Selecting New Row in Gridview with an ObjectDataSource

[Jay Pondy]

I have a Gridview with Paging and Sorting turned on that is bound to an
ObjectDataSource which in turn is bound to a StronglyTyped datatable.

After I add a new row to my Stronglye Typed datatable and call
GridView.DataBind how can I select the row in the GridView? (And I don't mean
set the Grid.PageIndex and Grid.SelectedIndex but rather how can I determine
where in the SORTED result set the new row is.)

In the DataSourceObject Selected event I can cast the ReturnValue to my
strongly typed datatable BUT it is not yet sorted. Tracing the code shows
that the GridViews Sorting and Sorted Events have already fired so I am a bit
confused as to what is happening when. Somehow I need to set the GridViews
PageIndex and SelectedIndex based on where the new row is in the SORTED
result set.

Seems like I'm close but after two days I'm feeling a bit frustrated and
wondering again if this data binding stuff is worth the trouble. It sure
seems like ASP 2.0 is very close to making it worth the trouble so onward I
shall press.

 

[Steven Cheng[MSFT]]

Hi Jay,

From your description, you have a GridView that bound to
ObjectDataSource(which use typed dataset/datatable to supply datarows).
However, since you've turned on paging and sorting on the GridView, you
found it difficult to get the Index of a certain datarow in the GridView
and make it be selected, correct?

As for this issue, I have performed some test on my side. And here are what
I found so far:

** For GridView, when enable paging and sorting, the paged and sorted data
resultset are generated internally, that's why we can not get the paged &
sorted result set in the ObjectDataSource control's event. Also, GridView
doesn't expose interface for us to intercept this result set.

** For the selected Row, we need to set the GridView.SelectedIndex before
databinding is performed, we can not set this during databinding or when
row is creating or binding....

Currently, what I can get is the following approachs to make a certain
datarecord you want be selected in Gridview:

1)Use the GridView.RowDataBound event to get the expected row's RowIndex
(save it in a certain variable for later use) e.g.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs
e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Response.Write("<br/>" + e.Row.RowIndex);

DataRowView drv = e.Row.DataItem as DataRowView;

if (drv["name"].ToString() == "name1")
{
//save the RowIndex here
}
}

}

2) Then, after GridView has finished the first databinding, you can set the
RowIndex(saved previously) to GridView.SelectedIndex and call Databind to
redo the databinding. This drawback is that you'll need to redo the
databinding.

How do you think? If you have any further questions, please feel free to
post here.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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[Jay Pondy]

Appreciate your time and effort on this rather perplexing problem.

The problem with using the GridView1_RowDataBound event is that it only
fires for the rows that the grid will currently be displaying rather than for
all of the rows in the result set. If it fired for all the rows your
solution would work.

As an example if my grid is sorted and I am on page 1 and I add a record
that should appear on page 2 I will never see the new record in the
RowDataBound event because it belongs on page 2. Since I never see it I can
not determine it's RowIndex.

Hi Jay,

From your description, you have a GridView that bound to
ObjectDataSource(which use typed dataset/datatable to supply datarows).
However, since you've turned on paging and sorting on the GridView, you
found it difficult to get the Index of a certain datarow in the GridView
and make it be selected, correct?

As for this issue, I have performed some test on my side. And here are what
I found so far:

** For GridView, when enable paging and sorting, the paged and sorted data
resultset are generated internally, that's why we can not get the paged &
sorted result set in the ObjectDataSource control's event. Also, GridView
doesn't expose interface for us to intercept this result set.

** For the selected Row, we need to set the GridView.SelectedIndex before
databinding is performed, we can not set this during databinding or when
row is creating or binding....

Currently, what I can get is the following approachs to make a certain
datarecord you want be selected in Gridview:

1)Use the GridView.RowDataBound event to get the expected row's RowIndex
(save it in a certain variable for later use) e.g.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs
e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Response.Write("<br/>" + e.Row.RowIndex);

DataRowView drv = e.Row.DataItem as DataRowView;

if (drv["name"].ToString() == "name1")
{
//save the RowIndex here
}
}

}

2) Then, after GridView has finished the first databinding, you can set the
RowIndex(saved previously) to GridView.SelectedIndex and call Databind to
redo the databinding. This drawback is that you'll need to redo the
databinding.

How do you think? If you have any further questions, please feel free to
post here.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



==================================================

Get notification to my posts through email? Please refer to
http://msdn.microsoft.com/subscriptions/managednewsgroups/default.aspx#notif
ications.



Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscriptions/support/default.aspx.

==================================================



This posting is provided "AS IS" with no warranties, and confers no rights.

 

[Steven Cheng[MSFT]]

Thanks for your reply Jay,

Yes, you're right. When using paging , only the displayed page's item will
go through the created/bound event sequence. Another approach I can get is
manually calcualte the index(include paging context) based on GridView's
current SortExpression and SortDirection. You can get GridView's updated
"SortExpression" and "SortDirection" in ObjectDataSource.Selected event.
e.g.

protected void ObjectDataSource1_Selected(object sender,
ObjectDataSourceStatusEventArgs e)
{
Response.Write("<br/>ObjectDataSource1_Selected");

Response.Write("<br/>" + GridView1.SortExpression);
Response.Write("<br/>" + GridView1.SortDirection);
}

Then, you can try manually creating a DataView with sort setting conform to
the GridView's "sortExpression" and "SortDirection". After that you can
loop the DataRowView in the DataView to locate the index of the row you
want. This index should identitcal to the index after GridView have bound
to the Sorted the result set. For example:

==================
protected void ObjectDataSource1_Selected(object sender,
ObjectDataSourceStatusEventArgs e)
{
Response.Write("<br/>ObjectDataSource1_Selected");
Response.Write("<br/>" + GridView1.SortExpression);
Response.Write("<br/>" + GridView1.SortDirection);

_tb = e.ReturnValue as DataTable;

if (_tb != null && GridView1.SortExpression != string.Empty)
{

DataView dv = new DataView(_tb);
dv.Sort = GridView1.SortExpression + " ASC";

// check the index of the expected row in the dataview

}
}
======================

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead


This posting is provided "AS IS" with no warranties, and confers no rights.

 

[Jay Pondy]

Steven

That will certainly work and pretty much takes me back to where I left off.
It just that it doesn't seem right to have the tools (objectDataSource /
GridView) do the job and then have to do it again manually to get what you
want done.

What gripes me the most is the "you don't have to write any code or very
little code" which to some extent is true - some of these tools can save you
a lot of code BUT more often then not it seems I find myself trying to beat
the tools into submission to do things the way I want them done.

You would think that after all the million man hours MS has put into
databinding since the VBx days that somebody would recognize that users
really do like to see what they've just done. More than any other post
concering the GridView is the classic "how do I select the row".

Thanks for your help and all the great tips you have contributed to these
Newsgroups over the years. I genuinely appreciate them.

 

[Steven Cheng[MSFT]]

Thanks for your reply Jay,

Yes, in ASP.NET 2.0, many new encapsulated controls such as Gridview,
DetailsView, SqlDataSource has made the databinding codeless (just
drag/drop and configure), however the more encapsulated, the less
flexibility we will have. That's make us a bit hard to do many
customization upon those encapsulated controls. Actually, for those cases
we need more flexibility and customization, the ASP.NET 1.1 like
databinding model(through code) is the preferred one.

For this issue here, maybe programmatic databinding would be better.
Anyway, I think it a good idea that the GridView (and any other well
encapsulated controls) also provide more customization interfaces, and
you're welcome to submit such feature requests to our product feedback
center:

http://connect.microsoft.com/feedback/default.aspx?SiteID=210

As always, whenever you meet any problems that need help, please feel free
to post here.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead


This posting is provided "AS IS" with no warranties, and confers no rights.