Accessing Public Properties Of An Object Contained In A Listbox?
May 8, 2011
I have to make a VB project for one of my college Co-Sci classes. However, I am having issues doing what I think is logically possible. Part of our project entails creating a user defined class, then create a form that then instantiates an instance of the object type. After that we are to list the item in a listbox. That is all well and good and works fine.
What I need help with is looping through each object in the listbox, getting some data from the object, then moving to the next.
I have been trying something similar to c++. For example, an object contained in a c++ array can be accessed like this:
array[index].someObjectMethod().
How would someone do something similar to that for objects contained in a VB listbox? I imagine it starts something like this:
I am moving from VB to C#. I am trying to loop through a collection class which is a collection of data classes but I can't seem to get the actual values out of the data class properties(find the correct code to do so). I have a method that loops through the collection class(Contacts) and saves each record(Contact). I am using reflection because my method will not know if it is Contacts class or a Customer class and so forth. Here is my code in VB(watered down)
Public Function SaveCollection(ByVal objCollection as Object, ByVal TableName as string, ByVal spSave as string) Dim objClass as Object
[Code]....
The C# code keeps returning null. In my locals window I can see the proprties on the class on objClass and the value of the propery but I can seem to figure out how to access it through code. I used the DictionaryBase because that seems to closely match would I need to do. My data class(Contact) has a bunch or properties that match the field names in the database of the Contact Table. After I get the propInfo variable set I then set up my SQLParameter with the fieldname, datatype etc and then set the value to the propInfo.value.
at some points, I need to call the same method on those controls (ex. user presses the clear button on the big control, I want to call the clear f(x) on each of the controls)I thought to toss the controls in a collection, and then be able to handle them something like this: nextturns out, and I should have realized, methods and properties of controls are not exposed when treated this way. The only thing that can be seen is the stuff that the base class (control, I guess) has.
dim l as List(of MyClass) = new List(of MyClass) and I want to get the type of the objects contained in the list, how do I do that? The obvious answer, that doesn't seem to be possible from my actual implementation, would be to do something like this...
public function GetType(byval AList as IList(of GenericType)) as System.Type dim lResult as system.type = nothing if AList.Count > 0 then lResult = AList(0).GetType return lResult end function
But what if the list is empty and I still want to know the type it contains?
I am having some real issues with this one. I have a class which contains two other objects...but I cannot seem to instantiate those sub objects. Here is the code for my class:
I would love to implement the asp.net routing but i have a basic question.
In my Generic handler i have the following Global class
Public Class MyHandlerRouteHandler : Implements IRouteHandler Public Function GetHttpHandler(requestContext As System.Web.Routing.RequestContext) As System.Web.IHttpHandler Implements
I currently have two forms, and I need to share the value of a variable in one of them.
I declared the variable to be 'Public Shared', and assigned a value to it. However,
when I inspect the value it appears as 'Nothing'. Here is the snippet:
Public Class A Public Shared sVar As String = Nothing Private Sub A_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
I am using this example I found to learn how to load class files and access variables through them. This is in a file called Class1.vb in the App_Code folder (this is not an app project):
Imports Microsoft.VisualBasic Public Class my_class Public Shared Sub my_sub()
[Code]....
How could I access the vartest variable without using a session, since if this is accessed by multiple functions at the same time the variable can be overwritten I assume. Is it possible to go the other way, where a variable is sent to a class file?
I have created a public shared subroutine in a class file in asp.net 2 (vb.net) web site app_folder.The subroutine retrives some values from a sql database via an sql query and assigns the datareader field values to several variables The problem is I can't seem to assign the variables from the subroutine to the variables and textbox controls in the asp.net page I am calling the subroutine from. The textbox text value just appear blank.By the way, if I response.write the variables in the subroutine they appear populated by the sql data reader.
I am currently working on a project of "interpreting" C# into VB. The project involves adding images to a database, retrieving images from the database and presenting them in thumbnails. Right now I have the following Public Class with the Variable that needs to be assigned:
I was thinking about writing some VB 2005 code that would be able to open an excel file and keep it open while I do things in separate functions/subs basically just check boxes, so each check box is its own sub but HOW do I do that with out opening and closing the excel file for every check box sub, since every time I make a check box the sub comes up as private?
I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj Inherits baseObj Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
I am writing a class library to interact with a domain Active Directory. In my object model, I have the following: Domain; Organizational Unit; Group; User.
In my Domain object, I have an Entries property and an Add() method. public class Domain { // The ReadOnlyDictionary<TKey, TValue> is a custom wrapper over an IDictionary. public ReadOnlyDictionary<string, IDirectoryEntry> Entries { get; } public void Add(IDirectoryEntry entry) { Entries.Add(entry.Name, entry); [Code] .....
For your information, I implemented the INotifyPropertyChanged interface to ease my life, but I don't seem to find a way to make it work the way I want. Perhaps am I not doing things right somehow, as for the location of different methods, I don't know. How can I make my Domain aware of a change that occured within one of its Entries, so that the TKey value is also changed? That is wanted because one could possibly add an entry, change its name meanwhile adding a new entry with the "old" name of the actual within entry, and cause a conflict, etc. In the end, causing the test to fail. But I'd like to make it pass like it actually is. Is there another better approach or workaround?
In my Site.Master.vb file, I have a custom User object:[code]Now in one of the content pages, I want to be able to see if a user is logged in. I figured if the object u was declared in the Site Master, I could use it in the pages that derive from the Site Master. For example, I want to do:[code]
I've tried searching... a lot for the answer, but as I'm not too sure what exactly I'm trying to do I can't seem to find anything. I'm trying to write a dll in order to handle errors thrown from a vb.net app. In the dll I need several forms (I'm not totally sure if they can have forms - I'm a bit of a newbie when it comes to dll's) for which the user can type in their message about the error and submit it.
Within my application i have a PUBLIC customer class...
Public Class Customer Public Name As String Public Surname As String End Class
Then i decided to use LINQ to SQL within my application.After adding the MyDatabase.dbml class, errors showed up since LINQ creates public properties too
<Column(Storage:="_Name", DbType:="NVarChar(50) NOT NULL", CanBeNull:=false)> _ Public Property Name() As String Get Return Me._Name End Get
Here are some errors..'Name' is already declared as 'Public Name As String' in this class.'SurName' is already declared as 'Public SurName As String' in this class.
Ok. Thats logical. But what is the best-practice i should use in the future? I would not like to use the Name and Pluralization options mentioned in ScottGu's blog or rename the properties of my Customer class.
How dan I dynamically create some public properties on a custom webcontrol.
For example, web control has 5 TextBox controls. I need a public property for each TextBox control to be able to set a specific property of the TextBox control.
I want to be able to loop the controls in the webcontrol and create a public property for each TextBox control.
I am trying to create a Public Sub / Function that will allow me to pass certain variables into it and this will affect the output. e.g. DIV ID = InfoDiv CSS Class = "Warning" LBInfoMsg.Text = "An Error has occured" DIV Visibility = True or False
I would like to type something similar in the code behind page: InfoMsg(InfoDiv, "warning", "An Error has Occurred", True)
Public Sub InfMsg(ByRef MyDIV As System.Web.UI.HtmlControls.HtmlGenericControl, ByRef CSS As System.Web.UI.WebControls.Style, ByVal strMessage As String) strMessage = strMessage.Replace("'", "''") MyDIV.Attributes.Add("Style", "warning") MyDIV.Visible = "True" End Sub
Is it possible for one class to access an array of values within another class as a readonly property of the second class? All of the examples and references on class properties imply that one can only retrieve one value by calling a class' property.
I have an exceptionhandler function that basically just writes a line to a textbox on Form1. This works fine when being run normally but the second I use a thread to start a process it cannot access the property. No exception is thrown but no text is written to the textbox:
Public Sub ExceptionHandler(ByVal Description As String, Optional ByVal Message As String = Nothing) ' Add Error To Textbox If Message = Nothing Then Form1.txtErrLog.Text += Description & vbCrLf Log_Error(Description) [Code] .....
Is it possible to access a form's properties from a thread this way or would it be easier to write to a text file or similar and refresh the textbox properties every 10 seconds or so (Don't see this as a good option but if it's the only way it will have to do!).
If I have a custom windows service running on a server, is there anyway I can access the value of a property/variable within that service? For example, I would like to have a client vb program be able to "read" the value some variable from that service. A simple example would be the service would capture a boolean value of the success or failure of the last time it kicked off a process. I would then like to have a client windows app "connect" with the service and be able to read that boolean value.
I want to know the correct way to access an object that is stored as an object in another object...phew. Here is what I'm trying to do...
I'm creating a restaurant map and to keep things simple I have 3 classes -- cServer, cTable and cGuest. cTable has a property which should contain a cServer object eg
Public Property Server() As Object 'Called when the property is read Get
I'm trying to update a dependancy property in VB.Net 4.0 inside of an Async callback. I feel like I am doing this correctly but I'm still getting the "The calling thread cannot access this object because a different thread owns it." error. Does someone see a better way of using delegates in VB.Net 4.0?
Private WithEvents myObj as CallingObject Private Delegate Sub MyErrorDel(ByVal strError as string) Public Property ErrorMessage As String
[code]....
Whenever ErrorMessage gets set inside of DisplayError an exception gets thrown, even though I am using the dispatcher to call DisplayError.
I am trying to access MS/Word document properties without opening the file in Word. Right now I have an app that reads the document properties but it has to open the document in word. This makes it run very slowly and also makes it susceptible to crashing if the document is corrupted. In Windows Explorer, you can right-click on a word document file and select properties. The ensuing dialog box contains, in addition to the usual information, two additional tabs labelled "Summary" and "Custom" that correspond to the same tabs in the dialog box you can open from File/Properties menu in Word. I know windows explorer is not opening the document in word because there is no instance of word.exe in task manager and because it has no difficulty in obtaining this information from the file even when it cannot be opened in Word because the document has become corrupted.If anyone could help me figure out how to read custom and built-in document fields (properties) from the file without opening it in Word,
I have a bunch of private variables I've typed out and I want to put all of my corresponding Public ReadOnly Properties in a bunch below them.Is there some way of copying ten lines of
Private _myVar As String
and pasting in ten sets of
Public Readonly Property MyVar As String Get Return _myVar[code]....
I'm currently copying the whole bunch of variable declarations, Find+Replacing Private _ into Public ReadOnly Property then going line-by-line expanding the definitions and writing return statements.how to avoid all this nonsense in the future, as I'm developing on a virtual terminal server, and the input lag on my little copy/paste/type operations on the code is driving me up the wall.
