Prevent SelectedIndexChanged Events From Being Thrown?
Jun 14, 2012
I have a combobox in winforms, which, depending on what you select, determines what's populated in other comboboxes. I filled the initial combobox using a dataview:
combobox_process.DataSource = dataview
combobox_process.DisplayMember = "UserDefine1"
combobox_process.SelectedIndex = -1
Which works fine, except every one of those lines throws the SelectedIndexChanged event. The function that populates the next combobox listens for that event and so it's running three times. I asked a coworker and he suggested just looping through the data and adding them all manually as strings, but I'd prefer to stick with databinding if I can. Especially if, in the future, I need to do something that I can only do with databinding. Perhaps some way to disable that event during a portion of this code?
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Apr 25, 2012
I am trying to programmatically add an unspecified amount of new UserControls to a form. One will be added every time an entry is selected in a ComboBox contained within the UserControl. Problem is, the SelectedIndexChanged event fires completely erratically. Sometimes twice, sometimes 3 times, etc., but never just once. No matter how many times I set the combobox's SelectedIndex to -1, it fires at least once with a SelectedIndex of 0. Sometimes the Itemselected event fires multiple times inbetween SelectedIndexChanged events.
InvoiceEntry.vb snippet:
Public Event ItemSelected As EventHandler
Private Sub cboItem_SelectedIndexChanged(sender As System.Object, _
e As System.EventArgs) Handles cboItem.SelectedIndexChanged
RaiseEvent ItemSelected(Me, EventArgs.Empty)
End Sub
[Code] .....
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Jan 27, 2011
In the context of data-bound combobox whose ValueMember and DisplayMember properties are appropriately set:Is there a difference between the SelectedIndexChanged and the SelecetedValueChanged events? Are they fired simultaneously when an item is selected from the drop-down list of the combo?
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Oct 29, 2010
I noticed that the BeforeNavigate2, NavigateComplete2 and DocumentComplete events are not thrown by SHDocVw.InternetExplorer if the user clicks the Refresh button. I need to handle all of these events when our users navigate to various links.
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Jan 5, 2011
I've a control that throws an exception in one of its events and I need to catch this exception. How can I do this?
Example:
Private Sub AxNtlxImage_Reason(ByVal sender As Object, ByVal e As AxNTLXIMAGELib._DNtlxImageEvents_ReasonEvent) Handles AxNtlxImage.Reason
' TODO: Deal with this reason message
Throw New ArgumentException(e.sText)
End Sub
I want to catch this exception from another procedure when it happens.
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Sep 7, 2010
I need to handle events that are thrown by Internet Explorer 8. I am able to handle events associated with the first tab that is created when IE8 launches, but I am unable to handle events if the user creates a new tab or opens a new window. I need to handle events of all tabs (and preferably all new windows as well) that are created by the instance of IE8 that is launched by my application.
[Code]...
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May 13, 2012
This may be a debugger issue, but here goes:I have this piece of code:
Private Function Connect() As Boolean
Try
sessionBegun = False[code].....
My intention is to 'convert' the low level exception into something more meaningful, so I throw an exception of my own creation. I want this to bubble up to a place where I can handle it.However what is happening is my debugger breaks and tells me that an exception of type "QuickBooksConnectionException" was thrown.I know that, I just threw it, why are you catching it? From what I've read, this ought to work, and there doesn't appear to be an analogous Java throws keyword, so perhaps it is my debugger.
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Jun 30, 2010
Consider a simple VB.NET form with a couple of radio buttons and a checkbox.
Each of the radio buttons has a CheckedChanged handler setup that performs some action based on the state of the checkbox.
My problem is, when I initialize on the default radiobutton to be checked (from the designer properties window) the CheckedChanged event is fired for that radio button, but the Checkbox hasn't been initialized yet so I either get a null pointer exception or the wrong value is used in the handler. Either way, I don't want that handler code to be run unless the user picks a radio button after the form has been loaded.
I currently get around this by not initializing the radio button, but I need to set that default eventually and the best place is from the designer. I also can add a boolean field that's not set to true until the form is fully loaded and not process the events if that is false, but it's a dirty hack.
What can I do to prevent that handler from running its code?
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Nov 17, 2011
I have a VB.NET application. When Texter or PhraseExpress is installed and enabled, the program behaves poorly. Debugging has revealed that at times I can press Enter in a field and no event will be fired (i.e. no breakpoints in the event handlers get hit), then I press it again, and they will be fired twice. (Basically these cycle if I keep pressing enter - one time nothing will happen, the next I get two events, the next keypress does nothing, the next triggers two events, etc.)
Since Enter is used in certain places to trigger searches, or to move between fields for fast data entry using the numeric keypad, this effectively breaks the program in these spots. The problem is highly repeatable - disabling Texter or PhraseExpress causes the program behaves perfectly normally. Enabling them again causes it to break. Note that in both text expansion programs, I have assigned NO events to the Enter key. In fact, with Texter (haven't done this particular test with PE yet), it happens even if NO replacements have been defined at all, simply based on whether Texter is enable or disabled.
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Jun 8, 2012
I have a few reasons that I need this to happen, but suffice it to say that when I use the event handler for the RadioButtonList the sender object returns as just the RadioButtonList, and I need more information from the GridView because that's how I can uniquely identify which record my RadioButtonList is tied to.I added an "OnSelectedIndexChanged" property to my GridView but it doesn't fire/handle when I want it to. I'm assuming this has something to do with the way the GridView is designed to work. I also thought about using a hidden field, but I can't add it to the RadioButtonList so it won't help unless it's global. The problem with it being global is that I can't set the value uniquely to the record that has it's RadioButtonList being altered.
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Feb 13, 2012
What I want to do here is that for every new item added into the combobox the label will +1 from the previous number. How do I write it out assuming I didn't assign the items a number [Code]
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May 13, 2009
Why would this event only work once, the first time I select an item? If I select another item off the list nothing happens.
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Jan 29, 2010
I have a combobox which is bound to a bindingsource.
What's the correct way to get the combobox selectedvalue on the selectedindexchangedevent?
is combobox1.selectedvalue correct or must I use the bindingsource to get the value?
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Jan 11, 2012
I have a GridView, without using SelectedIndexChanged, how can I retrieve the value of each row from GridView when click on each button in each row?this is my aspx code
[Code]...
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Sep 29, 2010
I have a situation where I'm allowing users to enter new values into a combo box or selected existing values from the combo box's drop-down list. Is ther any way to tell whether a value was entered or selected? I've looked at the TextChanged and SelectedIndexChanged events and neither will do what I need to do.
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Nov 24, 2010
I am using VB 2010 express edition, using windows form, i set my access database using the database connection wizard, and then use a combobox and bind it to the database using the properties windows, while other fields of database (set in textbox form), i drag it to my form. Running it, the values of textboxes are correct when i changed the value of my combobox. I want to use these values in textbox in drawing circle, whenever i change the value of combobox, the circle will also change using the combobox selectedIndexchanged event, my problem is, the value in textbox does not update in order to draw the circle, i have to use lostfocus or leave event to correct it. I make also a combobox and textbox not using this Ado.net(correct me if im wrong), it is working using the selectedindexchanged event only, what seems be my problem,
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Jul 31, 2008
On a form I have a DataGridView. Inside this DataGridView i have several columns of which one is combobox and the others are textboxes.The combobox column is populated with values from a MySql database table using a query. So far so good. What i want next is to populate a certain textbox from that DataGridView, automatically after a value from the combobox is selected. When a value is selected from the dropdown list of the combobox, that value is used in a SQL query to find the value that will be displayed in the textbox.All the textboxes and the combobox are inside the DataGridView!)I did this using DataGridView EditingControlShowing event because a DataGridViewComboBoxCell does not have aSelectedIndexChanged event.The value is displayed correctly in the textbox, but the problem is that the value selected from the combobox disappears after the selection, and the combobox remains empty. I need the value to remain in the combobox after it was selected and after the corresponding value was inserted in the textbox!Here is the code for this:
Code:
Private Sub test_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Populating the combobox
[code]....
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Feb 16, 2010
I have combo box selectedIndexChanged events going on but I cant figure out how to get the value out of them so that when i hit the btn_ProjSal that the new salaries show up in the 3 labels. Here is my code. Doing it straight from the selectedIndexChanged event this works..but to get the button to pull the new values from each of those events is my issue.
Public Class Form1
Dim _emp101Sal As Decimal = 10000.0
Dim _emp102Sal As Decimal = 11500.0
[code]....
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Mar 3, 2009
For some reason I have always used the SelectedIndexChanged property to take action when something is clicked (I guess because this is the default property? ie when you double click the listbox this is what you get). However I have often come across problems when I try to unselect all the items in the listbox by calling
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Dec 15, 2009
Here is the basic problem. When a listview is set to multiselect = true, the electedIndexChanged event fires for every row. This is very bad in a situation like the following psuedo code:
MultiSelect in listView (many items)
Clear any items that are selected in GridView
find that item in gridView using a brute force compare
[code].....
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May 17, 2011
.net 4.0, ASP.net, vb.net. I've got a usercontrol that is using an obout combo box. The obout is a cascading combobox that has 3 levels to it. when something it selected from the third level of the combobox, it is suppose to fire off a selectedIndexChanged event. This happens the first time that I select the usercontrol. The problem is if i want to go back and select something different. The selectedIndexChanged doesn't fire. I've set breakpoints and the AddHandler ComboBox3.SelectedIndexChanged, AddressOf ComboBox3_SelectedIndexChanged
runs just like it did the first time i select the usercontrol. But the selectedIndex just doesn't fire the second go around. Was wondering what i'm doing wrong. Here is the selectedIndexChanged that is not firing
[Code]...
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Mar 11, 2011
I have a datagrid view on a page that I'm making and I want to be able to open another form when a user "selects" an entry. I've tried looking through the documentation on how to do that but can't seem to find any. Does anyone know of an easy way to accomplish this task?
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Jan 29, 2009
I have two listviews with many items present. When the user clicks an item in ListViewA, I highlight items in ListViewB. I use the SelectedIndexChanged event of A, loop through the items in B and set some highlighting colors, ensuring visible etc. This works fine.However... it would be nice to allow the user to MultiSelect. The problem here is the when selecting 10 items in A (holding the shift key down), the SelectedIndexChanged event fires 10 times, once for each item added into the selection. This is a real pain since my highlight sub then runs 10 times and it takes 10 times as long.Now... I had a plan to deal with that, I detect the shift key being held down and inhibit the event until its raised. That works fine too.But... if I have 10 items selected, and then I click one new one, so 10 are being deselected and one being selected, the SelectedIndexChanged event fires 11 times. So my situation has not improved. Any ideas how to wriggle out of this?
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Oct 13, 2011
I have been trying to implement the jQuery weekcalendar using .net. What I can't seem to figure out is why weekcalendar states events.events is undefined after I make an ajax call to a webmethod I created which returns JSON. Below is the relevant code:
[Code]...
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Aug 2, 2009
I want to make Keybord events and mouse events for learning and educational Purpose.
1. In Form any object like A "picture box" move by Arrow keys .
2. Picture Box Contain many Picture i want change Picture With next and Previos By Arrow keys.
3. I contain Voice of alphabet in Mp3.When i Press any button in textbox then its work.
4. Mouse Pointer Change My Own.
5. I click any Object or any thing By mouse its noice clicking sound like Tik Tik Tik.... Question No 3 is very hard to do . but not im possible
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Nov 2, 2010
I have added the AutoPostBack = "true" attribute to the drop down list. It doesn't work.
<asp:DropDownList CssClass="dropDownList" ID="ddlBusinessUnit"
AutoPostBack="true" runat="server" Width="250px"
OnSelectedIndexChanged="ddlBusinessUnit_SelectedIndexChanged">
[Code].....
How can I ensure that the event method is called?
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Apr 13, 2004
I have a ListView that populates some fields whenever the user selects an item. However, if they change the data in the fields and then select a new item without saving, I want to display a message box that warns that their changes will be lost, and asks them to confirm whether to continue. Sounds simple.
Unfortunately, the ListView's SelectedIndexChanged event cannot be cancelled, and it's actually called for each change in the selection. So, for example, if item 1 is selected and the user then selects item 2, the event is called twice: once to remove the selection of item 1, and then to add the selection of item 2. If you go from having one item selected to having five (for example), the event fires to remove your original selection, and then again for each of your new selections - six hits in all.
Obviously, this makes it a bugger to determine when the event should be cancelled and reset back to the original. I obviously don't want my message box appearing six times....
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May 21, 2009
I have a ComboBox that contain ProductIDs and a DataGridView that lists Categories which a product can be a member of. My DataGridView list ALL categories, however, it has a checkbox column that get checked when the ProductID is a member of that Category, otherwise it is unchecked. A user may also check or uncheck a category checkbox then save.
The problem is, if a user forgot to save before changing the ComboBox, then his changes on the previous ProductID is gone How can I give the user a chance to either save or ignore the changes done on the previous ProductID (before selecting a new ProductID)?I searched the internet for an answer and I found the following code but it is in C# and I am not sure if it solves the problem or not!
[Code]...
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May 6, 2011
I have been looking for a solution to this for a while though and seen many posts that show me how to do it but yet I cannot get my SelectedIndex Changed event to fire when the DropDownList is changed.The DropDownList AutoPostBack is set to True,[code]
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Jul 5, 2006
What is the method to not allow combobox SelectedIndexChanged to be executed on load. and only make it to be executed when a "USER" changes the selection value.
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