Adding a LinkButton to a gridview, dynamically.

[jack]

Hi,
Consider the following handler:

protected void gridView_RowDat aBound(object sender,
GridViewRowEven tArgs e)
{
GridViewRow row = e.Row;
if (row.RowType != DataControlRowT ype.DataRow)
return;

Label lblRowNr = (Label)row.Find Control("lblRow Nr");
lblRowNr.Text = String.Format(" {0}.", row.RowIndex + 1);

LinkButton lnk = new LinkButton();
lnk.ID = "lnk" + row.RowIndex;
lnk.Text = "Ooops!";
lnk.Click += new EventHandler(ln k_Click); //This handler
(lnk_Click) is never get called!
row.Cells[0].Controls.Add(l nk);

}

I really don't get why the lnk_Click function is never get called.

Would you please let me know how am I supposed to do this?

Thanks
Jack

[Teemu Keiski]

Re: Adding a LinkButton to a gridview, dynamically.

Hi,

the controls should be added in RowCreated because RowDataBound fires only
when DataBind() is called, and it could be a postback when no databinding
happens, when button is clicked...essen tially on postback, it might not
exist at that point... and for a control to raise the event, it must exist
in Controls collection at the proper time

Basic idea is described in following post on ASP.NET Forums:

http://forums.asp.net/p/745417/745492.aspx

--
Teemu Keiski
AspInsider, ASP.NET MVP

http://blogs.aspadvice.com/joteke

http://teemukeiski.net

"jack" <ata@mailinator .comwrote in message
news:600b7546-3afb-46b0-9e51-38cde8b90611@t5 4g2000hsg.googl egroups.com...

Hi,
Consider the following handler:
>
protected void gridView_RowDat aBound(object sender,
GridViewRowEven tArgs e)
{
GridViewRow row = e.Row;
if (row.RowType != DataControlRowT ype.DataRow)
return;
>
Label lblRowNr = (Label)row.Find Control("lblRow Nr");
lblRowNr.Text = String.Format(" {0}.", row.RowIndex + 1);
>
LinkButton lnk = new LinkButton();
lnk.ID = "lnk" + row.RowIndex;
lnk.Text = "Ooops!";
lnk.Click += new EventHandler(ln k_Click); //This handler
(lnk_Click) is never get called!
row.Cells[0].Controls.Add(l nk);
>
}
>
I really don't get why the lnk_Click function is never get called.
>
Would you please let me know how am I supposed to do this?
>
Thanks
Jack

[Eliyahu Goldin]

Re: Adding a LinkButton to a gridview, dynamically.

You are creating the link dynamically. If you want to use dynamically
created object in postbacks, you need to re-create them on every postback in
Page_PreInint or _Init event.

I would recommend including the link into ItemTemplate and hiding it as
necessary. Then you can setup the event handler in the markup. No need to
create the link dynamically.


--
Eliyahu Goldin,
Software Developer
Microsoft MVP [ASP.NET]

http://msmvps.com/blogs/egoldin

http://usableasp.net

"jack" <ata@mailinator .comwrote in message
news:600b7546-3afb-46b0-9e51-38cde8b90611@t5 4g2000hsg.googl egroups.com...

Hi,
Consider the following handler:
>
protected void gridView_RowDat aBound(object sender,
GridViewRowEven tArgs e)
{
GridViewRow row = e.Row;
if (row.RowType != DataControlRowT ype.DataRow)
return;
>
Label lblRowNr = (Label)row.Find Control("lblRow Nr");
lblRowNr.Text = String.Format(" {0}.", row.RowIndex + 1);
>
LinkButton lnk = new LinkButton();
lnk.ID = "lnk" + row.RowIndex;
lnk.Text = "Ooops!";
lnk.Click += new EventHandler(ln k_Click); //This handler
(lnk_Click) is never get called!
row.Cells[0].Controls.Add(l nk);
>
}
>
I really don't get why the lnk_Click function is never get called.
>
Would you please let me know how am I supposed to do this?
>
Thanks
Jack

[jack]

Re: Adding a LinkButton to a gridview, dynamically.

On Jul 14, 6:21 pm, "Teemu Keiski" <jot...@aspalli ance.comwrote:

Hi,
>
the controls should be added in RowCreated because RowDataBound fires only
when DataBind() is called, and it could be a postback when no databinding
happens, when button is clicked...essen tially on postback, it might not
exist at that point... and for a control to raise the event, it must exist
in Controls collection at the proper time
>
Basic idea is described in following post on ASP.NET Forums:http://forums.asp.net/p/745417/745492.aspx
>
--
Teemu Keiski
AspInsider, ASP.NET MVPhttp://blogs.aspadvice .com/jotekehttp://teemukeiski.net
>
"jack" <a...@mailinato r.comwrote in message
>
news:600b7546-3afb-46b0-9e51-38cde8b90611@t5 4g2000hsg.googl egroups.com...
>

Hi,
Consider the following handler:

>

protected void gridView_RowDat aBound(object sender,
GridViewRowEven tArgs e)
{
GridViewRow row = e.Row;
if (row.RowType != DataControlRowT ype.DataRow)
return;

>

Label lblRowNr = (Label)row.Find Control("lblRow Nr");
lblRowNr.Text = String.Format(" {0}.", row.RowIndex + 1);

>

LinkButton lnk = new LinkButton();
lnk.ID = "lnk" + row.RowIndex;
lnk.Text = "Ooops!";
lnk.Click += new EventHandler(ln k_Click); //This handler
(lnk_Click) is never get called!
row.Cells[0].Controls.Add(l nk);

>

}

>

I really don't get why the lnk_Click function is never get called.

>

Would you please let me know how am I supposed to do this?

>

Thanks
Jack

Well, thank you. I now understand how the gridview control works.
Based on those articles I've already read, I've got two options:

1. In the occurrence of RowDataBound event, I need to save what I need
to create dynamically, in a ViewState. Then, in the RowCreated, I need
to recreate the controls based on the saved ViewStates.

2. On the Load event, I'll call the gridView.DataBi nd method, on
PostBack conditions.

The ViewState thing is really hard to do (in my scenario), since the
controls I'm creating are a lot.

Is there any better way to do this? Please note that I need the
DataItem to create my controls dynamically.

[Teemu Keiski]

Re: Adding a LinkButton to a gridview, dynamically.

Hi,

using a template e.g implementing ITemplate or custom field/column might
offer a bit cleaner route.

--
Teemu Keiski
AspInsider, ASP.NET MVP

http://blogs.aspadvice.com/joteke

http://teemukeiski.net

"jack" <ata@mailinator .comwrote in message
news:5da2b84f-294b-4ed9-b440-02891557eb8b@x4 1g2000hsb.googl egroups.com...

On Jul 14, 6:21 pm, "Teemu Keiski" <jot...@aspalli ance.comwrote:

>Hi,
>>
>the controls should be added in RowCreated because RowDataBound fires
>only
>when DataBind() is called, and it could be a postback when no databinding
>happens, when button is clicked...essen tially on postback, it might not
>exist at that point... and for a control to raise the event, it must
>exist
>in Controls collection at the proper time
>>
>Basic idea is described in following post on ASP.NET
>Forums:http://forums.asp.net/p/745417/745492.aspx
>>
>--
>Teemu Keiski
>AspInsider, ASP.NET
>MVPhttp://blogs.aspadvice .com/jotekehttp://teemukeiski.net
>>
>"jack" <a...@mailinato r.comwrote in message
>>
>news:600b754 6-3afb-46b0-9e51-38cde8b90611@t5 4g2000hsg.googl egroups.com...
>>

Hi,
Consider the following handler:

>>

protected void gridView_RowDat aBound(object sender,
GridViewRowEven tArgs e)
{
GridViewRow row = e.Row;
if (row.RowType != DataControlRowT ype.DataRow)
return;

>>

Label lblRowNr = (Label)row.Find Control("lblRow Nr");
lblRowNr.Text = String.Format(" {0}.", row.RowIndex + 1);

>>

LinkButton lnk = new LinkButton();
lnk.ID = "lnk" + row.RowIndex;
lnk.Text = "Ooops!";
lnk.Click += new EventHandler(ln k_Click); //This handler
(lnk_Click) is never get called!
row.Cells[0].Controls.Add(l nk);

>>

}

>>

I really don't get why the lnk_Click function is never get called.

>>

Would you please let me know how am I supposed to do this?

>>

Thanks
Jack

>
Well, thank you. I now understand how the gridview control works.
Based on those articles I've already read, I've got two options:
>
1. In the occurrence of RowDataBound event, I need to save what I need
to create dynamically, in a ViewState. Then, in the RowCreated, I need
to recreate the controls based on the saved ViewStates.
>
2. On the Load event, I'll call the gridView.DataBi nd method, on
PostBack conditions.
>
The ViewState thing is really hard to do (in my scenario), since the
controls I'm creating are a lot.
>
Is there any better way to do this? Please note that I need the
DataItem to create my controls dynamically.