VS 2008 Check To See If Item Exists In A List?
Jan 6, 2010
see if an object is already in a generic List(Of T) than the way I am currently doing it? The way I do it at the moment is like so:I have a method that I call each time I want to check to see if an object exists in the list (if it already exists I do not want to add it again) and the list to check is passed in to this method along with the item that should be added to it:
[Code]...
So as you can see this function just loops through the list that was passed in and if the DisplayName property of one of the items in the list is the same as the ProgramName argument that was passed in to the method as well then it returns True to indicate that this program is already in the list.I thought about using a Predicate with the List.Find method but cant see how I would get it to work because that predicate method will not have any way of referencing the list (its a method local list, not class level)
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Apr 30, 2009
This will check for an item in a listbox.[code]...
How do I check if an item exists in a listbox?
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Mar 2, 2012
The following code will save an item to file over and over again, but how do I save an item only once?
Dim w As New IO.StreamWriter("E:est.txt", True)
w.WriteLine(ListBox1.SelectedItem, True)
w.Close()
If, for example, number1 is already saved in the txt file then how do I not save it again, using something like the following?
dim exist As IO.FileAccess ("e:s.txt")
if exist.that.item.is.exist= true then
w.WriteLine(ListBox1.SelectedItem, True)
[Code] .....
I am using VS 2010.
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Aug 12, 2011
I'm having problem regarding session items. Before I use them, I want to check if they exists, but using this codes gives me error:[code]I think Session("SomeSessionItem") tries to acquire the value of the session item. If the item doesn't exists then it throws exception. But how do I check if a session item exists before using them? I have a page Home.aspx.In the Home.aspx.vb, I instantiate a WebUserControl SomeControl.ascx. Note that in Home.aspx.vb event handler Page_Load I can use a condition to check session without getting an exception.Inside SomeControl.ascx.vb I'm trying to access the session, here's where the exception occurs.
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Jul 14, 2011
I've been scouring the net, and can't seem to find a solution that works.I have a page done in ASP.NET (in VB) that has a drop down list populated by an SQL query.My dropdown list gets renders as follows (information slightly altered):
<select name="ddOptions" id="ddOptions">
<option value="--Select--">--Select--</option>
<option value="test">test</option>
[code].....
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Nov 3, 2011
I want to know if a string exists in the list of array ignoring case sensitivity
I have the following code working for my requirement, but its checking case sensitivity. How can use it ignoring case sensitivity...?
Dim SrtList() As String = {"abc","qwe","zxc"}
Dim chkStr As String = "abc"
If strList.contains(chkStr) Then
[Code]....
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Sep 9, 2009
I am filling a listview control with a big number of items but i came across an problem, the repeated values. In those items i use .Text and .Tag so i can relate some hidden values per item. I have been trying to use the items.find() with no luck since it looks like to search for keys, which i don't really have. Every item has different .Tag values but it can happens that they have the same .Text Is there any way to remove or just not add items based on a .Text search in the ListView?
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Apr 14, 2011
Is it possible to make one or more items in a checked list box collection non-selectable? I wnat to present the items to the user but not allow selection of them.
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Apr 14, 2011
I am using VS 2008 and MySQL. Which one of the following methods is efficient or a proper one to check if record exists or not before making an attempt to insert.
1. HasRows Property.
2. Select Where Exists
3. Select Count(*)
Or if there is any other appropriate method ( which i am not aware of ) available to do it in vb.net ?
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May 16, 2011
My form contains a combobox which contains several usernames which are bound to my database.I've added a checkbox to the form which will be used to select the default username from the list.
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Oct 13, 2010
I want to check if a refdes already been added to the generic list.And if so he must not be added..How do I do this I looked every where and can not fins a solution. [code]
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Sep 5, 2009
i want to check if a file exists in the Application.StartupPath. I tried My.Computer.FileSystem.FileExists but that checks the whole computer doesn't it. ? How do i check if a file exists in a directory?
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Sep 8, 2010
How do I check if an HTML element exists? This element will only "show" on a certain event. ex: numbers in a non-number textbox or something. I tried
If WebBrowser1.Document.GetElementsByName("ElementName")
But that won't work, because the element "is in" the HTML, even though the page doesn't show it yet.
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Jul 25, 2010
I've been trying to feed a multi line textbox into a string array then check item by item if a string contains part of it.
[Code]...
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May 14, 2012
I have a checkbox list which is filled with entries from my database on page load. I need to update an entry in my database when a item is checked and when an item is unchecked. Right now I am doing the following:
<asp:CheckBoxList id="check1" AutoPostBack="True" TextAlign="Right" OnSelectedIndexChanged="Check" runat="server">
</asp:CheckBoxList>
And the function:
Sub Check(ByVal sender As Object, ByVal e As EventArgs)
Dim sql As String
If check1.SelectedItem.Selected = True Then[code]....
The error is: "Object reference not set to an instance of an object." Is there a better way to check if a list item is checked or unchecked?
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May 15, 2009
LDAP check dir exists when authentication is none Experts I am try to check if an LDAP path exists and the following code works fine if the AuthenticationType is not none. How do you check this if the LDAP does not use authentication?
[Code]...
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May 5, 2010
i want to search item A (from a list of X items) in list B but i want to get the item not found example Search ITEM A in LIST B if not found then return a print....if found continue with ITEM B..and so on.
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Jan 1, 2012
I have a list box on the form which functions as a copy/paste. When you copy something, it is automatically added to the list box as a "clipboard helper". Here is the problem,however: if the text is more than 1 line, the list box does not show all the text.It ends up looking messy.So getting back to my question, is it possible to make the list box item height for an item depending on the amount of lines that item contains?This is a one line sentence in the list box and should take up one line.This is a multi line sentence in the list box and should take up two lines for item height.
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Feb 1, 2010
I have 2 listboxes on my form.Listbox 1 - populated with "available" field namesListbox 2 - populated with "selected" field names.There cannot be the same field name in both listboxes - it's either one of the other.The logic I was going to apply was to populate Listbox 1 with every field name ... and then as I populated Listbox with the field names which the user has already selected, remove the corresponding item from Listbox 1.
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May 10, 2011
I have a Menustrip in Visual Basic 2008. My question is how do I check only one menu item at a time? Lets assumed I have a MenuScript that is titled Fruits. When you click on Fruits, you get a drop down of four fruits. Apples, Orange, Bananas and Mango.
[Code]...
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Sep 25, 2010
I was wondering if anyone could show me how to check if a tag exists?Here is the code that I am using to get the information from the xml.
Dim XmlFile As New XDocument
XmlFile = XDocument.Load(WorkingDirectory & "ToolsMediaInfoMediaInfo.xml")
Dim Manage = XmlFile...<track>
For Each XmlTag In Manage
If XmlTag.FirstAttribute.Value = "General" Then
[Code]...
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Jul 10, 2009
This is the standard way of checking if URL exists [code]....
return true; } catch (Exception ex) { return false; } But my problem is that we have to check it for around 100 URL's. It takes more then 2 minutes to check for all as it is trying to get response of all of them. Is there any way that we can check if URL exists without getting complete Response so that total response time is less.
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Aug 31, 2009
I have a button that when pressed I want it to remove all the ending urls that have ending with / just to remove / item on the end so it will live me a url with out / on the end if u know what I mean. [Code]
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Jan 16, 2010
I have a list box that is custom drawn...I was wondering how i can get the rectangle for a specific item (not in the drawitem event) so that i can call (for instance):
vb List.Invalidate(GetItemRect(List, ListItem))
And it would just redraw that one item
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Jan 19, 2010
This is my problem, i have created a series of lists of stock items, i now need to remove items in one of the lists that exist in another list. simple enough except the quantity of stock is not necessarily the same so removing an object of the type stock wont work as they are not identical (stock amount not the same) any ideas on how to remove this item from my list?
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Jul 25, 2011
In my code, I want to check if a referrer url exists and if the referrer url contains a specific sub string. I know how to check for the sub string:
If( InStr( Request.UrlReferrer.ToString(), "some sub string here" ) > 0 ) Then
But I don't know how to check if a referrer exists or not. No refer exists if the url is entered in manually in the address bar. So I tried this, but this does not work:
If (Not (Request.UrlReferrer.ToString() = "")) And (InStr(Request.UrlReferrer.ToString(), "some sub string here") > 0) Then
how do check if a referrer exists?
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Sep 13, 2009
I have a windows service which fetches data from various datasources and build a XML file and send it to a webservice. For example first I will get customer details from Oracle Database and build the XML file and then the SQL Server database and build the customer details XML. I am planning to use the same function below to build the customer object irrespective of what the datasource is. But dr("age") column is not available in SQLserver datbase How can I check if a column exists or not.[code]
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Sep 30, 2009
I am trying to check if a folder exist, it doesn't work if the folder name has a space or "_" or "-". .
here is an example of cases that don't work:
"Folder test"
"Folder_test""
"Folder-test"
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Jan 29, 2010
I know how to make a new directory on an FTP server, but I wanted to know how I can check if a direcogtry exists, and if it exists display a message?
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Mar 17, 2010
I am using Caspol.exe to install a custom Permission set and add Code Groups for my .Net 2.0 Windows Application.
I have created a Console Application that uses caspol.exe to add Permission Set and Code Groups. I first install the Permission Set and if I do not get an error, I continue to install the Code Groups
Now sometimes I need to add a new Code Group to the client machine, so I make the changes to the console app and it is executed on the client machine. If the client machine already has the Permission Set installed, it returns an error and stops the further processing.
So, I want to know if I can check whether a custom Permission Set is already added or not?
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