Why Does The Value Of The Textbox Object Change In A Collection
Feb 19, 2008
i have a collection wherein i store an object for example i have a textbox Object which have a text value = "TEST" then i store this on the collection then i change the text Value to = "SAMPLE" then i notice that the value of the first Text Object the is also change to SAMPLE...
What am doing is an UNDO function wherein i store the object state in a collection..why does the value of the textbox object changes in a collection
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Nov 1, 2010
I have written some code to generate 10*10 textboxes during run-time.the problem is; I don't know how to access / change them after they are created. after some googling, I found this code to show the text of ie box42;
MessageBox.Show(Me.Controls.Item("box42").Text)
but it gives an error (nullreference exception was unhandled) hereby the code;
For i = 1 To 10
For j = 1 To 10
Dim tb As New TextBox
tb.Name = String.Format("box{0}{0}", i.ToString, j.ToString)
[code]....
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Sep 27, 2011
In VB.Net is every ObjectCollection Zero based except 'Collection' object itself ???
Like if you have an ObjectCollection like attachments for a mail for example, which has .Count in it, then i have seen it is Zero based
But in case of the 'Collection' object it is 1 based. 'ie dim cc as new Collection.
I am just confirming this because you can't keep checking for each collection of objects if it is zero based or 1 based, because if you use the For...Next loop, then do we have to think always if it is
For iItem=0 to ObjectCollection.Count-1
-OR-
For iItem=1 to ObjectCollection.Count
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Jan 5, 2011
In an application I am working on I have created a product class which represents an inventory item. I have also created an inventory class which represents a collection of product objects. In the constructor of the Inventory class I load 4 products into a product collection. Each product consists of a code, description price and quantity.
[Code]...
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Mar 27, 2009
i have a user define object which i'm initializing with data from external datafiles.... the purpose of this object is to reduce the amount of disk/data access and processing required every time i need to add an instance of this object to a collection.so, whenever i add a copy of this object to a collection, i would simply reference the "base" object, and avoid having to process all the data and perform the conversion and so on...the issue is when i add the object
Collection.add(Base_Object, Key)
the collection ITEM is a Reference to the base object and not a copy.
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Oct 28, 2009
I can't figure out how to determine the type of an object in a collection. I want to do a For Each ... Next loop over the items in the DropDownItems collection of a ToolStripMenuItem. For those items that are ToolStripMenuItems themselves I want to take some kind of action. (The collection can contain other types of items, such as ToolStripSeparators). So I need to say something like: If Typeof(item) = ToolStripMenuItem Then .
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Aug 30, 2010
I'm trying to loop through a collection object in vb2010.The code was originally used in Vb6 The book said that I needed to code a NewEnumerator method first in order to be able to loop through my collection. I coded the following:
[code]...
It gives an error for IUnknown, staging that IUnknown is not accessible in this context because it is a 'Friend'.In the line in the function I removed the Set since it's no longer needed.The error message for this line is '_NewEnum' is not a member of 'Microsoft.VisualBasic.Collection'What are these messages and how do I fix this in VB 2010?m_colCourse is not a system collection.
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May 17, 2012
Currently, I have a listbox lstInventory where I have loaded some database information from a .mdb file. I am able to add new records, and they all display correctly.
Yet, I can't seem to retrieve or access any of the listbox items. (Not trying to reaccess database in here, yet). I am hoping to "Edit" an existing database record by matching it to the lstInventory's selecteditem property. Unfortunately, I am not able to retrieve anything (tried traditional CType(lstInventory.selecteditem.ToString, String) approach, as well as a debug.write approach (which I can't seem to display, even with a Listener-which is another issue in itself).
Furthermore, when I check the listbox.items.count property, it prints out as a "0" [using a messagebox.show()]
I have tried searching multiple forums, but found lots of "database into listbox" threads, and the MSDN website hasn't helped me yet. Do I need to know the collection's name (what would it's name be based on ?)? Or am I not converting the object into a printable/countable quantity?
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Apr 8, 2009
I have a class which extends HashSet(Of T).I am trying to evaluate some custom properties of this HashSet during execution and make decisions based on those values.
During debugging, I am pausing execution and adding a Watch on my instance of this HashSet.
The Watch only provides me with a view of the Count of the HashSet and the objects contained by the HashSet.How can I get the Watch to show me the other properties of the HashSet?
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Apr 11, 2010
I know you are going to lough about this , but I guess I deserve it ...I am sure I am doing something wrong , but I can't find it out ...I have created a collection , lets sayMyCollectionI have also created a class , lets call itMyClass
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Oct 18, 2010
If I declare my object at the beggining of my page class, and instantiate it in a dropdownlist selected_index change event. Shouldn't this object be available thru out the entire page and also persist thru a postback? I lose the object in my selected date change event in my calendar.
[Code]...
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Jun 8, 2009
I'd like to store a set of key/value pairs in the application settings of my ASP.NET web app, but I'm not finding a straightforward way to do that. For example, these two questions tell me that StringDictionary etc. won't serialize to XML and suggest that I'll have to roll my own implementation. But it seems like this should be easier to do; after all, web.config is XML and < applicationSettings> is essentially a collection of key/value pairs, so it feels like I'm missing something obvious. Given my specific case below, do I really have to roll my own serialization, or is there an easier workaround?
The web app in question is a basic contact form that sends email to different recipients based on the value of a parameter; e.g. [URL]...The goal is to be able add or remove recipients (or change their addresses) by editing the web.config file so that I don't have to recompile and can easily maintain different configurations in test and production environments. For example:
// I can use something like this for the sender address SmtpMsg.From = New MailAddress(My.Settings.EmailSender)
// And then just edit this part of web.config to use different addresses in different environments.
<setting name="EmailSender" serializeAs="String"> <value>webcontact@exampledomain.com</value>
[Code]...
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Jun 10, 2009
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.
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Feb 8, 2012
I like the PHP way of doing things but, it seems I am stuck with using a Collection of Object's to store/retrieve the data I need. I have my Collection loaded with my Objects's and the code to iterate through the collection, my problem is I am unable to retrieve the "key" as it would be called in PHP (I believe in this case it is actually the name of the object).
Consider the following example:
Dim xDoc As XPathDocument = New XPathDocument(fName)
Dim xNav As XPathNavigator = xDoc.CreateNavigator()
Dim sender As XPathNodeIterator
[CODE]...
As you can see, I am navigating an XML document, and creating an Object with some Key/Value pairs. The Object would look something like this if it were in JSON:
{"name":"John Smith","address1":"123 Anywhere St.","city":"This City","state":"FL"}
When I iterate though the Collection I can only get the value of the object, but I need the Key, in this instance I want "name","address1","city","state" to be stored in a variable for each iteration.
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Aug 12, 2011
I have an object with a property that is a collection. When I point the PropertyGrid to the object it displays the ellipses for the collection. When I click it I get the generic collectioneditor. Of course the Add put fails because my collection is strongly typed. I need an example of how to create a collectioneditor that will create my collection's objects.
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Sep 18, 2010
I am using LinqPad to learn Linq by querying the NetFlix OData source.Here is the query I got working which is awesome.[code].....
(Pardon all the comments...it is a testament to the fact I am experimenting and that I will change the query for various needs).There are two thing I cannot figure out.First.Let's say I only want to return the first 10 results.Second (and most importantly). I want to filter by a partial string of the genre.Each title contains a Genres collection. I want to show only Genres where the Name contains a certain string (like "Family").Even better filter using Titles where genre.name.contains "firstFilter" AND "secondFilter".Basically, I want to filter by genre(s) and I cannot figure out how to do it since Title contains its own Genres collection and I cannot figure out how to return only title that are in one or more genres of the collection.
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Oct 6, 2009
Datatable object within class function + garbage collection?
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Nov 5, 2010
Basically I have a simple while loop that loops through a datareader and saves the information into a object collection. Later on in the code I have a simple function that loops through the collection and exports the data to excel. The later part works flawlessly.OK the issue is that for some strange issue If I just let the while loop work as it should it misses records in the datareader stream. Now it sounds crazy but if i add a counter (x=x+1) along with a message box at the end of the loop to tell me the value of the counter (msgbox(x)) it ALWAYS saves the correct amount of records. If I take the msgbox line out it ALWAYS misses records. I am so boggled right now.[code].....
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May 4, 2012
I am attempting to write a Dictionary Collection to a file.The Collection is structured like so:
GlobalCollection (Collection of TestCollection)
(0)
[KEY]
[code].....
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Dec 4, 2009
Is there a way to change a base class type by Overrides or Shadows, or other meen?[code]...
In this example there is MyBaseClasswitch is the base Class, then ClassB that Inherits from MyBaseClass, and In ClassB I try to overrides the base property "MyColl" to change is type to a enum.
But it do not work, telling me that the base collection cannot convert to eCarBrand, blah blah blah
Is there other way to change base class type or other approach that a could use?
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Jan 23, 2009
If I use a single variable of type Excel.Worksheet to reference Worksheet1, and then change it to Worksheet2, Worksheet3 and so on, is it adequate to simply do "Marshal.FinalReleaseComObject(worksheetVariable)" once at the end? Or would I be left with some references still in memory? In other words, do I need to do a "Marshal.FinalReleaseComObject" before each re-assignment?
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Oct 27, 2010
I need to bind a textblock.text property to a single element in an observable collection, or array element, and have the text update using the INotifyPropertyChanged or INotifyCollectionChanged, whichever is best.
Most examples describe ways to bind listboxes or other list views to entire collections, but my application needs to update several textblocks on a screen depending on notification of a change in one or more elements of an array.
textblock1.Text = MyArray(0)...
textblock2.Text = MyArray(1)...
textblock3.Text = MyArray(2)...
textblock4.Text = MyArray(3)...
Is it possible to bind a single textblock to a single array element? Is it possible to get notification of the proper type that will update one or more of the textblocks if any assigned element changes?
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Feb 3, 2010
I have a theory that the CLR garbage collection mechanism means that I can get away with circular references in my object hierarchy without creating deadlocks for teardown and garbage collection. Is this a safe assumption to make? (Target language VB.NET)
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Jan 12, 2010
I have a group of boxes witch will all hold data input by the user. I am using an arraylist to store these, or atleast I am hoping to. So, the problem I have is getting the data to actually save to the arraylist. It keeps giving the error saying that type string cannot be converted to array list.
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Jun 30, 2010
I have made taken one textbox in form, in which i have written following logic in Got Focus event.
When i focus on that its automatically showing all the suggested name from database field.
Private Sub CustomerName_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles CustomerName.GotFocus
da = New SqlDataAdapter("Select CustomerName from CustomerMaster", myConnection)
da.Fill(ds, "CustomerMaster")
[Code]...
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Dec 15, 2011
I have a DGV I am working on, and I have many columns.
For example I have Columns colcase(Combobox), colreportTime(Time)
the combox shows 4 cases {A,B,C,D}
what I need to do is if the user select "C"
the the colreporttime will show the time of this change unless the old value is C
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Sep 21, 2007
Is it possible to have a texttbox autocomplete source set to a listbox's collection? I see:
FileSystem
HistoryList
RecentlyUsedList
AllUrl
AllSystemSources
FileSystemDirectories
CustomSource
in the texxtbox's autocompletesource property but are unable to make it happen.
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Aug 17, 2011
I am attempting to create a small script to help me build a photo inventory for a few thousand widgets. Each widget has a unique barcode. I'm working on a program to let me take a picture of the widget, then scan the barcode and use the barcode value as the name of the photo file (barcode scanner inputs text string wherever curser is positioned). Right now I have a script, which I put together from a sample available online, which lets me capture an image (.bmp) using a webcam, then it lets me save that file, using traditional Windows saving method (opens an explorer to select the location and type in the file name). It works, but I want it to work a little quicker, less clicks.
Imports System.Runtime.InteropServices
Public Class Form1
Const WM_CAP As Short = &H400S
[code]....
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Dec 2, 2009
whats wrong with my code?if i change the item from the combo box..the textbox not change or has an error?
conn = New MySqlConnection()
conn.ConnectionString = "server=localhost; user id=root; password=12345; database=gigzta; allow zero datetime=no"
strsql = "SELECT accNo FROM accinfo WHERE (completename LIKE '%" & ComboBox2.Text & "%')"[code].....
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Oct 20, 2009
I am considering a piece of code that will manage access to a collection object from multiple threads - add, update, remove, clear. OK ... so I have put a sync lock within each method, but what is not clear from the MS documentation is exactly how the sync lock is behaving. Is it locking the piece of code it wraps? Or is it locking the object? And if it is locking the object a private static object should lock out any code locked on the object within all instances of the object? i.e. if an add operation is underway, an update, delete or clear will wait for the lock to be released.
Finally, if I have multiple threads contending for the sync lock, how is the release managed? First come, first serve? random (from my p.o.v)? Is there a chance that two separate threads could blunder into 'locked' code simulataneously?
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