Value Of Combobox.Text Lagging Behind When It's Actually Changed?
Jun 15, 2012
Really weird issue, perhaps someone can shed some light. I have a windows form with a combobox. When you make a selection it's supposed to update another control, so I have
Private Sub LoadAssociatedLocations() Handles combobox_categories.SelectionChangeCommitted
Dim test As String = combobox_categories.Text I've done this in other winforms projects without issue, though for some reason in this case, when the combobox is changed, combobox.Text has the value of the previous selection. The SelectedIndex value is the connect index, but Tex is always the text of the previously selected index. I can just use selected index of course, but I'd like to know what's causing this strange behavior.
Well, I got some code below, but apparentally setting the Timer's to an interval of even 1000 (1 second) lags pretty bad,especially when both are checked, is there some kind of way to hook onto the memory so I know when the value is changed?What I think I have to do is likely hook onto all the characters that were there originally, +1 after in case the string changes only to get longer, and doesn't change the originally found characters.Then when a change is detected, then it will read again.I am simply trying to make the code run without lagging.
Public Class Form1 <Runtime.InteropServices.DllImport("kernel32.dll", SetLastError:=True)> Public Shared Function ReadProcessMemory(ByVal hProcess As IntPtr, ByVal lpBaseAddress As IntPtr, ByRef lpBuffer As IntPtr, ByVal iSize As Integer, ByRef lpNumberOfBytesRead As Integer) As Boolean
I am having a problem catching the event that happens when a user selects a value from a combobox. What I was using was ValueMemberChanged, but because I am populating the combobox in code during runtime using SQL and a dataadapter and dataset, this also executes the ValueMemberChanged event, so that makes it difficult for me to know when the user actually changed the value.
Now what I want to do is capture the event every time a value is changed in the combo box drop down (selectedindexchanged). When the index is changed, I want to grab the row number, and then I will grab the value of the now selectedindex and do some database updates with it.
I currently have tried to put together an event grabber when the combo box is changed, however it doesn't work correctly.
My code is:
Private Sub dgvRooms_EditingControlShowing(ByVal sender As Object, _ ByVal e As DataGridViewEditingControlShowingEventArgs) _ Handles dgvRooms.EditingControlShowing
[Code].....
I put in a message box to check that it was capturing the event. I then noticed that it captures it more than once when you change the value.
The problem is when I go to click the down arrow on the row, the event is run once (message box show). Then you have to click a second time (event is run again with message box) before it shows the drop down list.
Then when you click on the value you wish in the drop down box it shows the message box (the only time I want it to run).
Then when I leave that row, it shows the message box two more times.
Effectively it goes to update the data 5 times, I only want to do it once.
I can not there is a pencil editing icon when you click on a row to the far left, and it appears when you leave the row, after already clicking on your value, it then checks on row leave that the values havn't changed, hence it runs two more times.
How do I make it so it only runs once on the value being changed?
Is there a way to disable the pencil editing, but still enable the combo box column to work? (be clickable and choose an option)
When I have changed the name of a table field name none of my combo boxes or grid views work properly. The TableAdapter still refers to the original name. Is there an easy way to make the change propergate through the program or do I have recreate all my TableAdapters.
I have 1 Table Called "Menu" there are some textboxes and a combobox. I want to fill data in the Textbox called "Menu_Rate" on Selection of combobox selected item & coressponding rate of the Menu shoud be displayed in the textbox.
This is my Code con.ConnectionString = "Data Source=localhost;Integrated Security=true;Initial Catalog=Restaurant" cmd.CommandText = "select Menu_Rate from Menu where Menu_Name='" & cbMenu.SelectedItem & "'"
I have a content page which contains an UpdatePanel and has a combobox. When the combobox value is changed I want to change a label in my Master page. So, the main problem for me is that I don't want to make a full postback with every combobox value changing. Is there some trick to overcome full postback?
I'm Making a Simple syntax highlighter and I'm Doing the highlighting in the text Changed event of a RTB and for obvious reasons I can't re highlight the whole document each time someone presses a key so i highlight one line each time the text changes. But this creates a Problem. If someone pastes code into the RichTextBox It only highlights the last Line. So is there a way to get if the user typed the text in with his keyboard or pasted it from the clipboard in the text Changed event?
I added the colLocation to dgv."descirption" contains Unicode characters. I can see the comboBox correctly and choose the item.The problem is when the comboBox lost the focus, the value is changed to first item of the comboBox.
Updated:I found out that the ComboBox doesn't change the data when the DisplayMember is in English characters. It changes only when the DisplayMember is in Unicode chracter.
I have things set up so that the program is ready to start logging ,only when Recieving=true.This is controlled with Button1. So I click button1,Serial port is open and waiting for some signals from the Dyno.When 1 signal come it put a "1" in TextBox1 ,and for the second a "2" and so on. Thing is sometimes it starts right away, like I want it to,and sometimes it lags a fraction of a second, even though the Port is open.When it lags there are already 5 to 10 signals gone by before it starts logging 1,2,3,...and so on. Sometimes it don't start at all.Then I have to close and re-open the form and it works,but with lagging on the first "set"
"Textbox1 > 0 then" triggers a timer (not seen in this code)that samples Textbox1 once pre interval and writes the value to a listbox. On the upside as soon as a "1" is displayed in textbox1 the timer starts like it's supposed to.I noticed this behaviour before I added the timer and besides the timer has nothing to do with the signals coming from the SerialPort. I have my form setup so I can run "sets".Run one "set"...save...reset...run another "set" ...and compare.It's always the first "set" thats off.If I run multiple "sets" the first one is completely "whacked", and the rest are consistent.
Think this could be the SerialPort lagging,or code problems?
Public Class Form1
Dim resetValues As Boolean = False Dim RPM As Double
i wan to display the text from combobox into the textbox and clear the combobox text when click on the button.But when i select another text from the combobox and click the button, the textbox display and overwrite the previous text.How can i do so that when click, textbox display text from combobox and clear combobox text. Then click again, display the new text at 2nd line of the textbox without deleting the previous text?
I changed my Username on my computer from i.e. "xxxxxx x xxxxx" to "Dennis"
VB 2008 during a compile gave me the following error: Error reading icon 'C:Usersxxxxxx x xxxxxAppDataRoamingMicrosoftVBExpress9.0VSProjectApplication.ico' -- The system cannot find the path specified.
The file "VSProjectApplication.ico" is in 'C:UsersDennisAppDataRoamingMicrosoftVBExpress9.0'
Somewhere in the VB2008 "configuration" files I believe that I need to manually change the old path to the new path.
I found the old path in the ".suo" file. The ".suo" file is not a text file. How can I edit the .suo file, save it so that it will work?
on my Form I have a DataViewGrid and some textboxes with a save button (they are filled with additional data of the selected row).Save is disabled first, when I change something in the textboxes the save button is enabled.When the user changes a gow in the grid, I want to ask before changing the grid row, if he wants to save (if the button is enabled).I am using RowEnter but this is too late, then the selected row already changed (and my textboxes already got new data)...What event can I use to ask if I should save stuff before the user changes a row?Something like BeforeRowChanging with a chance to cancel changing the row?
I have a data entry form with many text boxes/combo boxes/controls. I want to change their bgcolor everytime the user makes a change so they are aware of what changes they have made before commiting.
My plan is to store the original value in the tag and comapre in the validated event.
I don't won't to write the same code everytime I need a control to behave that way. I've never written a customcontrol before.
how to achieve this by probably subclassing the control and reuse the code regardless of the type of control it is?
Is there a way to check if the user has changed the value of a textbox?I try to acces a variable in one of my methods to compare against the value but I can not seem to be able to access it?
I made an account manager where i can store all my accounts and I want it more protected, how can I changed the displayed text in my "colPassword" in datagridview? Just like in textbox the PasswordChar, please give me sample code :)
I have an number of text boxes and comboboxes on different forms. I have textchanged events which trigger a msgbox if the user enters invalid data(i.e. the number they enter is to big or to small). Is their a simple way to make the program not call the textchanged event when the form is loaded and the boxes get their initial value? Second is their a way to make the textchanged only be triggered when the user enters data not when the program clears the boxes?
how to trigger a textchanged event. I want to enter data in one text box and have the rest of the data show up after i fill it in. For example I enter someones name and then 3 other text boxes fill in with his height weight and ect after i entered his name.
I have 22 text boxes that have to be checked to see if the value has changed. I am using the TextChanged Event handler to do this thus:
Private Sub TextStringChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) DataChanged = True RemoveHandler ........
[code]....
The Handler would be added after the data had been loaded. The question is:Is there another way of checking for text changes without having to add and remove 22 handlers.
im trying to add a text changed method to my listview item. all the items are dynamicly created so i would think id have to use an addhandler listviewitem1.textChanged addressof listviewitems_click where listviewitems_click is the generic sub to handle the click. but the listviewitem control doesnt have a text changed event, but you can rename the text in the control anyway.
I have a tab control application, each tab loads a particular user control and each of those user controls will then add other user controls that are used amongst other the user controls. For example, I have an "ucQuotes" page and an "ucInventory" page, when the specific tab is selected, the "uc****" user control is loaded on that page, and in the case of "ucQuotes" and "ucInventory" they both use a control called "ucPartNumber"; a user control consisting of a combobox, textbox, and button. I have no issues reusing the shared user controls, in this case. My problem arises with my "ucQuickPrice" control, as it is always present at the bottom of the tab control form (separate from the tabcontrol, but on the same form), and it too uses ucPartnumber.
Here's my issue, as I type into the ucPartnumber combobox, the text I type does not appear in the combobox, it appears in the textbox of the ucPartnumber control that is being used on the tabcontrol page. There are no shared instances of ucPartNumber, nor do I have this issue between typing on one tab page and the text showing on the user control of another tab page.I tried just creating the ucPartNumber controls on the ucQuickPrice control, not adding a new instance of ucPartnumber on the .Load event, and the issue persists.
The combobox(s) in question are bound programmatically with about 40,000 items, ".datasource = dataset.tablename" not to a bindingsource. Autocomplete is set to none, I added code to utilize tool tips and the basic combobox filtering functionality. Is this a bug, or is there something I'm neglecting? I'm about 95% complete with this application, and this just happened today. I made the decision, to just reuse the ucPartNumber control on the ucQuickPrice control (originallly it's size and orientation would not fit, but I added some coding to detect what parent is adding ucPartNumber and to change its appearance accordingly). Before, I made this change, I did not have this problem. And, in trying to go back to how I had things set up before the change, the problem will not go away. if the whole control within a control verbage I used is a bit confusing, let me know and I'll try to better explain what is happening. At this point, I'm going to close and reopen vbexpress, as when I started this ordeal, vb started acting weird and wanted me to save all my work, it usually does this before locking up.
I'm in an upper level industrial engineering class in which we're learning some entry level VB programming. We're working on building a program to solve the travelling salesmen problem (finding the shortest path through a collection of cities while visiting each only once) and I'm trying to add some 'fancy' to it so I can learn some more skills. The basic program is designed to load a bitmap file of a map into a picture box and a text file with the xy coordinates of any city positions. From there, the user can plot the cities with red squares, draw a random tour through the cities, or tour the cities by always visiting the nearest neighbor not yet visited. The modification I'm working on is a method of pointing out a specific city with a black square by entering the city's number (determined from the coordinate file) into a text box.
Private Sub TxtFindCity_textchanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TxtFindCity.TextChanged Dim ObjFindCity As Graphics = picShowMap.CreateGraphics Dim City As Integer
[Code]...
So far, the program works, but I want the black squares (but none of the other graphics) that are created to go away once the text box is cleared. As of now they just hang around on the screen until I refresh the entire image with a 'clear map' sub. Any suggestions on how to accomplish this?
I am using the following code to populate text boxes based on a drop down list index change event
Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As WinControls.UI.Data.PositionChangedEventArgs) Handles DropDownList1.SelectedIndexChanged
[Code]....
The code works until it gets to the last item if there is only one item in the dropdown box it does not populate the text boxes, if I loop through the code it is going to the droplist index change but it goes from dr.Read() and just jumps to dr.close() without populating the text boxes?
When I will click the suggested text shown in the combobox it will disappear.My Combobox btw is connected in a database.If I type Kev then kevin and kevsky will show at its suggestion then when I will click any of it ,the combobox text will be empty or will clear what I typed ("Kev") and will not show what I clicked.[code]
