Question

Using the walkthrough from [[http://msdn.microsoft.com/de-de/library/15a31akc.aspx]], I implemented a DatagridView in virtual mode, totally unbound, in VB 10 Express (we are talking WinForms).

I understand that CommitEdit (DataGridViewDataErrorContexts.Commit) commits the current cell’s contents to the data cache.

The example uses row-level commit, i.e. it pushes the values into a row buffer until the current row is left. Only then the row is added to (or updated in) the data store. That’s exactly what I do, too.

Question — how can I commit the current row programmatically without leaving it? (I want to commit the whole row, not just the current cell.)

If the user leaves the row, there is a RowValidating, RowValidated, RowEnter event sequence where the datastore update is taken care of. So one idea (currently my only one) was to simply re-set CurrentCell to Nothing, for example.

But I cannot just set the DataGridView‘s CurrentCell property to Nothing (or any cell outside of the current row) since I want to commit from within an event handler of a custom edit control created by a custom column, and I see an System.InvalidOperationException exception when setting CurrentCell there.

In fact, it is a tiny button right to a combo box, i.e. I create a DataGridViewComboBoxCell descendant which is a DataGridViewComboBoxColumn descendant’s edit control. My special ComboBox cell adds a tiny button which should commit the current row. Unfortunately, that button’s _Click event handler cannot change CurrentCell since DetachEditingControl throws the exception then.

Obviously, I must delay the CurrentCell re-assignment until the whole _Click event has been processed. Or what? How would I do that — register a custom Windows message, SendMessage that one to me, and override the windows procedure of the form so it re-sets CurrentCell when this message is received? (Hello?)

There should be a rather easy way to let DataGridView commit all changes by firing the events that I handle to perform the datastore update, no?

I hope it is somewhat clear what I am talking about. I do not have a compact code example yet 🙁

Answer 1

Here is a reliable way to commit the current row:

' Optional: mark the current cell as dirty so the current row definetely will be
' commited:
MyDataGridView.NotifyCurrentCellDirty(True)

' Aktuelle Row commiten. Einen besseren Weg als "Keine Zelle selektieren, dann Originalzelle wieder selektieren" kenne ich nicht:
Dim OrigCellAddress As Point = New Point(MyDataGridView.CurrentCellAddress.X, MyDataGridView.CurrentCellAddress.Y)
MyDataGridView.CurrentCell = Nothing
MyDataGridView.CurrentCell = MyDataGridView.Rows(OrigCellAddress.Y).Cells(OrigCellAddress.X)

The problem with the exception was a BeginEdit/EndEdit sequence i perform in my RowEnter event handler 🙁 which resulted in an indirect recursive call of non-reentrant stuff.