value change in datagrid

[Guest]

Hello,
How can I trigger an event, when a value (cell) in my datagrid changes?
TIA,
amber

 

[W.G. Ryan eMVP]

There's a CurrentCellChanged event which should do it for you.

 

[Todd Harvey via DotNetMonster.com]

hey - that event is when you change cells in the grid, not for when you change the contents of a cell ... I'll post back when I get what she wants, I want the same thing just now.

 

[W.G. Ryan eMVP]

Yes Todd you're right. And that's one very easy way to check if something
has changed or not. There are a few ways to go about getting the
values -but remember that when you start changing something, the changes
aren't finsihed until the current edit is ended. That's why if you're
typing something in a cell who's column is sorted, it doesn't start sorting
as you type - it's only when you are done editing that the value will get
sorted -so is it here.

--
W.G. Ryan, MVP

www.tibasolutions.com | www.devbuzz.com | www.knowdotnet.com

hey - that event is when you change cells in the grid, not for when you

change the contents of a cell ... I'll post back when I get what she wants,
I want the same thing just now.

 

[W.G. Ryan eMVP]

Amber - after reading Todd's post I realized that my post may have been
confusing. YOu can use CurrentCellChanged to determine when you have moved
to another cell. Based on the way editing in a grid works - the edit
doesn't take until endcurrentedit. Depending on what you ultimately want to
do -there are a few different approaches. RowChanging on the underlying
datatable is another way to make that determination

 

[Guest]

Thanks,
What I'm actually trying to do is set a variable ('isDirty') to true, if the
value in any cell in my datagrid changes.
Maybe I'm going about this in the wrong way?
Amber

 

[W.G. Ryan eMVP]

An easy way to do this is to check the underlying DataSet's HasChanges
property - this way regardless of how the data gets changed, you can
recognize it.

 

[Todd Harvey via DotNetMonster.com]

you guys are super active on this board! you've got like 5 responses since yesterday afternoon on this

I actually got to work what Amber's original request was - I got the OnChange to fire for the underlying text box control that is in the control array of the datagrid. And if that's not confusing, it probably should be.

When I changed a text box - or when I typed anything into my text box, it fired my little OnChange for every single character typed in, which IMHO became an almost useless event handler, and I started to re-consider W.G.Ryan's original response (and to regret my response, and to hope that he didn't start a flame war on me). The OnCellChanged is probably the best place to handle a change to the data.

Here's a brief snippet from MSDN:
Private Sub DataGrid1_CurrentCellChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGrid1.CurrentCellChanged
Dim myString As String = "CurrentCellChanged event raised, cell focus is at "
' Get the co-ordinates of the focussed cell.
Dim myPoint As String = DataGrid1.CurrentCell.ColumnNumber.ToString() + "," + DataGrid1.CurrentCell.RowNumber.ToString()
' Create the alert message.
myString = myString + "(" + myPoint + ")"
' Show Co-ordinates when CurrentCellChanged event is raised.
MessageBox.Show(myString, "Current cell co-ordinates")

End Sub

---------------
Here's the ugly thing to associate an event with the underlying control:
' how to add the event listener for all the text boxes?
For i As Integer = 0 To Me.dgEquipment.Controls.Count - 1
Dim ctl As System.Windows.Forms.Control = Me.dgEquipment.Controls.Item(i)
System.Console.Write(ctl.GetType().Name)
System.Console.Write(" ")
System.Console.Write(ctl.Text)
System.Console.WriteLine("")
If (ctl.GetType().Name = "DataGridTextBox") Then
AddHandler ctl.TextChanged, AddressOf txtQuantity_NullTextChanged
'OnTextChanged
End If
Next


Private Sub txtQuantity_NullTextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtQuantity.NullTextChanged
System.Windows.Forms.MessageBox.Show(" changed ")
End Sub

I gave up on this approach in favor of W.G.Ryan's ... but you could associate any event you wanted, I suppose. And you could associate it only with certain columns, if you wanted.

This thread is turning out to be fruitful for me (I didn't know about the IsDirty thing , getting to the underlying controls was handy, and in the course of this I found some really cool stuff about putting all kinds of user controls in the data grid: http://www.codeproject.com/cs/miscctrl/WindowsDataGridColumns.asp#xx983919xx (and their associated events)

But it is funny that while I did what Amber said she wanted, I didn't like it.
W.G.Ryan answered what she didn't ask, and I'm using it.
Amber actually meant something other than what she said, W.G. took care of that too, and it helped everybody.
And maybe more.

 

[Todd Harvey via DotNetMonster.com]

I have spent way too much time on this, but I have a grid with
Unit Price, Quantity, Cost, and I want it to automatically update
cost = price * quantity
as the user enters quantity.

I have it working.

It is extremely ugly (I capture events for grid controls, I grab the text box I'm entering into, and anyway, it works.)
Perhaps if it were not a bound grid, it would be easier. Message me if you are interested. todd_harvey@[email protected]