[Webinar] Streamline your web hosting managementRegister Today

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 252
  • Last Modified:

Set Selected Value on Multiple Dropdowns - which depend on each other

I am pulling data out of a database into a form for en 'edit' administrative section.

I select my data etc..
I populate my textboxes just fine.

There is one textbox in particular 'zip_code' which is what another 'county' dropdown(sqldatasource) rely on for its values

Then there is a 'city' dropdown whos datasource depends on the value of 'county' for its values.

For the edit page workflow, id like the default values on page load (not postback) to populate with the values that have been written into the database.

so - i have tried looping throuh the controls and tetting the textbox.text values or dropdown.selectedvalue = datareader value

I get as far as county, but then city _will not_ auto select.
My best guess on this is that the sqldatasource webcontrols do thier stuff _after_ the Sub Page_Load?  which is causing my problems?
Im probably wrong though..
Anyone have any idea how i can resolve this with out digging too deep into codebehinds?
Id rather not have to build dropdown lists by hand every time the page loads.
(example, user edits the zip_code and now a whole new set of issues arrises)

an ideal solution is one where the datasource webcontrols cause the dropdowns to 'just work' and enable viewstate keeps selected values across postbacks as long as the zip code doesnt change, in which case they select new values anyways (and it keeps them)

Thanks!

0
EchoBinary
Asked:
EchoBinary
  • 4
  • 2
  • 2
1 Solution
 
Bob LearnedCommented:
There is always the Atlas ToolKit and the Cascading DropDown Control:

The "Atlas" Control Toolkit helps you bring your websites to life!
http://atlas.asp.net/default.aspx?tabid=47&subtabid=477

Bob
0
 
EchoBinaryAuthor Commented:
Awesome site! however not something i can use right now.
I will look into that for the future.    any further advice?
0
 
Bob LearnedCommented:
Do you want to do all this without post-backs?

Bob
0
The new generation of project management tools

With monday.com’s project management tool, you can see what everyone on your team is working in a single glance. Its intuitive dashboards are customizable, so you can create systems that work for you.

 
EchoBinaryAuthor Commented:
i dont mind the postbacks at the moment  - but id like it to work as described
v2.0 will b w/o postbacks  

deadlines..  you know  ;)
0
 
nauman_ahmedCommented:
No need to loop through the controls. Make sure that you use a If(!Page.IsPostBack) before you call your binding routine in page_load event:

private Page_Load(object src, EventArgs e)
{
  if (!Page.IsPostBack)
  {
      BindControlsForEditing();
   }
}

I am assuming you have a separate editable section for your records. If it is so, your workflow should look like this.

1. Connect to database

2. Get Records

3. Populate the value for the parent field. If it is a listbox or drop down that has several values already populated, then seet its selected index as follows:

MyListBox.SelectedIndex = MyListBox.Items.IndexOf(MyListBOx.Items.FindByValue("PARENT_FIELD_VALYE"));

Once you have set the selected index, it will stay selected between post-back as long as user do not select a different value.

4. Depending on the value of parent field, populate the value of child field.

5. Populate another parent field.

6. Depending on the value of parent field, populate the value of child field.

and so on. If you have a text-field like zip-code field that is a parent for another field, you can write an evenhandler for TextChanged event and then bind the approprite child control.

HTH, Nauman.
0
 
EchoBinaryAuthor Commented:
Upon further investigation i am forced to wonder if there is an order of operations issue going on.

The code that tells the dropdown which to select by default is in (obviously) a code behind.
The dropdowns are databound to asp controls on the page itself. is it poss. that the databinding is happening _after_ the codebehind gets run?
0
 
nauman_ahmedCommented:
Yes. Databinding for dependent text-box is mostly handled when the selected index is changed for parent drop-down. Check the SelectedIndexChanged event for the parent drop-down to see if it has additional code.

--Nauman.
0
 
EchoBinaryAuthor Commented:
My solution was to realize what the order of operations is/was for the page. as such ill give pts to nauman for answering that part
0

Featured Post

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

  • 4
  • 2
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now