DataBinding an textbox to an Expression DataColumn

[Valentin]

I have databind a textbox to a datacolumn that happen to be an
expression.
Strangely enough, when the calculated expression value changed, it
does not seems to update the textbox. Is it bug ?

I have tried to trap the changed event on the column but because it is
an expression, I never receive the changed event.
I've trapped the row and column event on the datatable and the
dataview and force a textboxInvalid, but it does not seems to refresh
either.
Unless I manually clear the databinding and recreate, the textbox.Text
is never refreshed.
I've added a test datagrid to the the form and bind it to the
datatable containing the expression, and it is updated when using the
datagrid1.Invalid().
Any idea ?

 

[Miha Markic [MVP C#]]

Hi Valentin,

I suggest you to calculate and write the experssion yourself.

 

[Valentin]

I could calculate myself the expression, but the overall idea of using
an expression datacolumn is that it recalculates itself without any
extra coding.

I am just surprised that the same expression value displayed in a
datagrid update itself, but when bind to a textbox, it does not.

I suspect that it may be bug, but I wanted to be sure that when
binding to an expressison datacolumn to a textbox, I did not need to
indicate somewhere to refresh automatically.