I've got a VB2008 application that can potentially generate a table with up to 540 columns. The table is then used as the DataSource for a DataGridView. With column counts in the hundreds the processing time can by over a minute. With all this in single threaded Form code the UI locks up until the DataGridView is loaded. I've taken time stamps of the process to find out where the majority of time is spent.
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I'm learning some more VB in my spare time, and I'm making a simple customer database that uses SQLCE. I've got the datasource set up and all that, but for some reason when I hit accept on the form, nothing happens?
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I have setup a datagridview with one column as a combobox and bound to a dataset.
However, during runtime I want to refresh that column to show the changes. How do I do that?
I'm running some tasks on a BackgroundWorker thread and needed to display the current tasks in a label.Before adding the label, the tasks were completing just fine and the UI was responsive.Once I added the labels, the UI has become unresponsive. The issue, I believe, is the Invoke property.I've declared all my tasks, including the updating, in a sub and am getting the Invoke property of the label each time, in order to set the information.The following is an example of what I'm doing:
VB.NET
Private Sub Test()If lblTask.InvokeRequired = True Then Dim mi As New MethodInvoker(AddressOf Test) lblTask.Invoke(mi)
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i have lurked on these forums before and finally signed up..i have a situation that, after days of searching the web, i have not been able to come up with a solution for.i have to fire off a function that takes a large amount of time (writes to database, creates files, etc etc)this function is a non-shared function of a class. if need be i could make it Shared.[code]the code works great, but what i need to be able to do is update a form with a progress bar as the job is processing.all of the examples i have seen that do this are being called from within a Windows Form and they access the form directly - i cant do that in this case. my form needs to be 1 form for 1 job being executed - can process multiple jobs at one time and thus i need multiple forms.i have tried making the form part of my delegate class but since it runs in the same thread the effect is it "freezes" until the job is complete.i have just started looking into using a background worker but again, all examples i have seen use the component as part of a form - that wont work for me.
View 3 RepliesI'm using the following to check the state of checkboxes and then activate some public subs based on the checked state of the checkboxes:
vb.net
Public Sub TestSub() If Me.CheckBox1.InvokeRequired Then Me. CheckBox1.Invoke(New MethodInvoker(AddressOf TestSub)) Else Begin() End If End Sub
Within the Begin sub, I have code that performs specific actions and then updates a ListView with that information.As far as I can tell, the actions are being performed, but the ListView isn't being updated with the info.I'm calling the Test sub from a seperate form, within the BackGroundWorker's DoWork event.Would I have to check the InvokeRequired property of the ListView as well?I'm looking more into the documentation of the BackGroundWorker.
I have a goal to have dropdowns populate using a string array as the datasource. Re-binding works well in the dropdown event, but if I make a change to a currently selected line item it won't change until I make the box dropdown again. Is there a way to keep this updated without re-binding the data?
Also, this is one of several dropdowns on an MDI child form. I'd like to make sure they're all synced. For instance if one has "Bob" selected and I change Bob's name to "Chris" I need all the "Bob" dropdowns to change to "Chris". Is there a way to do that without having to cycle through all the windows and call a rebind function?
Finally, I want to know if there's a better way to do it than the way I'm doing it. Since all these children have to be synced, the MDI parent holds the String array as a public property and the children each leech off of it.
I have a wingrid that is bound to a datatable. I create a new asynchronous thread and from that thread make a remote server call passing the datatable. When the server call is completed the wingrid automatically refreshes to show any changes. However, since this is not being done on the main UI thread of the program, we will often get an error where the control goes whilte and a big red X appears in it.
Is there a flag to set the wingrid to not automatically upate when the datasource changes? I would like to turn it off before the remote server call and turn it on again after I am back on the main thread.
I am currently trying to develop an application which will backup large folders to a specified destination. To find all the files in the specified 'backup' directory I am using the following code.
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I have tried putting my GetFilesRecursive function into a separate background worker to run first so I can update the GUI however I am struggling on how to return the List of found files back to my application (I get cross-threading exception) and how to update the progress bar to show the progress of the GetFileRecursive function so the user knows it is processing the list of files and has not crashed/frozen.
I have several problems with rows in a DataGridView. Background information: The DataGridView (DataGridViewCalib) is in one TabPage of a TabControl, some columns of the DataGridView are automatically DataGridViewCheckBoxColumn as the DataSource have some colums which are Boolean. This is a Windows Form written in VB.Net with Visual Studio 2008. The user loads an input data file.
The problems:
1) At first arrival in the TabPage, ShowDataGridViewCalib (code below) is called. All rows are then shown in the DataGridView, despite the code saying that some rows should not be visible. Breakpoints in the code show that the code do arrive at the Rows.Visible = False events. Despite all rows beeing shown a Watch in the debugger shows that:
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There are two alternative ways of handling the rows in the code. The first attempt (commented away here) is probably the "nicest".
My application must display some data in Datagridview (status of COM ports communication) and i Used .mdb databases before for faster search and Datagridview update. How i understand Datagridview is importing data from DataTable and data in DataTable is imported from .mdb file, so i decided to make shortcut - stop to using .mdb file (data must be erased every time application start and it is useless make .mdb file and erase it every time, becouse it is increasing even when drop is used) and using only DataTable..
I want to row in Datagridview change it color to red when it's Collumn(6).text countains %error% string..
When Error in COM port is starting, i can fast find row in DataTable for that port and write information that Error accured for that port and DataGridview automatically updates:
Dim RRow as () DataRow
RRow = ds.Select("Port = 'COM3')
RRow(0).Item(6) = "Error Opening COM3"
I'm writing an app that pulls information from a DataSet as a one-way thing (e.g. the datasource populates a listbox, but for selection purposes only -- the user cannot change the list values). My problem is, when I select something from the listbox, all of the other listboxes change too, as if the control is telling the others "Update your contents to display what is in row 5"
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I then use the IDE to bind lstOne and lstTwo (both listboxes) to datInfo, and use the DisplayMember to bind lstOne to colOne and lstTwo to colTwo.When I run and click on a value in one listbox, the other one follows suit. For example if I click on "One Three" in lstOne, lstTwo displays "Two Three". I expect to click on "One Three" then be able to independently set lstTwo to "Two One"
This seems counter-intuitive, so is there a way to do what I'm after from the IDE, or will I have to do it all from code?
how to load data into datagridview using backgroundworker & progressbar?Let's say i have a report that shows some statistics, or has 100 000 of rows that should be displayed and during the load i would like to show the data that is already loaded and not to frees the form.Same example like in SQL when you perform a select command from a table which has 100 000 of rows and while loading the data, the grid is already filled up and progressbar is shown at the left buttom side.
View 7 Repliesi have a form and a datagridview in form i work with backgroundworker in here i want invisible a column in my datagrid i use delegate for it but i have error
Delegate
Sub SetDgvLastIssuedCard_Columns_Delegate(ByVal
[DataGridView] As DataGridView,
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When I try to change the datasource of my DataGridView, I am loosing the order of the columns and their type(checkboxes,comboboxes) that i specified on designtime! It's like changing the datasource is generating again the datagridview, why ? and How can I change the datasource without losing these information ? on form load i do something like
Private Sub frmGrid_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim Path as string
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I have created a Datagridview by dropping in from the Datasource. After I changed one column to be a Checkboxcolumn but it does not represent the values. In the table (smallint) I have 0s and -1s but it doesnt matter what I enter as True and False Value in the column it just shows that the box is checked.
View 5 RepliesI have a DataGridView and in it a CheckBoxColumn, when I click a cell of that column the check box gets checked.I do it like this:
dgvMessages.CurrentRow.DataBoundItem("have_read") = 1
but the change does not get committed to the DataSource (or at least not immediately), so when I search through it I get wrong results.
I can't call AcceptChanges as that will refresh the grid and cause unwanted side effects... What can I do about this? Is there such a thing as an 'AutoCommit' property on a DataGridView?
my question is, is there a way to filter records in the dataset and use that records to fill in the datagridview? for example, a datatable (with 3 columns: ID, StudentName, Gender) is filled with list of students. i have two datagrids in the form namely DatagridView1 and Datagridview2. DatagridView1 is where the the list of student where Gender is equal to M and DatagridView2 is where the the list of student where Gender is equal to F.in my current solution, i am using a loop.
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is there a way without using a loop?
I simply cannot understand or see when a DGV's DataSource (a DataTable in my case) get's updated when a new row has been added to the DGV by the user. I have looked at row counts in the DataTable at every possible event and cannot "get" the correct number of rows (which I ultimately need to "get" the GetChanges(DataRowState.Added) of the DataTable.So, here's what I've done.1. The DGV is populated on the FormLoad event. It includes a ComboBoxColumn which has it's own datasource. All fine.Now, let's say initially there is 1 single row in the DGV. There is also and "empty" row at the bottom of the DGV, all cell values are empty.if the user Clicks the ComboBoxCol and chooses an item, then this actually creates a NEW friggin' row, RIGHT?!No. Not exactly. At least NOT in the DataTable (The DGV's datasource).I attempted to "check". Looked at the editingComboBox_SelectionChangeCommitted event:
Private Sub editingComboBox_SelectionChangeCommitted(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles editingComboBox.SelectionChangeCommitted
Dim rct As Integer = ImprovementsEntity.improvementTable.Rows.Count
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I have an app that has a DataGridView with a few buttons. My intent is to have the DataGridView populate with the data associated with the button clicked. So if you click the States button it'll fill the DataGridView with the DataSet I have created with a link to a SQL table with a list of States.
View 7 RepliesWhat is the best way of quickly loading a datagridview with thumbnails of images and filenames/paths found within a particular folder using a backgroundworker without affecting UI performance ?
While loading, I'd like to continuously filter the dgv's image column through a textbox to display results as the user is typing.
how to safely load a datagridview via a backgroundworker while showing progressbar feedback ? My data is coming from an access mdb.
View 4 RepliesI'm working on VB .NET 2008.
Target: Bind dynamic datasource in a cell of a Windows.Forms.DataGridView depending on the selection in previous column. The grid must have 7 columns. If the selection on comboboxcolumn 2 or 4 is done, the datasource of comboboxcolumns 3 and 5 mus change using a query with previous selection as parameter.
In a first try to develop this functionality i've tried to use Telerik.WinControls.UI.RadGridView control. I've created a customized celltemplate with a combobox in order to have different datasource for each cell on the same column. All worked fine but seems to be some kind of bug in RadGridView, because when the combobox is presenting the list, after selection the list continued showing, doesn't dissapears as expected.
Ok, after several days of fight with RadGridView, I give up, and I tried to use same strategy but using Windows.Forms.DataGridView. I've created two classes one inherited from DataGridViewComboboxCell and other from ComboBoxColumn, in order to insert my own combbox or have the chance to have access directly to the combobox values. But the combobox showed is the default combobox not my own combobox.
how can I create a custom comboboxcell but using my own combo, and having access from outside to this combo?
public Enum ClaimStatus
Ongoing = 0
Completed = 1
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With code above, how do I assign the value to the combobox while retrieving data from the table so that it point to the corresponding combobox item. For example, if the value of status_ID is 1 then the combobox should show "completed" in the datagridview.
I have a datagridview with a datatable in a dataset as a datasource. When i add a new row in the datagridview it is automaticaly added to the to the underliyng datatable (its datasource) . However it will only be addad after i click another datagridviewrow. I would like that update to be just after i added the row or after i edit one of its cells and not only after i click a different row.
View 8 RepliesPosted this over at WinForms forum, just not much activity and thought I might get a quick response here....Not real certain if I am implementing this correctly, but I am attempting to programatically modify cell values in a DataGridView control with an underlying DataTable as it's DataSource.
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I have a datagridview with 3 columns.
Now I need to fill the datagridview's datasource with 3 arrays.
Example:
(column1) Username- Joe - Mark - Thomas
(column2) Password - Joe - Mark - Thomas
(column3) Activiated - Yes - No - Yes
Then after i split what should I do? Should I add 3 arraylists in a class or should I use structure and how?
To add Row programmatically,
Connected Datagridview with datatable
I like to add Blank Row in the datagridview, So
On the Last Cell, CellLeave Event
Datatable1.Rows.Add()
It is adding a row in the dataTable, but adding two rows in the datagridview, why...?
I'm trying to use a datagridview as the datasource for my mail merge, but I'm having trouble getting all the data to output to the word doc. I've based the below code on the following tutorial:
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This is my first time really working with DataGridViews. And for my own learning, I am trying to create a "System Information" program. I understand you can easily do simple stuff such as:
DataGridView1.Rows.Item(0).Cells(0).Value = "OS Name"
DataGridView1.Rows.Item(0).Cells(1).Value = My.Computer.Info.OSFullName
