Multiple DropDownLists

**David Wier** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

ddl.items.clear

David Wier

http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML with no
bloated markup

"Igor" <igorm@live.com wrote in message
news:22BA969D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...

Hello
>
I have the following problem. I have three drop down lists on my page.
They are filled with data from a database. Initially only the first one is
enabled. The next one is enebled when user selects an item from the first
one -- it is then filled with data specific to the selection in the drop
down list above. The same with the third one. For each drop down list the
first item is always "--select an item--" (as described here:
http://weblogs.asp.net/scottgu/archi...9/436804.aspx). To enable
that I had to set the AppendDataBound Items property for all three drop
down lists to "true". Unfortunatelly, when a user selects an item from the
first drop down list, the second one gets filled with item "--select an
item--" and data from the database. But if the user changes their mind and
selects different item from the first list (or list above in the
structure) the next drop down list gets filled with new data, but, because
of the AppendDataBound Items property set to "true", previous data remains
in the list. Thus, I must clear list(s) when user makes change to the
selection above in the structure. How can I do this?
>
Kind regards
>
IgorM

**Igor** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

Hi

I didn't make myself clear enough. Where should I put it in the code ? I
tried putting it in SelectedIndexCh anged events of particular drop down
lists as well as PageLoad event but than I had a problem with a statement
that selects first item (the one with "--select item --" text ) in the drop
down lists below in the hierarchy because it fired exceptions. By
ddl.items.clear the first item, the "--select item--" is also cleares, and
it is not added again in postbacks.

Kind regars
IgorM

"David Wier" <dw@dw.comwro te in message
news:%23GwEyeJz IHA.2208@TK2MSF TNGP04.phx.gbl. ..

ddl.items.clear
>
David Wier

http://aspnet101.com

http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML with
no bloated markup
>
>
"Igor" <igorm@live.com wrote in message
news:22BA969D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...

>Hello
>>
>I have the following problem. I have three drop down lists on my page.
>They are filled with data from a database. Initially only the first one
>is enabled. The next one is enebled when user selects an item from the
>first one -- it is then filled with data specific to the selection in the
>drop down list above. The same with the third one. For each drop down
>list the first item is always "--select an item--" (as described here:
>http://weblogs.asp.net/scottgu/archi...9/436804.aspx). To enable
>that I had to set the AppendDataBound Items property for all three drop
>down lists to "true". Unfortunatelly, when a user selects an item from
>the first drop down list, the second one gets filled with item "--select
>an item--" and data from the database. But if the user changes their mind
>and selects different item from the first list (or list above in the
>structure) the next drop down list gets filled with new data, but,
>because of the AppendDataBound Items property set to "true", previous data
>remains in the list. Thus, I must clear list(s) when user makes change to
>the selection above in the structure. How can I do this?
>>
>Kind regards
>>
>IgorM

>
>

**David Wier** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

You should put it anywhere you need it, in any event handler, just before
you're populating the ddl.
Anothere thing - if you're populating any ddls in the Page_Load event, be
sure to surround that population with an if/then/Postback block

David Wier

http://aspnet101.com

http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML with no
bloated markup

"Igor" <igorm@live.com wrote in message
news:0D236198-A615-46CB-8100-F8982695CB8E@mi crosoft.com...

Hi
>
I didn't make myself clear enough. Where should I put it in the code ? I
tried putting it in SelectedIndexCh anged events of particular drop down
lists as well as PageLoad event but than I had a problem with a statement
that selects first item (the one with "--select item --" text ) in the
drop down lists below in the hierarchy because it fired exceptions. By
ddl.items.clear the first item, the "--select item--" is also cleares, and
it is not added again in postbacks.
>
Kind regars
IgorM
>
"David Wier" <dw@dw.comwro te in message
news:%23GwEyeJz IHA.2208@TK2MSF TNGP04.phx.gbl. ..

>ddl.items.clea r
>>
>David Wier
>http://aspnet101.com
>http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML with
>no bloated markup
>>
>>
>"Igor" <igorm@live.com wrote in message
>news:22BA969 D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...

>>Hello
>>>
>>I have the following problem. I have three drop down lists on my page.
>>They are filled with data from a database. Initially only the first one
>>is enabled. The next one is enebled when user selects an item from the
>>first one -- it is then filled with data specific to the selection in
>>the drop down list above. The same with the third one. For each drop
>>down list the first item is always "--select an item--" (as described
>>here: http://weblogs.asp.net/scottgu/archi...9/436804.aspx). To
>>enable that I had to set the AppendDataBound Items property for all three
>>drop down lists to "true". Unfortunatelly, when a user selects an item
>>from the first drop down list, the second one gets filled with item
>>"--select an item--" and data from the database. But if the user changes
>>their mind and selects different item from the first list (or list above
>>in the structure) the next drop down list gets filled with new data,
>>but, because of the AppendDataBound Items property set to "true",
>>previous data remains in the list. Thus, I must clear list(s) when user
>>makes change to the selection above in the structure. How can I do this?
>>>
>>Kind regards
>>>
>>IgorM

>>
>>

>

**Igor** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

Still don't know how to get the first item to be "--select value--" in code
behind if I cannot use the <asp:ListItem Text="-- select value --"
Value="">.

"David Wier" <dw@dw.comwro te in message
news:O8XAiRKzIH A.4492@TK2MSFTN GP02.phx.gbl...

You should put it anywhere you need it, in any event handler, just before
you're populating the ddl.
Anothere thing - if you're populating any ddls in the Page_Load event, be
sure to surround that population with an if/then/Postback block
>
David Wier

http://aspnet101.com

http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML with
no bloated markup
>
>
"Igor" <igorm@live.com wrote in message
news:0D236198-A615-46CB-8100-F8982695CB8E@mi crosoft.com...

>Hi
>>
>I didn't make myself clear enough. Where should I put it in the code ? I
>tried putting it in SelectedIndexCh anged events of particular drop down
>lists as well as PageLoad event but than I had a problem with a statement
>that selects first item (the one with "--select item --" text ) in the
>drop down lists below in the hierarchy because it fired exceptions. By
>ddl.items.clea r the first item, the "--select item--" is also cleares,
>and it is not added again in postbacks.
>>
>Kind regars
>IgorM
>>
>"David Wier" <dw@dw.comwro te in message
>news:%23GwEyeJ zIHA.2208@TK2MS FTNGP04.phx.gbl ...

>>ddl.items.cle ar
>>>
>>David Wier
>>http://aspnet101.com
>>http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML
>>with no bloated markup
>>>
>>>
>>"Igor" <igorm@live.com wrote in message
>>news:22BA96 9D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...
>>>Hello
>>>>
>>>I have the following problem. I have three drop down lists on my page.
>>>They are filled with data from a database. Initially only the first one
>>>is enabled. The next one is enebled when user selects an item from the
>>>first one -- it is then filled with data specific to the selection in
>>>the drop down list above. The same with the third one. For each drop
>>>down list the first item is always "--select an item--" (as described
>>>here: http://weblogs.asp.net/scottgu/archi...9/436804.aspx).
>>>To enable that I had to set the AppendDataBound Items property for all
>>>three drop down lists to "true". Unfortunatelly, when a user selects an
>>>item from the first drop down list, the second one gets filled with
>>>item "--select an item--" and data from the database. But if the user
>>>changes their mind and selects different item from the first list (or
>>>list above in the structure) the next drop down list gets filled with
>>>new data, but, because of the AppendDataBound Items property set to
>>>"true", previous data remains in the list. Thus, I must clear list(s)
>>>when user makes change to the selection above in the structure. How can
>>>I do this?
>>>>
>>>Kind regards
>>>>
>>>IgorM
>>>
>>>

>>

>
>

**Mark Elliott** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

Would something like the following work?

DropDownList ddl = new DropDownList();
ListItem li = new ListItem("--select item--");
ddl.Items.Inser t(li);

On Thu, 12 Jun 2008 13:57:18 -0300, Igor <igorm@live.com wrote:

Still don't know how to get the first item to be "--select value--" in
code behind if I cannot use the <asp:ListItem Text="-- select value --"
Value="">.
>
>
"David Wier" <dw@dw.comwro te in message
news:O8XAiRKzIH A.4492@TK2MSFTN GP02.phx.gbl...

>You should put it anywhere you need it, in any event handler, just
>before you're populating the ddl.
>Anothere thing - if you're populating any ddls in the Page_Load event,
>be sure to surround that population with an if/then/Postback block
>>
>David Wier
>http://aspnet101.com
>http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML
>with no bloated markup
>>
>>
>"Igor" <igorm@live.com wrote in message
>news:0D23619 8-A615-46CB-8100-F8982695CB8E@mi crosoft.com...

>>Hi
>>>
>>I didn't make myself clear enough. Where should I put it in the code ?
>>I tried putting it in SelectedIndexCh anged events of particular drop
>>down lists as well as PageLoad event but than I had a problem with a
>>statement that selects first item (the one with "--select item --"
>>text ) in the drop down lists below in the hierarchy because it fired
>>exceptions. By ddl.items.clear the first item, the "--select item--"
>>is also cleares, and it is not added again in postbacks.
>>>
>>Kind regars
>>IgorM
>>>
>>"David Wier" <dw@dw.comwro te in message
>>news:%23GwEye JzIHA.2208@TK2M SFTNGP04.phx.gb l...
>>>ddl.items.cl ear
>>>>
>>>David Wier
>>>http://aspnet101.com
>>>http://iWritePro.com - One click PDF, convert .doc/.rtf/.txt to HTML
>>>with no bloated markup
>>>>
>>>>
>>>"Igor" <igorm@live.com wrote in message
>>>news:22BA969 D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...
>>>>Hello
>>>>>
>>>>I have the following problem. I have three drop down lists on my
>>>>page. They are filled with data from a database. Initially only the
>>>>first one is enabled. The next one is enebled when user selects an
>>>>item from the first one -- it is then filled with data specific to
>>>>the selection in the drop down list above. The same with the third
>>>>one. For each drop down list the first item is always "--select an
>>>>item--" (as described here:
>>>>http://weblogs.asp.net/scottgu/archi...9/436804.aspx). To
>>>>enable that I had to set the AppendDataBound Items property for all
>>>>three drop down lists to "true". Unfortunatelly, when a user selects
>>>>an item from the first drop down list, the second one gets filled
>>>>with item "--select an item--" and data from the database. But if
>>>>the user changes their mind and selects different item from the
>>>>first list (or list above in the structure) the next drop down list
>>>>gets filled with new data, but, because of the AppendDataBound Items
>>>>property set to "true", previous data remains in the list. Thus, I
>>>>must clear list(s) when user makes change to the selection above in
>>>>the structure. How can I do this?
>>>>>
>>>>Kind regards
>>>>>
>>>>IgorM
>>>>
>>>>
>>>

>>
>>

>

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**Steve C. Orr [MCSD, MVP, CSM, ASP Insider]** · Jun 27 '08, 08:09 PM

Re: Multiple DropDownLists

Perhaps you can use this free control to make your life easier:

ASP.NET Core, an open-source web development framework | .NET

http://www.asp.net/AJAX/AjaxControlToolkit/Samples/CascadingDropDown/CascadingDropDown.aspx

Build web apps and services that run on Windows, Linux, and macOS using C#, HTML, CSS, and JavaScript. Get started for free on Windows, Linux, or macOS.

--
I hope this helps,
Steve C. Orr,
MCSD, MVP, CSM, ASPInsider

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"Igor" <igorm@live.com wrote in message
news:22BA969D-A3F0-4AF7-B786-EC9B40183279@mi crosoft.com...

Hello
>
I have the following problem. I have three drop down lists on my page.
They are filled with data from a database. Initially only the first one is
enabled. The next one is enebled when user selects an item from the first
one -- it is then filled with data specific to the selection in the drop
down list above. The same with the third one. For each drop down list the
first item is always "--select an item--" (as described here:
http://weblogs.asp.net/scottgu/archi...9/436804.aspx). To enable
that I had to set the AppendDataBound Items property for all three drop
down lists to "true". Unfortunatelly, when a user selects an item from the
first drop down list, the second one gets filled with item "--select an
item--" and data from the database. But if the user changes their mind and
selects different item from the first list (or list above in the
structure) the next drop down list gets filled with new data, but, because
of the AppendDataBound Items property set to "true", previous data remains
in the list. Thus, I must clear list(s) when user makes change to the
selection above in the structure. How can I do this?
>
Kind regards
>
IgorM

Multiple DropDownLists

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