ObjectDataSource->Gridview Clear?

[GaryDean]

I have an objectdatasource reading a dataset and I have a gridview using
that objectdatasource (at design time).

It binds fine but I need to clear it.
myGridView.DataSource = null:
myGridView.DataBind();

does not work! There is no clear method for the ODS. How do I get rid of
it?

 

[Guest]

Howdy,

Unfortunatelly, you cannot clear gridview if datasourceid is assigned (from
logical point of view clear operation does not quite make sense). Because
myGridView.DataSource = null:
myGridView.DataBind();
is simply ignored, you are not getting 'Both DataSource and DataSourceID are
defined on "myGridView". Remove one definition.' exception. But try binding
with empty data source i.e.

myGridView.DataSource = new int[0];
myGridView.DataBind();

and you'll get it. Anyway, i see what you're trying to do. on first page
request, objectdatasource is used to populate gridview (remember it happens
in gridviews's onprerender method that raises PreRender event), and then on
postback, you want to clear the gridview:

protected void btnWhateverClick(object sender, EventArgs e)
{
myGridView.DataSourceID = String.Empty;
myGridView.DataSource = new int[0];
myGridView.DataBind();
}

and you're done.

Hope this helps

 

[Steven Cheng[MSFT]]

Hello Gary,

For those ASP.NET 2.0 DataBound controls, since it provides a new
DataSource control bound model(you can add the binding relation at
design-time or runtime), you should use the "DataSourceID" property instead
of the DataSource(which is dedicated for programmatic databinding) to
control the databound control's associated datasource.

So for your scenario, since you've choosed an objectdatasource for your
GridView at design-time, the DataSource control ID has been save in the
GridView's DataSourceID property. In sequential requests(include
postback), even if you manually change GridView.DataSource, Gridview will
still use the "DataSourceID" (the associated datasouce control) to populate
data collection. Thus, you can simply change Gridview.DataSourceID to
empty string and call databind to clear it. e.g.

===============
protected void Button1_Click(object sender, EventArgs e)
{
GridView1.DataSourceID = string.Empty;
GridView1.DataBind();
}
================

Hope this helps.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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[GaryDean]

Oh yes, now I remember.
Thanks much !

 

[Steven Cheng[MSFT]]

You're welcome.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead