how to delete record from persisted store when user deletes row in Datagridview - vb.net

I am currently using this:
Private Sub PersonDataGridView_UserDeletingRow(sender As Object, e As DataGridViewRowCancelEventArgs) Handles PersonDataGridView.UserDeletingRow
DBContext.Persons.Remove(e.Row.DataBoundItem)
End Sub
But this behaves strange: it sometimes deletes the right record, but then gives an error about index out of range (translated from Dutch: error in Datagridview: index out of range: ThrowArgumentOutOfRangeException) afterwards;
Example: I have 5 rows in the datagridview; I delete row 3 using the above code, then rows 3 and 4 are removed from the datagridview. This causes an error when trying to save the DBcontext on that second deleted row, because it has not been set to "deleted" in the context...

You want to use UserDeletedRow. Using the UserDeletingRow, you are deleting record 3 from the data source as you want, but then the datagridview changes and it will fire the userdeletingrow again.
You want to perform the delete in the data source only after the record has been deleted from the gridview.

Related

Refreshing another subform upon changing a value in first

In my form called HPCC I have 2 subforms: Items_form and Item_details_form. Item_details_form is linked with Items_form so whenever you select a record in Items_form coresponding record in Item_details_form is selected. I want to refresh Item_details_form whenever I change Id field in Items_form I can see changes immediately without manualy refreshing whole form.
I've tried creating an event in Items_form:
Private Sub nr_AfterUpdate()
forms!HPCC!Item_details_form.Requery
End Sub
nr is my auto incremnet primary key in both subforms.

Get the actual value of a BoundField element in a gridview VB.NET

The following image depicts the full gridview I have:
I'm able to get the values of the second column (project_ID) in the back end as follows:
Dim val As String = grdProjects.SelectedRow.Cells(1).Text.ToString
For instance if I press the Select of the third row I'll get back the value 3.
My problem appears when the gridview is updated and has less records as the one in the following image.
If I press the second record I get the value 2 instead of the value 4 that I'd like to get.
Any suggestions please on how to get the actual value of the cell instead of the number of the selected row?
I might be wrong but in VB.net datagrids SelectedRow does not exist, SelectedRows do exist.
Anyway, try this way and let me know if it work:
On the RowEnter or CellClick event use the E.RowIndex to get what you want. Do as follow:
Private Sub DataGrid1_RowEnter(sender As Object, e As DataGridViewCellEventArgs) Handles DataGrid1.RowEnter
Dim CellValue As String = DataGrid1.Rows(e.RowIndex).Cells("Project_ID").Value.ToString
End Sub
Notice that for the .cells() I use the name of the column, this is better because if in the future you add columns this code will not need to be changed. Easier code maintenance always pay! Also. Cell().Value instead Cell().Text
Nandostyle

Cannot delete datagridview rows after programmatically selecting them

Hi I have a datagridview in virtual mode.
Using this code I select multiple rows if they contain a certain string:
Try
For Each row As DataGridViewRow In DataGridView1.Rows
If row.Cells(1).Value.ToString().Contains(TextBox1.Text) Then
DataGridView1.Rows(row.Index).Selected = True
End If
Next
Catch
End Try
This code works to select the rows, but then I am unable to delete any of them using the DEL key. It's almost like the rows have not fired that they are actually selected. If I ctrl-click another row that was not part of the selection group, I can then delete all the selected rows. Does this control click fire come sort of update letting the grid know what rows are selected? How can I solve this issue?
Seems as if it was a really silly issue. I solved it by just setting focus back to the datagrid using:
DataGridView1.Focus()
I was able to reproduce the issue. I see that if you just hit the delete key after programmatically selecting the rows for the user on certain conditions the rows will not delete. I think ("not sure") because it doesn't know where you clicked the delete key. If you were to do something like the below, it would delete the selected records.
Private Sub Form1_keypressed(sender As System.Object, e As System.EventArgs) Handles MyBase.KeyDown
If Keys.E + Keys.Delete Then
For Each rows As DataGridViewRow In DataGridView1.SelectedRows
DataGridView1.Rows.Remove(rows)
Next
End If
End Sub

MS Access Can't go to specified record because of another control's VB where clause

I have a lookup listbox which is programmed to allow the user to find a specific record/help topic from the list and view it. Now when the list box is used the where clause locks in the record and the first, previous, next, last buttons freeze up and you cannot use them to go to a record. Is there a way to free up the functionality of the buttons to navigate through the records along with the where clause to select.
Here is the code that operates the listbox selections:
Private Sub List35_AfterUpdate()
Dim myTopic As String
myTopic = "Select * from FormsHelpTable where ([ID] = " & Me.List35 & ")"
Me.Form.RecordSource = myTopic
Me.Comment.Requery
End Sub
I believe since the where clause locks in the selection in the box it does not allow navigation from other controls to interfere. What might be a way around this?
You get the runtime error:
You can't go to specified record.
It appears not to be reading the other record in the source table named Help once it updates using the listbox.
Instead of changing the recordset (this is the 'pool' of records which the form could display), you just need to go to the record the user selects from the listbox.
Method 1 (probably the easiest way if your listbox is in the same order as the records of your form)
Use this code:
Private Sub lstSelect_AfterUpdate()
DoCmd.GoToRecord acDataForm, "HelpForm", acGoTo, Me.lstSelect.ListIndex + 1
End Sub
You need to ensure that:
The recordset of the form is ordered the same as the listbox. So, for example, you could order both by ID, or by Title.
Note that the +1 comes from the fact that the ListIndex starts at 0, whereas the record indexes start at 1.
Method 2
Ensure each record's Title is unique (set No Duplicates on this field).
Change your listbox to return the Title of the record, rather than it's ID.
Then use this:
Private Sub lstSelect_AfterUpdate()
Me.Title.SetFocus
DoCmd.FindRecord Me.lstSelect
Me.lstSelect.SetFocus
End Sub
Things to note:
It works by searching the field with focus for the string specified. That's why we have to SetFocus on the Title textbox on our form.
We could use ID instead, (which would mean we could have duplicate titles if we wanted), but then we would have to have an ID control on the form to SetFocus to. You can't hide this control either, because it needs to have focus whilst using FindRecord.
Update: Method 1 with reverse-selection
Add an Event Procedure in the Form_Current event, with this code. Then update the code in the lstSelect_AfterUpdate procedure as shown after.
Private Sub Form_Current()
Me.lstSelect = Me.lstSelect.Column(0, Form.CurrentRecord - 1)
End Sub
Note that, depending on how your lstSelect is set up, it may be Column(1, Form.CurrentRecord - 1) instead. Read on for details!
Private Sub lstSelect_AfterUpdate()
DoCmd.GoToRecord acDataForm, "HelpForm", acGoTo, Me.lstSelect.ListIndex + 1
Me.lstSelect = Me.lstSelect.Column(0, Form.CurrentRecord - 1)
End Sub
Explanation of new lines:
The Form_Current event fires every time we go to a new record. We need to look at the index of the record (ie. the position of it in the recordset), which we get by using Form.CurrentRecord. We then want to make the listbox select that record. However, we can't use me.lstSelect.ListIndex as before, because that is a read-only property (we can access it to read it, but we can't set it).
Therefore, we use me.lstSelect.Column(colNum,rowNum) instead, where we specify a column number and a row number. If your listbox has two columns (eg. ID and Title), we want to choose the second column. The index starts at 0, so we would use a value of 1. If, like my lstSelect, you only have one column (Title) then we use 0. Note: it doesn't matter if a column is hidden (ie. has width 0). It still 'counts'.
The row number is Form.CurrentRecord - 1. Remember that the forms recordset index starts at 1, but the index of our listbox starts at 0; hence the - 1.
So why do we need a duplicate of this new row in the AfterUpdate event? Try and comment it out to see what happens if we don't put it in. It's has to do with the Form_Current event firing after we use the listbox.
I fixed this issue with a union clause in the SQL lookup code. The UNION ALL clause and the following union on the table used in the other part had allowed all the records to be used.

figure out rowindex on a row I just inserted?

I've got a vb project I am updating and it has a datagridview, a panel, and buttons along the bottom. The buttons control CRUD operations. The panel shows numerical up/downs and textboxes to represent the selected row.
I use some logic to keep track of current selected row and current row index for timer updates in the background. Upon delete I reset focus on the first row. Upon loading I set focus on first row. On update I keep current row focus.
Upon a good insert I would like to set the focus to the row I just inserted. But I do not know a way to determine what the rowindex value is for this freshly inserted row. My datatable which the datagridview uses is sorted on two id columns so it's not like the new entry will just jump to the bottom.
Any ideas on how I can implement this?
If you don't want to deal with the RowAdded event as Jay Riggs suggested, if you add it using a row object, as opposed to just Rows.Add, you should be able to pull that off of the row object after it's inserted.
Dim dgr As New DataGridViewRow()
DataGridView1.Rows.Add(dgr)
Me.DataGridView1.Rows.IndexOf(dgr)
This should also work for insert as well.
Check out the DataGridView RowAdded event; its DataGridViewRowsAddedEventArgs parameter includes the RowIndex property which gives you what you need.
The event fires everytime a row is added, so you'll have to either wire the event up when you want to check for added rows, or ignore the event when you don't care when a row is added (such as when your grid fills with data).
If you manually add rows to the DataGridView, then you can just use the return value from the Add method. Examples:
Dim newRowIndex As Integer = myDataGridView.Rows.Add()
myDataGridView.Rows(newRowIndex).Selected = True
No need to call IndexOf. If the DataGridView is bound to a DataSource then Jay Riggs' solution of using the RowsAdded event is the way to go.