I know I need to provide some code, but I'm not sure what I should show, so please suggest if you can.
I have a bound datagridview on a Windows form. After the form loads and the datagridview gains focus (on mouse click), the first row (and a specific column) loses it's data, changing the cell's state to dirty. It doesn't matter where I click to bring the dgv into focus, that row/column always goes blank. What event is firing that may trigger that loss of data?
Again, any suggestions as to what code to post would be great. I know that will help answer this question.
Edit #1
This code is an infinite loop, but I'm adding it in response to a comment:
Private Sub dgQCOrders_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles dgQCOrders.CellPainting
If e.RowIndex = 0 And e.ColumnIndex = 9 Then
If e.FormattedValue <> e.Value Then
MsgBox("Changed")
Else
MsgBox("Unchanged")
End If
End If
End Sub
Edit #2:
Private Sub dgQCOrders_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles dgQCOrders.CellPainting
If e.RowIndex = 0 And e.ColumnIndex = 9 Then
If e.FormattedValue <> e.Value Then
Me.txtTest.Text = "Changed"
Else
Me.txtTest.Text = "Unchanged"
End If
End If
End Sub
This test tells me that the new value is null, it is deleting that first record (which I already knew)--still don't know how to fix it!
Edit #3
More explanation:
Currently, the only event I'm handling is form_Load, which fills the dgv using the tableadapter for my (bound) dataset. I then bind the dgv to the binding source.
I know that this error only occurs when the dgv gains focus (I tested this by setting the focus to the dgv when the form loads). I have a series of checkboxes/listboxes/textboxes on this form as well that allows the user to filter the dgv dynamically (back-end, I filter the binding source). If I filter the dgv first, the same row and the same column (their indexes do not change) maintains it's value when I move the focus to the dgv. When I clear the filter, the same row and the same column, loses it's data again.
I did have the _CellStateChanged event firing after a user makes an edit. Currently, it is commented out so the data loss isn't reflected in my dataset.
Additionally, I have another dgv on a different form, bound the exact same way, with the _CellStateChanged event and everything fires and saves correctly. I have gone through the designer coding for both forms, I can't find any setting difference between the two.
I'm losing my mind over here! Any help is GREATLY appreciated!
I decided to recreate the form from scratch and this error is no longer occuring. I have compared the two sets of code and can't find one discrepancy between them. If anyone has this problem in the future, save time and recreate all of the objects related to your dgv.
Maybe I understand that statement within the focus cell is not saved in the database table if U save
this problem I solved
add blank textbox control to your form which contain dgv and named txtFocus
placed it behand dgv and use its properties send to back Or
Evoked by the bottom of the screen so do not show it
then
before save
white then :
txtFocus.Focus()
sendKeys.send("{F2}")
only in this case U can save the data inside last cell changed in dgv
best Reg
Ashraf
Related
I'm trying to add a column to an existing data grid view and I'm getting an error after adding a column. Referencing the column by it's name throws a null reference exception and after some debugging I noticed, the names of the columns have disappeared after adding a column.
Before I add a new column you can see in the first image, that each column has a name. After I add a column, the second image shows the names of each column as being empty. No code was changed and the column being added to the data grid view was the only change.
DGV_List.Columns("Vendor").Visible = CB_Vendor.Checked
I've found one or two ways to get around this, such as directly referencing the column like Me.Vendor.Visible. But I'm curious why adding a new column could cause existing working code to fail.
Edit adding code
The code is really long so I'm linking it on pastebin. Also note the column was added manually and not with code. Nothing besides the form designer code changed when the error started.
Code that has null reference error after adding column
https://pastebin.com/inZCT27A
Form designer before adding column
https://pastebin.com/2nv33pA3
Form design after adding column
https://pastebin.com/7ULHpNwE
I am pretty sure that the problem lies in “WHEN” the CheckBoxs CheckedChanged event is fired.
If the check box is set to True in the designer, then, its CheckedChanged event will get fired "once" in the InitializeComponent method.
If the check box is set to False in the designer, then its CheckedChanged event will NOT be fired in the InitializeComponent method.
Because the check box is set to true in the designer, then "sometime" in the InitializeComponent method the CheckChanged event is going to get fired and when it does... you can NOT guarantee that the grid has been fully initialized.
Checking “anything” relating to the grid “before” it has been fully initialized is risky. This would easily explain some of the inconsistencies I and I am sure you have seen.
The main point would be that, because you DO want to reference the grid in the CheckChanged event of the check boxes, AND you DO want to have the check box initially checked, then you need to make sure the grid is fully initialized "before" you set the check box to True/False (checked/unchecked).
One way to do this is from the “designer”, UNCHECK the check boxes that reference the grid. This will prevent the CheckedChanged event from firing in the InitializeComponent method when the grid may not be fully initialized.
Then in the forms Load event, where we can pretty much guarantee the grid is initialized fully, set the check boxes state to checked. Then the CheckedChanged event can fire without errors. …
Private Sub MCRI_Checker_Form_Load(sender As Object, e As EventArgs) Handles MyBase.Load
CB_Description.Checked = True
CB_Drawing.Checked = True
CB_FilePath.Checked = True
CB_Quantity.Checked = True
CB_ReqType.Checked = True
CB_Vendor.Checked = True
CB_WhereUsed.Checked = True
End Sub
I hope this helps and makes sense.
I have a DataGridView control on a TabPage of a Windows Form application.
When the user moves the mouse over the DataGrid and uses the scroll wheel, the grid scrolls as expected. But when the user clicks in a cell on the screen, instead of the cell receiving focus, the DataGrid resets to the top and requires the user to scroll down again. This response is non-intuitive since it's not immediately obvious that the cell you thought you clicked on isn't there anymore.
I would be happy to prevent the DataGrid from responding to the scroll wheel until the user clicks in the grid, or preferably to maintain the current actions except not resetting to the top when first clicked.
From what I've researched here, it appears that the DataGrid is rebinding because I'm resetting the binding when the tabpage is entered (since the database might have been updated by one of the other tabs.
Private Sub TabPage1_Enter(sender As Object, e As EventArgs) Handles TabPage1.Enter
LoadTACTable()
End Sub
In LoadTACTable():
dbGetList("spSelectTACList", dtTACs, 0, 100000, Nothing) ' Record numbers are 0 based
bsTACs.DataSource = dtTACs
With gridTACs
' TOTAL Grid width = 1380
.DataSource() = bsTACs
.
.
.
(Showing only part of the code for brevity.
Is there a way to see if the TabPage is already displayed when entered? Or, is unnecessary to reset the gridTAC datasource every time I retrieve the data from the SQL database to the dtTACs datatable using my dbGetList() sub?
There are several possible solutions to your problem. One would be to not automatically rebind the datagrid but let the user do it by clicking some refresh button. That way the user would not see non-intuitive behavior.
You mentioned that the contents of one tab may need to be refreshed when the contents of other tabs are changed. Whenever the contents of a tab is changed and can affect other tabs, you could flag these other tabs (for example, by adding a star to their titles) to indicate that they no longer have the latest data. The user would then know that the tab needs to be refreshed.
There might be other solutions, but it is difficult to tell without knowing more about your use case.
With the guidance above, I believe I solved the issue:
I created a flag:
Dim TabDirty As Boolean
Then I set it in the TabPage.Leave handler:
Private Sub TabPage1_Leave(sender As Object, e As EventArgs) Handles TabPage1.Leave
dtTACs.Dispose()
TabDirty = True
End Sub
Then I just check it when I enter the TabPage:
Private Sub TabPage1_Enter(sender As Object, e As EventArgs) Handles TabPage1.Enter
If TabDirty = True Then
TabDirty = False
LoadTACTable()
End If
End Sub
So far, this appears to work - the grid is not getting reset when clicked, but I will do a bit more testing to confirm that the data is refreshed when necessary.
First of all I would like to thank all of you guys. Maybe you did not notice but you help me to grasp VBA to some level from scratch. I am still in learning process so I may be missing something really simple, please be gentle :)
First of all I would like to give a small backgroud update about my issue. I have been writing a small program to scan incoming parts to my work to be able to keep inventory status. Latest look of the program is like below:
And numbers on the picture are my nightmares lately:
1. Scanned Part Number: This is the textbox where scanner inputs the value. After I receive the input I immidietly convert that data to a variable and clear the textbox value as below:
Private Sub PN_CurrentScan_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
If KeyCode = 13 Then
EnteredPN = Replace(PN_CurrentScan.Value, Chr(32), "", 1) '<---PN_CurrentScan is the name of text box
EnteredPN = Left(EnteredPN, 12)
PN_CurrentScan.Value = ""
After making some corrections on the scanned data I basically write it to a sheet in the workbook. Then I also have a pivot table in the same workbook which uses this scanned data as source and counts how many parts scanned from each part number.
2. Current Status: This ListBox contains all the part numbers scanned (Coming from the pivot table mentioned above) and waiting to be scanned (Coming from another worksheet). Then it refreshes it self every time a new part is scanned.
3. ListBox Scroll Bar: Since I have very long part number list it is not possible for me to fit everything on the screen that is why listbox creates this scroll bar.
Enough with the background I think :)
So if we come to my concern. Since my collages using cordless scanner to do this operation sometimes they don't have the chance to see the screen so they can not understand if the cursor is on the "Scanned Part Number Text Box" or not. That is why I need focus to be on that box no matter what happens (Of course we can not do anything if warehouse burns down, earth quake or tsunami hits the place but let do not think about those).
WHAT I HAVE TRIED:
First of all I disabled all the remaining objects from properties window
Then I diabled tab stops of all controls:
Dim contr As Control
For Each contr In ScannerInterface.Controls
On Error Resume Next
contr.TabStop = False
Next
ScannerInterface.PN_CurrentScan.TabStop = True
Added setfocus property to all button clicks:
Me.PN_CurrentScan.SetFocus
Added setfocus property to listbox click:
Private Sub CurrentStatus_List_Click()
Me.PN_CurrentScan.SetFocus
End Sub
Added set focus to enter and exit events of listbox however this did not work:
Private Sub CurrentStatus_List_Enter()
Me.PN_CurrentScan.SetFocus
End Sub
Private Sub CurrentStatus_List_Exit(ByVal Cancel As MSForms.ReturnBoolean)
Me.PN_CurrentScan.SetFocus
End Sub
So, with all these counter measures I have managed to improve up to somepoint, only concern remaining is when I click on the scroll bar next to the listbox, text box lose focus and without clicking in the textbox I could not manage to set the focus again. I tried all events with listbox non of them worked. Is there any way to solve this problem or do I need to deal with this? Thanks in advance for your supports.
SOLUTION:
Thanks to #Rory we have managed to solve my problem. As he noticed and explained in the answer below, both my textbox and listbox were in frames. I have tried several setfocus options but I always gave the focus to the textbox. However, solution was to give the focus to the frame which was containing the target textbox:
Private Sub CurrentStatus_Frame_Enter() '<-- Enter event of the frame which contains listbox
Me.PN_CurrentScan.SetFocus '<-- Setfocus to target textbox
Me.Scanned_Frame.SetFocus '<-- Setfocus to frame which contains target textbox
End Sub
Having (eventually) noticed that both of your controls are inside container Frame controls, you can actually use the Enter event of the Frame that contains the listbox to set focus to the Frame that contains the textbox, rather than to the textbox itself.
I have some controls bound to a BindingSource control.
I want to do a calculation when the value changes in one control and set the result on another control.
Do I update the textbox the property is bound to or do I update the underlying entity which would update the control anyway (I hope)?
When I change combobox A (OnPropertyChange) textbox B is updated with the new calculated result. This works fine, but I have noticed that when I leave combobox A it reverts back to its original value. What is going on here!
Private Sub ComboBoxEditCostCode_EditValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBoxEditCostCode.EditValueChanged
Select Case ComboBoxEditCostCode.EditValue
Case "7"
CType(TransactionEntityBindingSource.Current, TblTransactionsEntity).Qbdescription = "7-is here"
Case "2"
CType(TransactionEntityBindingSource.Current, TblTransactionsEntity).Qbdescription = "2-is here"
Case Else
CType(TransactionEntityBindingSource.Current, TblTransactionsEntity).Qbdescription = "7-is here"
End Select
End Sub
if we bind a control to a source, then if the source changes, we can make the its value automatically reflected in the control. About the problem you are facing, it would be better if you show the code snippet.
Tell more about your changing, how second text box is bound?
You have to change your initial data instead of changing textbox b value.
Also when textbox A loses it focus raises EndEdit event and I think binding mechanism refreshes value in textbox B.
You can control on which action editing is done when you setting your binding to textboxes.
as a rule of thumb, if you are using a binding source you always CRUD the data through it. Don't forget to call BindingSource.EndEdit when you are done, hope this helps
I have a DataGridView to which I've set a list of objects to the DataSource. (I'm in VS 2005 using VB.) I created the DataGridView by creating a Data Source of type AssetIdentifier and dragging that Data Source onto my form.
I want to update the DataGridView when the selection in either a combo box or another DataGridView changes. (Below I'm considering a click in another DataGridView.) The following works:
Public Class dlgShowAssets
' class member variable
Private assetIdList As List(Of AssetIdentifier)
' pertinent subs and functions
Private Sub RefreshAssetIdentifierDataGridView()
AssetIdentifierDataGridView.DataSource = assetIdList
End Sub
Private Sub AssetDataGridView_CellClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles AssetDataGridView.CellClick
assetIdList = RepopulateTheList(id)
Me.RefreshAssetIdentifierDataGridView()
End Sub
End Class
In this case, I always knew that assetIdList would have at least one element. I'd update the list, and reset the data source of the DataGridView to that list, and all was well.
When I applied this to another situation, for which I couldn't guarantee that the list would have at least one element, things would work fine as long as I had at least one element in the list, but if the list became empty, the DataGridView threw System.IndexOutOfRangeException a number of times. The rows in the DataGridView would not go away if I went from a non-zero number of elements to zero.
I tried a workaround, which was to remove all of the elements, add one "dummy" element, and then re-bind the list to the control, and it still didn't work.
Also, following all of those exceptions, I'd get other similar exceptions when I hovered over the cells in the DataGridView.
I've been trying to track down this behavior for a few hours. Any insights? Thanks!
Will be happy to add more info if needed.
UPDATE: Some of the members of AssetIdentifier were "Nothing" but I fixed that in the constructor, and the exceptions still occur.
Refactored code and it works ...