Finding a PlaceHolder inside of a Repeater

[Brad Baker]

I am trying to programmaticall y set a placeholder control in csharp which is
nested inside a repeater control between <ItemTemplatean d </ItemTemplate>
tags, however I am running into problems. I've tried several different
approaches for finding the placeholder:

This:
MyControl = this.FindContro l("$form$tabs_r epeater$PlaceHo lder1");

Produces this error:
Object reference not set to an instance of an object.
This:
MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

Produces this error:
Index was out of range. Must be non-negative and less than the size of the
collection. Parameter name: index
Below is an abbreviated excerpt of my code. Can anyone suggest what I might
be doing wrong?

Thanks,
Brad
protected string GenerateNavBarL ink(string currentdepartme ntid, int SiteNum)
{
int intSiteNum = SiteNum;
string strdepartmentid = currentdepartme ntid;

LinkButton btn = new LinkButton();
btn.ID = "LinkButton 1";
btn.Command += new_department_ button_Click;
btn.Text = "Add Department +";

Control MyControl = new Control();

// Two different ways of updating the place holder
//MyControl =
this.FindContro l("form$tabs_re peater$PlaceHol der1");
//MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

MyControl.Contr ols.Add(new LiteralControl( "<li>"));
MyControl.Contr ols.Add(btn);
MyControl.Contr ols.Add(new LiteralControl( "</li></ul>"));

}

<ASP:Repeater id="tabs_repeat er" DataSourceID="r epeater_datasou rce"
runat="server">
<HeaderTemplate >
</HeaderTemplate>
<ItemTemplate >
<li><%#
GenerateNavBarL ink((Eval("depa rtment_id").ToS tring()),Contai ner.ItemIndex)
%></li>
<asp:PlaceHolde r ID="PlaceHolder 1"
runat="server"> </asp:PlaceHolder >
</ItemTemplate>
<FooterTemplate >
</FooterTemplate>
</ASP:Repeater>

[Alexey Smirnov]

On May 24, 10:30 pm, "Brad Baker" <[e-mail] spamwrote:

I am trying to programmaticall y set a placeholder control in csharp which is
nested inside a repeater control between <ItemTemplatean d </ItemTemplate>
tags, however I am running into problems. I've tried several different
approaches for finding the placeholder:

Hi Brad

I would recommend to use the OnItemDataBound event

Change the repeater

.... OnItemDataBound ="GenerateNavBa rLink">

remove from the ItemTemplate

<li><%#
GenerateNavBarL ink((Eval("depa rtment_id").ToS tring()),Contai ner.ItemIndex)
%></li>

and write new event handler

protected void GenerateNavBarL ink(object sender, RepeaterItemEve ntArgs
e)
{

.... your code here

if( e.Item.ItemType == ListItemType.It em)
MyControl =
((PlaceHolder)e .Item.FindContr ol("PlaceHolder 1")).Controls.A dd(btn);

MyControl.Contr ols.Add(new LiteralControl( "<li>"));
MyControl.Contr ols.Add(btn);
MyControl.Contr ols.Add(new LiteralControl( "</li></ul>"));

}

[=?Utf-8?B?U2VyZ2V5IFBvYmVyZXpvdnNraXk=?=]

I think that you need to consider BulletedList control - it could list
LinkButton controls as its list items

"Brad Baker" wrote:

I am trying to programmaticall y set a placeholder control in csharp which is
nested inside a repeater control between <ItemTemplatean d </ItemTemplate>
tags, however I am running into problems. I've tried several different
approaches for finding the placeholder:

This:
MyControl = this.FindContro l("$form$tabs_r epeater$PlaceHo lder1");

Produces this error:
Object reference not set to an instance of an object.
This:
MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

Produces this error:
Index was out of range. Must be non-negative and less than the size of the
collection. Parameter name: index
Below is an abbreviated excerpt of my code. Can anyone suggest what I might
be doing wrong?

Thanks,
Brad
protected string GenerateNavBarL ink(string currentdepartme ntid, int SiteNum)
{
int intSiteNum = SiteNum;
string strdepartmentid = currentdepartme ntid;

LinkButton btn = new LinkButton();
btn.ID = "LinkButton 1";
btn.Command += new_department_ button_Click;
btn.Text = "Add Department +";

Control MyControl = new Control();

// Two different ways of updating the place holder
//MyControl =
this.FindContro l("form$tabs_re peater$PlaceHol der1");
//MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

MyControl.Contr ols.Add(new LiteralControl( "<li>"));
MyControl.Contr ols.Add(btn);
MyControl.Contr ols.Add(new LiteralControl( "</li></ul>"));

}

<ASP:Repeater id="tabs_repeat er" DataSourceID="r epeater_datasou rce"
runat="server">
<HeaderTemplate >
</HeaderTemplate>
<ItemTemplate >
<li><%#
GenerateNavBarL ink((Eval("depa rtment_id").ToS tring()),Contai ner.ItemIndex)
%></li>
<asp:PlaceHolde r ID="PlaceHolder 1"
runat="server"> </asp:PlaceHolder >
</ItemTemplate>
<FooterTemplate >
</FooterTemplate>
</ASP:Repeater>

[bruce barker]

you are trying to access the placeholder before its been added to the
repeater. use the itemdatabound event instead.

-- bruce (sqlwork.com)
Brad Baker wrote:

I am trying to programmaticall y set a placeholder control in csharp which is
nested inside a repeater control between <ItemTemplatean d </ItemTemplate>
tags, however I am running into problems. I've tried several different
approaches for finding the placeholder:

This:
MyControl = this.FindContro l("$form$tabs_r epeater$PlaceHo lder1");

Produces this error:
Object reference not set to an instance of an object.
This:
MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

Produces this error:
Index was out of range. Must be non-negative and less than the size of the
collection. Parameter name: index
Below is an abbreviated excerpt of my code. Can anyone suggest what I might
be doing wrong?

Thanks,
Brad
protected string GenerateNavBarL ink(string currentdepartme ntid, int SiteNum)
{
int intSiteNum = SiteNum;
string strdepartmentid = currentdepartme ntid;

LinkButton btn = new LinkButton();
btn.ID = "LinkButton 1";
btn.Command += new_department_ button_Click;
btn.Text = "Add Department +";

Control MyControl = new Control();

// Two different ways of updating the place holder
//MyControl =
this.FindContro l("form$tabs_re peater$PlaceHol der1");
//MyControl =
(PlaceHolder)ta bs_repeater.Ite ms[intSiteNum].FindControl("P laceHolder1");

MyControl.Contr ols.Add(new LiteralControl( "<li>"));
MyControl.Contr ols.Add(btn);
MyControl.Contr ols.Add(new LiteralControl( "</li></ul>"));

}

<ASP:Repeater id="tabs_repeat er" DataSourceID="r epeater_datasou rce"
runat="server">
<HeaderTemplate >
</HeaderTemplate>
<ItemTemplate >
<li><%#
GenerateNavBarL ink((Eval("depa rtment_id").ToS tring()),Contai ner.ItemIndex)
%></li>
<asp:PlaceHolde r ID="PlaceHolder 1"
runat="server"> </asp:PlaceHolder >
</ItemTemplate>
<FooterTemplate >
</FooterTemplate>
</ASP:Repeater>

[Steven Cheng[MSFT]]

Hi Brad,

I agree with Alexey. However,if you want to add dynamic controls into each
repeaterItem row, you can use the "ItemCreate d" event since you can
directly get the current RepeaterItem that is being created. You can locate
existing control in each repeater item or add new controls into it at that
time:

===========
protected void Repeater1_ItemC reated(object sender, RepeaterItemEve ntArgs
e)
{
PlaceHolder ph = e.Item.FindCont rol("holder1") as PlaceHolder;
//...
}
==========

Will this help for your case?

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

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

[Brad Baker]

Thank you for the overwhelming response! :) It's a bit complicated to
explain but I have to use <uland <li- it's a requirement of another app
I am integrating with. I can't do anything about that.

I abbreviated my example below for simplicity sake but the function I am
calling actually does more. I think I have managed to adjust most of my
code but I am having some difficulty with:

int intSiteNum = e.Item.ItemInde x; //this seems to work
DbDataRecord objRow = (DbDataRecord)e .Item.DataItem; // so does this
string strdepartmentid = objRow["department _id"].ToString(); // this craps
out

I am getting: "Object reference not set to an instance of an object" on the
third line above.

I haven't used the DbDataRecord datatype before so maybe I am using it
incorrectly. Basically as the repeater iterates I need to grab the value of
department_id and run some conditional logic on it which dictates formatting
on the output.

"bruce barker" <no****@nospam. comwrote in message
news:uz******** ******@TK2MSFTN GP04.phx.gbl...

you are trying to access the placeholder before its been added to the
repeater. use the itemdatabound event instead.

-- bruce (sqlwork.com)
Brad Baker wrote:

>I am trying to programmaticall y set a placeholder control in csharp which
is nested inside a repeater control between <ItemTemplatean d
</ItemTemplatetag s, however I am running into problems. I've tried
several different approaches for finding the placeholder:

This:
MyControl = this.FindContro l("$form$tabs_r epeater$PlaceHo lder1");

Produces this error:
Object reference not set to an instance of an object.
This:
MyControl =
(PlaceHolder)t abs_repeater.It ems[intSiteNum].FindControl("P laceHolder1");

Produces this error:
Index was out of range. Must be non-negative and less than the size of
the collection. Parameter name: index
Below is an abbreviated excerpt of my code. Can anyone suggest what I
might be doing wrong?

Thanks,
Brad
protected string GenerateNavBarL ink(string currentdepartme ntid, int
SiteNum)
{
int intSiteNum = SiteNum;
string strdepartmentid = currentdepartme ntid;

LinkButton btn = new LinkButton();
btn.ID = "LinkButton 1";
btn.Command += new_department_ button_Click;
btn.Text = "Add Department +";

Control MyControl = new Control();

// Two different ways of updating the place holder
//MyControl =
this.FindContr ol("form$tabs_r epeater$PlaceHo lder1");
//MyControl =
(PlaceHolder)t abs_repeater.It ems[intSiteNum].FindControl("P laceHolder1");

MyControl.Contr ols.Add(new LiteralControl( "<li>"));
MyControl.Contr ols.Add(btn);
MyControl.Contr ols.Add(new LiteralControl( "</li></ul>"));

}

<ASP:Repeate r id="tabs_repeat er" DataSourceID="r epeater_datasou rce"
runat="server" >
<HeaderTemplate >
</HeaderTemplate>
<ItemTemplate >
<li><%#
GenerateNavBar Link((Eval("dep artment_id").To String()),Conta iner.ItemIndex)
%></li>
<asp:PlaceHolde r ID="PlaceHolder 1"
runat="server" ></asp:PlaceHolder >
</ItemTemplate>
<FooterTemplate >
</FooterTemplate>
</ASP:Repeater>

[Steven Cheng[MSFT]]

Hi Brad,

As for the following error you encountered:

========
I am getting: "Object reference not set to an instance of an object" on the
third line above.
========

I think you can check the object's type and local variable to see whether
they're of the expected type and casted to the correct instance? If
possible you can set breakpoint in the code and check the value in
debugger.

Also, when you accessing the dataitem from e.Item.DataItem (in template
databound control), you need to make sure what's the datasource you use to
bind. If you're using Dataset/DataView, the "dataItem" is instance of
"DataRowVie w", if datasource is "Datareader ", the dataitem instance will be
of "IDataRecor d" type.

Please feel free to post here if you have any other finding or question on
this.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead
This posting is provided "AS IS" with no warranties, and confers no rights.

[Brad Baker]

I ended up using the following code (in case this helps someone else out in
the future)

// Here we are getting the department id
DataRowView objRow = (DataRowView)e. Item.DataItem;
string strdepartmentid = Convert.ToStrin g(DataBinder.Ev al(objRow,
"department_id" ));

Thanks for all the help. :)
Brad
"Steven Cheng[MSFT]" <st*****@online .microsoft.comw rote in message
news:IQ******** ******@TK2MSFTN GHUB02.phx.gbl. ..

Hi Brad,

As for the following error you encountered:

========
I am getting: "Object reference not set to an instance of an object" on
the
third line above.
========

I think you can check the object's type and local variable to see whether
they're of the expected type and casted to the correct instance? If
possible you can set breakpoint in the code and check the value in
debugger.

Also, when you accessing the dataitem from e.Item.DataItem (in template
databound control), you need to make sure what's the datasource you use to
bind. If you're using Dataset/DataView, the "dataItem" is instance of
"DataRowVie w", if datasource is "Datareader ", the dataitem instance will
be
of "IDataRecor d" type.

Please feel free to post here if you have any other finding or question on
this.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead
This posting is provided "AS IS" with no warranties, and confers no
rights.