Datagrid Issues

[Megan]

I'm currently trying to develop a solution containing a bound DataGrid
that allows insert and update functions. I'm having 2 problems that
i'd appreciate some help with.

The first problem is where I have a primary key field that I don't
want users to be able to modify. The obvious solution is to configure
the column to be read only. However, then when a user tries to insert
a record, that column is still read only and so nothing can be
entered.

The second problem i'm having is to do with validation. I have a
RowChanging event on the underlying DataTable that validates the data
and if there are any problems uses SetColumnError to flag the issue to
the user. I also have a Validating event on the DataGrid that I use to
confirm that there are no errors before a user can leave the grid. The
problem is that the RowChanging and Validating events both fire at the
same time. So that if a value is changed to an invalid value and then
the grid is left, the value has not been flagged as an error when the
Validating event runs.

I hope I have explained these issues well enough. Any help or
suggestions would be welcomed.

 

[Alok]

Megan,
Regarding the first issue..
Could you not set the primary key constraint on the dataset itself, instead
of changing the column styles.
For the second problem, i don't think you need to handle both the validating
and the row changed event. only the row changed should suffice.

 

[Megan]

Setting the primary key on the underlying DataTable does not stop the
user from being able to modify the primary key field(s) within the
DataGrid.

I want the row changed event to check the modified data for errors.
But if there are errors, I simply use the SetColumnError function to
flag these as errors (ie: it doesn't stop errors from being entered,
just lets the user know of the problem). I therefore then need the
validating event to ensure that all errors have been fixed before the
grid is left. It is only after this (ie: in the validated event) that
the changes made in the grid get written back to the database.

Hope this clears things up a little.

 

[Alok]

Could you not in the row changed event call RejectChanges() method of the dataset. It would rollback the errors.

regarding the first question could you handle the current cell changed event of the grid. Check if this row exists in the underlying table. If it does RejectChanges() else continue.

Check this article out in MSDN:
http://msdn.microsoft.com/library/d...lingerrorswithwindowsformsdatagridcontrol.asp

HTH