C# - DataGridViewComboBoxColumn Very Slow With Lots Of Items?
Sep 28, 2011
I have a DataGrid, with several columns. One of them is DataGridViewComboBoxColumn. I have a lot of items in this column - more than 1000 - and I need all of them. So grouping is not an option - all items must be there, users must be able to select from all.The problem is, DataGridViewComboBoxColumn becomes painfully slow, when number of items is about 1000, and above. This issues is well known to Microsoft, it dates back to Visual Studio 2005: [URL]...The problem is still present in Visual Studio 2010. Any ideas how to solve this?
Is it possible to fill DataGridViewComboBoxColumn with data partially? I mean (that was functionality fully working in Access), when you click DataGridViewComboBoxColumn, some items are displayed (lets say, 100 items). When you scroll down to the latest item, others are loaded (another 100) and so on. I don't see any other option to make DataGridViewComboBoxColumn working faster? Problem is, how to implement this? Has anyone meet that problem before?
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Sep 28, 2011
I have a DataGrid, with several columns. One of them is DataGridViewComboBoxColumn. I have a lot of items in this column - more than 1000 - and I need all of them. So grouping is not an option - all items must be there, users must be able to select from all. The problem is, DataGridViewComboBoxColumn becomes painfully slow, when number of items is about 1000, and above. This issues is well known to Microsoft, it dates back to Visual Studio 2005:Is it possible to fill DataGridViewComboBoxColumn with data partially? I mean (that was functionality fully working in Access), when you click DataGridViewComboBoxColumn, some items are displayed (lets say, 100 items). When you scroll down to the latest
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Feb 11, 2010
I've added a DataGridViewComboBoxColumn to a datagridview and it displays items ok but what I want to do now is have a default item selected, rather than show up empty or as a "Please select" message.
[Code]...
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Oct 11, 2011
My application is in VS2008 and coded in VB.net.
I have a datagridView(DGV) on one of my form.DGV contains a column of type DatagridViewComboboxColumn.I have another column of SrNo.
Consider Table1 to be the table from where my DatagridView is filled which contains following fields SrNo,Value1,Value2.
My requirement is i want to fill the values in my DatagridViewComboboxColumn from Table1.The DatagridViewComboboxColumn's combobox should contain values of columns Value1,Value2 of Table1.
Sample data of Table1
SrNo Value1 Value2
1 2 3
2 4 5
As data in datagridView is filled from Table1 the data of SrNo column of Table1 is also populated in one of the column of DGV.
Now my DatagridViewComboboxColumn combobox should contain the values of Value1 and Value2 of Respective SrNo.
Like Row one of my DGV has SrNo 1 as first value,so the Value1 and Value2 of SrNo 1 should be added to the row's DatagridViewComboboxColumn.
Select distinct Value1,Value2 From Table1 where SrNo=DGV.items(0,DGV.currentcell.rowIndex).value.H ope this Query willl make things more clear
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Oct 13, 2011
I have a datagridview with three columns which is filled using Datareader. There is a DatagridViewComboboxcolumn in the datagridView.
I want this DatagridViewComboboxcolumn should also be filled using datareader.
how can i add items to DatagridViewComboboxcolumn using Datareader. Below is the code that i have tried.
Here dr is SqlDatareader
Datagridview.Rows.Add(dr("Column1").ToString, dr("Column2"),dr("DatagridViewComboboxcolumn "))
But when i add this way im getting error on the DatagridViewComboboxcolumn Column.
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Sep 19, 2011
Using a DataGridViewComboBoxColumn, the goal is to make the ComboBoxes accept user's new items and also the possibility of choosing items that are already present.I'm aware of using EditingControlShowing event of the DataGridView to change the DropDownStyle of the DataGridViewComboBoxEditingControl at run time to allow this, but I'm wondering if this can be done at a lower level.
What I'm doing now is extending DataGridViewComboBoxColumn, DataGridViewComboBoxCell and DataGridViewComboBoxEditingControl, hoping to change the EditingControl's DropDownStyle in the moment I instantiate it. So far, no luck.The debugger shows the right assignment is being executed, but nonetheless, the DropDownStyle is popping at the EditingControlShowing (using the event for debugging purposes) as DropBoxList, not DropBox, which is the intent.
Here follow the classes:
Public Class DataGridViewComboBoxColumnALT
Inherits System.Windows.Forms.DataGridViewComboBoxColumn
Public Sub New()
[code]....
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Aug 10, 2011
I am trying to create a basic quoting tool but got stuck on how to clear and change the item collection from within a combobox for a datagrid.What we have is a list of 4 columns like a. Device b.TypeofService c.State d.Price Inside a sql database. Data is also structure like above as well.
I have a datagridview where the user will populate a,b,c and the price will be display and a total at the end. However a,b, and c aren't related in my current application. The combobox will show all possible dinstinct values for each column.
This works fine but I want to refine the application to only show the values of b. which are in the database after the user select the value for a. I have tried searching on how to do this as I assume to the Contry/State/City situation but could not find anything for a datagridview control in VB.NET.
Can anyone point me in the right direction? If I cannot do this dynamically from within a datagridview I was thinking of maybe creating three combo box outside and having it populating the datagridview afterwards but it wouldn't be as nice.
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Apr 2, 2011
I have a ListBox1, a Button1 and a DataGridView1 How can I achieve, than everytime I push the Button1, the items from ListBox1 will also reveal in the DataGridViewComboBoxColumn's dropdown menu.... I'm using Visual Studio 2010.
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Aug 5, 2009
Is there any good trick to speeding up a ComboBox when adding items? Even if I run simple test code, it takes about 10-15 seconds to finish...
Code:
For x = 0 To 3000
cboPeople.Items.Add(x.ToString)
Next
cboPeople is a combobox.
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Jun 12, 2011
I'm using Visual Basic Express 2008 to create an interface with a order database in MS Access 2007 (.accdb file). Everything is fully functional except updating the "Inventory" table is very slow. Updating around 2200 items takes almost 2 minutes and the window will appear as "not responding" for the duration if you click away and come back. Here is the process:1. Tab-delimited text file is picked by user, which includes all inventory items (not just new ones)2. Each line from text is parsed and read into variables (tempSKU, tempItemTitle, etc.)3. Old items are updated and new ones are added. -> This is the bottleneck
I used to have a series of IF statements to check which elements were changed and report them, but that was about 2x as slow. The new code is a little faster but doesn't provide the feedback I liked (update part is commented around):
Private Sub btnImportInv_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) andles btnImportInv.Click
Dim strName As String
[code]....
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Jun 8, 2012
I have a re sizable panel which i am adding over 100 buttons to. to do it i have a timer which detects any change in the height or width. then clears the panel and re draws all 100 buttons on. however i am encountering issues with flashing (where the buttons are gone for a split second before being repainted) and also speed issues. it seems to be slowing down the users ability to re size the window.
i was thinking by adding the buttons through its own thread it might combat the main (speed) issue.
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Oct 31, 2010
The data is loaded from a xml file (which the code parse the xml, and create datagridview cell dynamically). and the user is allowed to change the data, when the program exists, it will write back to the xml file to save the change.It works fine when there are not many rows. when it has too many rows, say, 10K rows, the program loads slowly. I searched, found some suggestions, but it seems they do not work very well.1) when load the data, not create the rows directly. instead, create a datatable, then add the table to the datagridview's data source. it still takes time for the dgv to show the data.
2) then, I guess maybe I should paging the dgv. then it comes 2 questions:2.a) I only have a manually created table, how can I get a dataadapter/dataset from it? do I have to put data in a database table first (i.e. sql express), then load it to data adapter? is it possible to manually create a data adapter/dataset?2.b) if I paging the dgv, does it mean I still need manually update the dataset/datatable to keep the possible change when the user navigate through the dgv? or, I can simply use an update method?
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Feb 13, 2012
I have a lots of strings.So I will need to do some statistics.The problem is some strings are the same.So,I will need to know the numbers of the same strings.How to do this.Shold I hold the strings in a Array of a List?
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Jul 24, 2011
I want to show lots of text in my form but i'm not sure how to do this efficiently.
The text is just instructions to the games Pong and Match so it isn't very long, but long enough to not be practical to type into a textbox's text control. The instructions will have paragraphs, but no other formatting.
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Dec 12, 2009
I have a form with lots of labels on it, and a reset button to reset them to a default text. This reset sub has lots of lines of code to get this done, but I think it cen be done in just a few. I thought of something like:
For Each Label In Me.Controls
Text = "0"
Next
but this doesn't work, or anything else that I've tried. how to do get this done? And what if I want half of the labels set to 0 and the other half to 1? Would that be possible without setting them all seperately?
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May 24, 2012
I'm creating a program which navigates through a tree-like structure. There are lots of items with a single 'parent' and many 'children'.
Using a SQL database, I've got all of the items information stored, but I'm struggling with how to hold the IDs for each Items children.
For example:
A: no parents, Children: B, C, D
B: Parent: A, Children E, F, G, H
F: Parent: B, Children: J, K, L, M
Where each item will have hundreds of children, for which I don't really want a column for each child...
Is there a simple (or more complicated) way to hold and retrieve a large number of integers within one column... i.e. as some kind of sub-database, or an array with the column??
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Jul 12, 2010
I'm considering making an application that will perform various tests against servers on a local network - for example pinging them, checking hard drive space, checking the state of services, whether or not databases are available, etc etc. Very similar to Hostmonitor if anyone has ever used that - but my app will be free
These tests would have to be performed at specified intervals, but the problem is that there could be literally hundreds of tests and I'm not sure how well my app would cope with hundreds of timers running... especially if they are all configured to run every minute or two (they all need to run independently of each other).
Really I'm just wondering how you guys would design such a system.The best way I can think of is to have a separate timer associated with every test and then when a test's timer has elapsed use the ThreadPool to do the work that the test will perform. That way if loads of them happen to run at the same time then the ThreadPool will queue them rather than trying to run say 200 at once. I also think I would need to have some kind of staging for when the app first starts, so that every single test is not going to have the exact same time to run (well, every test that has the same interval configured), but that shouldn't be too much of an issue.I guess it would be a good idea to try and use some sort of grouping so that more than one test can use the same timer - like if 20 tests were set to run with a 5 minute interval then I could use one timer and run all of the tests when that one timer fires.
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Mar 14, 2009
I am going to work with 300 000+ words... what is the best thing nowadays to put so much text so it can be searched fast (runtime)? I would use a jagged array but maybe there is something new since I read my last book with tips&tricks.
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Feb 15, 2008
I am in the process of writing a program that converts large number of records from one format to another. When doing some testing on it, to make sure I don't have any memory leaks, I am noticing a large number of undiposed cursor objects. I am not sure what to do with these. My program seems to run fine, however on some computers I am getting issues when the process is complete.
What happens is this. The program starts up, the user sets up the configuration options, it does it's processing, it creates a HTML report and launches IE (or whatever their default browser is) to display it. Then the program goes back to its Config display.
[Code]...
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Jul 20, 2011
how to go about changing the tooltip on 114 buttons. As you can see from the code below I need to change the tooltip information based on if there is data in an array of structures. I tried creating a string of the button name and passing it on but that did not work.
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim tooltipstring As String
[Code].....
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Feb 7, 2012
I have an App. I have a lots of datas to handle.So,I wonder if I can click a button and launch Excel and export my datas to Excel.So I can edit my datas in the Excel rather than in my App.
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Jan 15, 2012
How would I go about copying all the files out of a directory and lots of subdirectories and moving only the files somewhere else?(say C:Testfile1.txt).
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Jul 9, 2009
I seem to find more and more that I declare a lot of objects or methods as Shared now but it feels like I am not doing things properly.I try to avoid doing this but then I just end up with situations where I have to create an instance of a class just to call one method that would act no differently if it was just a shared method.Basically I'm just wanting to know if there is any good reason to avoid using Shared objects/methods. Obviously I dont declare EVERYTHING as shared, but it just seems to make things a lot simpler most of the time.For example in my current project (a chat application using WCF) I have a class just called Core which houses a lot of the main functions of the client program, so it has methods such as: SignUserIn, SignUserOut, SendMessage, MessageReceived etc and it also holds properties such as a list that contains all of the currently online users. These things are all declared Shared in my program because as far as I can see there is no reason for having to do this:[code]
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Jun 2, 2012
I'm a new programmer to vb.net, so apologise for what is likely to be ignorance.
I'm building a simple gui for a database interface, with many parent and child items within it. Upon a form I create buttons depending on how many items (parents/children). I've got the creation of the buttons thus:
For RowNumber As Integer = 0 To NoOfRows
Dim Buttoni As New Button
Buttoni.Location = New Point(LocationX, LocationY)
[Code]....
But I'm struggling with a way to delete the buttons to make way for a new set to replace them... I can delete a single one upon its click, but I'd like to delete all of the buttons that have been created in this way before re-creating them.
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Apr 6, 2011
I am completely new to Visual Studio 2010 and don't know anything about coding.I'm making a program that has lots of dialog boxes. When a user clicks Ok on the dialog, I need it to close the existing dialog box, and open another dialog I made, and so on. Does anyone know how to do this?I'm using version 10.0.30319.1 of Microsoft Visual Basic 2010. English version
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Nov 4, 2011
I have a gridview in windows form. When lots of data are loaded from the database to the gridview, my application hang until all the data are loaded to the gridview. Is there any way to solve this problem? I also want to display a gif image [loading.gif] or progressbar when data is being loading to the gridview to show the user that data is being loading to the gridview. But the image and progressbar also hang.
I have also one ToolTip, I want to display that tooltip in the center of the screen. My code is as follow but it is not positioning that tooltip in the center.
Dim x As Integer = TryCastInteger(Screen.PrimaryScreen.WorkingArea.Width / 2)
Dim y As Integer = TryCastInteger(Screen.PrimaryScreen.WorkingArea.Height /2)
ToolTip1.Show("It will take few seconds to display the data.", KryptonPanel1, x, y)
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Mar 19, 2012
I'm using ROUND() to calculate the value in one column from values in the others and it displays to a lot of decimal place.Its rounded correctly to 1 decimal place but when shown the the datagridview it displays like 12.3000000000..All 3 values used to calculate this one are stored to two decimal place, not that that should matter.[code]
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Sep 11, 2010
i am working on a project where i select from a list box what entry i want to change (out of a set of 27)and then i have to select the entry, enter the details in the text box, hit ok and then i was trying to make it store the string it made under a deceleration.
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Jan 31, 2011
My tile-based map editor project. So far, it works really awesome. Here, look at a picture: [URL] And the screenshot is outdated: Now I got the Pencil, Rectangle and FloodFill tools too!, the tilesets are from that popular (well, not so popular) game engine called RPGMaker.
Currently, this is how the map is structured:
One ArrayList represents the X coordinates.
One ArrayList in each X represents the Y coordinates.
One ArrayList in each X,Y represents the tile.
The tile is an ArrayList containing three elements:
The Image name (Tileset01 in the screenshot), the X coordinate in the image, and the Y coordinate in the image. Those coordinates are from the TILESET01 image, not map.
Getting the idea?
How do you locate a tile in the map when it is clicked?
First I get the cursor's position on the map picturebox, then convert it to a multiple of 32 (the tiles are 32x32, yes), divide the position X and Y by 32. The results are the indexes I need to get to the tile I clicked.
That method works just fine for me.
When the map picturebox invalidates and needs painting... When that happens, I iterate through each X and Y arrayList. When I get the arrayList that represents the tile, I use it to draw on the map.
For example:
Iterating X arrayList.... step 8......
Iterating Y arrayList..... step 3.......
Found arrayList with three elemetns: ("Tileset01",32,96)
Draw image on the map picturebox, source is "Tileset01" on rectangle (32,96,32,32)... draw it on map picturebox's point (8 * 32) and (3 * 32)
And so on.
Now you understand how I am working with my map editor, how I am locating clicked tiles, and how I am drawing it. Everything goes fine, except for one problem: At some point, the user might want to make a 500x500 map.
That means, an arrayList with 500 elements representing the X tiles. Then an arrayList with 500 elements for each X tile, representing the Y tiles. Then an arrayList in each X,Y pair.
Then multiply that result by 5, because there will be 5 drawing layers. How am I supposed to handle such huge maps?! My app explodes when I set the map dimensions to 500x500! 500x500 is the max setting allowed in my app. I also know that 500x500 map editors are possible, because I have seen others before. With great performance.
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Feb 4, 2009
i'm working in VB.net,i'm newto vb.net. i have Datagridviewcomboxcolumn in my project, i want open a form at run time it should open when i press F2 key onDatagridviewcomboxcolumn. but Datagridviewcomboxcolumn has no any events. how
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