Refresh databinding?

I have a form where I want to populate a grid wih a dataset table.

To get the convenient designtime help I have dragged a typed dataset onto
the form, thus receiving a dataset control and a bindingsource control on the
fly.

As the dataset is quite heavy I want to reuse an existing dataset of the
main form, already loaded with data. The dataset is sent to the subform
constructor as a reference.

Problem is that when I change datasource of the grid I loose specific
formatting, set through the designer bindingsource.

My idea then was to try switching the datasource of the bindingsource
control. This seems to partly work. The bindingsource reports to have the
correct number of records. BUT they still don't show up in the grid!

Me.TblFeedbackBindingSource.DataSource = _ds

I expected some kind of refresh mechanism, but the data is not shown until I
add this line, where I specify the datasource of the grid ONCE AGAIN. Why is
this necessary to do again?
grdFeedback.DataSource = Me.TblFeedbackBindingSource

RobinS
Thu Jan 25 15:57:41 CST 2007

What do you mean, when you change the data source of the grid? Is it
just
the one statement you've given?

One thing is if that is a dataset, you need to specify which table in
the
dataset the binding source should use, like this:

TblFeedbackBindingSource.DataSource = _ds.Tables("Customers")

If it's strongly typed, you can access the table name directly,
something
like this:

TblFeedbackBindingSource.DataSource = _ds.CustomerTable

HTH.
Robin S.
--------------------------------------------------------------------

"Jakob Lithner" <jaklithn@noemail.noemail> wrote in message
news:1137C0E7-4A74-4E2B-BF3D-26C7D7AAE597@microsoft.com...
>I have a form where I want to populate a grid wih a dataset table.
>
> To get the convenient designtime help I have dragged a typed dataset
> onto
> the form, thus receiving a dataset control and a bindingsource control
> on the
> fly.
>
> As the dataset is quite heavy I want to reuse an existing dataset of
> the
> main form, already loaded with data. The dataset is sent to the
> subform
> constructor as a reference.
>
> Problem is that when I change datasource of the grid I loose specific
> formatting, set through the designer bindingsource.
>
> My idea then was to try switching the datasource of the bindingsource
> control. This seems to partly work. The bindingsource reports to have
> the
> correct number of records. BUT they still don't show up in the grid!
>
> Me.TblFeedbackBindingSource.DataSource = _ds
>
> I expected some kind of refresh mechanism, but the data is not shown
> until I
> add this line, where I specify the datasource of the grid ONCE AGAIN.
> Why is
> this necessary to do again?
> grdFeedback.DataSource = Me.TblFeedbackBindingSource
>
>

v-lliu
Thu Jan 25 21:51:49 CST 2007

Hi Jakob,

I performed a test based on your description but could not reproduce your
problem.

When the DataSource or DataMember property of a BindingSource component is
changed, and the BindingSource component has been set as the data source of
a DataGridView, data binding will update the data in the DataGridView
automatically and we needn't set the DataSource property of the
DataGridView control once again.

Note that if you change the DataSource property of the BindingSource
component, to get the data displayed correctly in the DataGridView control,
you should ensure that the new dataset instance has a DataTable with the
same name and schema as the previous dataset instance does.

Beside the above possibility, I think other possible reasons of your
problem may be that the DataSource property of your DataGridView control
has been changed somewhere else or the the BindingSource component whose
DataSource property you changed is not the one that the DataGridView
control is bound to.

If the problem is not still solved, you may send me your sample project
that could just reproduce the problem. To get my actual email address,
remove 'online' from my displayed email address.



Sincerely,
Linda Liu
Microsoft Online Community Support

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CiaranODonnell
Fri Jan 26 06:57:01 CST 2007

If the dataset has exactly the same schema but the refresh doesnt happen
automatically, call:

TblFeedbackBindingSource.ResetBindings(false)

--
Ciaran O''Donnell
http://wannabedeveloper.spaces.live.com


"Jakob Lithner" wrote:

> I have a form where I want to populate a grid wih a dataset table.
>
> To get the convenient designtime help I have dragged a typed dataset onto
> the form, thus receiving a dataset control and a bindingsource control on the
> fly.
>
> As the dataset is quite heavy I want to reuse an existing dataset of the
> main form, already loaded with data. The dataset is sent to the subform
> constructor as a reference.
>
> Problem is that when I change datasource of the grid I loose specific
> formatting, set through the designer bindingsource.
>
> My idea then was to try switching the datasource of the bindingsource
> control. This seems to partly work. The bindingsource reports to have the
> correct number of records. BUT they still don't show up in the grid!
>
> Me.TblFeedbackBindingSource.DataSource = _ds
>
> I expected some kind of refresh mechanism, but the data is not shown until I
> add this line, where I specify the datasource of the grid ONCE AGAIN. Why is
> this necessary to do again?
> grdFeedback.DataSource = Me.TblFeedbackBindingSource
>
>

jaklithn
Mon Jan 29 09:43:02 CST 2007

My own fault!

Today I detected an event handler that had a line of code setting the grid
datasource to nothing, which of course explains all ..... !

Sorry about that.