a collection. I don't have access to my source now so I'll just try to generalize
public class SomeClass
'...some other properties...
<XMLArray(isnullable:=true), _
<XMLArrayitem(datatype:=(getType(object1)), _
[code]....
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Mar 7, 2012
I have a hashset (of posdata), pos data containing a boolean and a label containing the hashkey. I need to draw up a condtion where it will check that if a boolean for two or three different records does not equal to false. And if the condition is true i want to set the boolean of the two or three records to false. Here is an attempt,
ElseIf (position.strLabel = "b2" And position.blnAvail <> False) And (position.strLabel = "b1" And position.blnAvail <> False) And (position.strLabel = "e1" And position.blnAvail <> False) Then
[Code]....
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Nov 9, 2011
I am having problems with my code, where I get the "Object cannot be cast from DBNull to other types" message when Insert(). I get the message on every Insert to this table, even though the data is successfully inserted. If I Update the same data after Insert(), it does so without error. I have checked my values and none of them are DBNull. Even when the same values are passed on Insert that are passed on Update.
My code is :
Private Sub Save()
Dim bo As tbl_GL
bo = New tbl_GL()
bo.ConnectionString = AppConfig.ConnectString
[Code] .....
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Jul 6, 2009
I have a statement that will call a Sub.
Charts(CurChartNo) = Server.CreateObject("ChartFX.WebServer")
Call InitChart()
Inside this sub, I will assign values to the properties of the Charts object that is
Public Sub InitChart()
Charts(CurChartNo).RGB2Dbk = &HC0FFFF&
Charts(CurChartNo).Chart3D = False
[code]....
But the Charts is not recognized in the Sub. This is current program under ASP, I am converting to ASP.Net.
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Feb 21, 2010
Is there a way for an object to call the object that contains it, like how a FrameworkElement has a Parent Property?Bill Gates look out!
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Feb 15, 2011
Given a list of objects, I'd like to print a string version of them just in case the object.ToString() result is a relevant string.By that I mean I don't want to get things like:
obj.ToString() -> System.Collections.Generic.List`1[MyLib.Dude]
obj.ToString() -> System.Collections.Generic.Dictionary`2[System.Int32,System.DateTime]
obj.ToString() -> System.Byte[]
But I want to get things like:
obj.ToString() -> Hi
obj.ToString() -> 129847.123
obj.ToString() -> Id = 123
What should be the best way to implement this in a method:
Public Sub PrintInterestingStuffOnly(ByVal coolList as Ilist(Of Object))
For Each obj in coolList
'insert solution here
[code].....
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Apr 17, 2012
I have a the following Class structure. Company > List(of Departments) > List(of Employees) I want to Query a Company to find out if it has a department of the following name and a Employee in that department with the following ID! How could I query this. The way I have the code it expect to return one department so I have it doing
[Code]...
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Jan 1, 2008
I have set my datasource on my datagridview to be a subset of rows as follows:
dg.DataSource = myDataSet.testTable.Select("id=" & id)
But I get a runtime error that Operator '=' is not defined for types 'Object' and '1-dimensional array of DataRow' There should be an easy way to do this that doesn't involve creating new tables, etc.
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Mar 22, 2010
i have a list view that contains files i use a for statement to go with them to and check what format the file is then sets its image but i dunno how to get it to work i cant use the or statement it says it cant convert to boolean
vb
If Label1.Text = "doc" Or "docx" Then
oresults.ImageIndex = 14
ElseIf Label1.Text = "ppt" Or "pptx" Then
oresults.ImageIndex = 10
End If
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May 14, 2010
I am currently using the following code to parse a webpage.
CODE:
Where it has:
CODE:
It would work, as with this:
CODE:
But i need it all in one line of code..
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Jul 7, 2010
I am trying to figure out how to check a string can contain a certain value.In the begining I had a checkbox and wanted to hide a ceratin field depending upon which checkboxes were selected.The problem with this is that the value is always = to the first value.
I got around this by writing these values into a hidden textBox and using a loop.So now I have a textbox and if the user selected the 1st and 3rd choice the textBox would = "AC" If they selected all choices it would = ABCD etc...How can I determine if the values in my textBox contains just letter 'B' ?
I tried this:
--------------------------
Dim values As String = [String].Empty
For Each item As ListItem In section2List.Items
If item.Selected Then
[code]....
but this doesn't work.
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Mar 2, 2010
I understand that an array variable contains a reference to an array object - it is a reference type. string variable is also a reference type. So, if I make a copy of either one, a change to the copy should also change the result I get when I look at the original because both refer to the same object. In the following code, I expected to see "Whoooy" as the result for original and copy for both the array and the string. It works with the array but not the string.
[Code]...
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Jul 7, 2010
I'm trying to create a sql query to search within an Access table that is showing inside a datagrid.
The search criterias used in the "where" bit are retrieved from info entered by the user in 3 textboxes and 1 DateTimePicker control. The first 2 fields are String type, the 3rd field is a date type (entered by the user using the DateTimePicker) and the last field in the DB table is Integer type.[ode]...
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Jun 17, 2009
If Double.Parse(list_numbers.Item(i), possibledouble)
list_numbers is a list of strings
list_numbers.Item(i) = "0.000"
possibledouble is a double
debugger returns "input string was not in a correct format"
i thought that the double parse would convert the string into a double format of "0.0" but it gives me an error.
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Dec 21, 2011
i have a textbox in a calculator and i want an if function so that it checks that there cannot be 2 .'s in it:[code]
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