Getting Options collection from Select Box in ASP.

[bafadam]

I've been wracking my brains trying to figure out how to do this, so I thought I would pop it out here for the experts, since my earlier attempts have ended in failure.

I'm trying to retrive a collection of <OPTION>'s from an HTML select list, and then loop through them to make them options in a CheckBoxList in VB.

Does anyone have a quick and dirty way to use Javascript to get this information, and then loop through it in VB to populate the drop down?

I'm not very strong in using Javascript inside my VB, so I think that's where the source of my issues come from.

Thanks!

[Frinavale]

I've been wracking my brains trying to figure out how to do this, so I thought I would pop it out here for the experts, since my earlier attempts have ended in failure.

I'm trying to retrive a collection of <OPTION>'s from an HTML select list, and then loop through them to make them options in a CheckBoxList in VB.

Does anyone have a quick and dirty way to use Javascript to get this information, and then loop through it in VB to populate the drop down?

I'm not very strong in using Javascript inside my VB, so I think that's where the source of my issues come from.

Thanks!

Why can't remove the <select> list and replace it with a dropDownList?

-Frinny

[bafadam]

Why can't remove the <select> list and replace it with a dropDownList?

-Frinny

I want to have a checkboxlist that will retain the values and give the users a better multiple selection list than the standard drop down list.

Since I'm embedding this in another app that autogenerates the select list, I have to have that and that's where I plan on getting the initial values.

[Frinavale]

I want to have a checkboxlist that will retain the values and give the users a better multiple selection list than the standard drop down list.

Since I'm embedding this in another app that autogenerates the select list, I have to have that and that's where I plan on getting the initial values.

Sounds like an interesting project.

The only thing I can think of right now is make a hidden field and store the values from the <select> list into it. Then grab the hidden field in your data in your .NET code and parse it to generate your checkBoxList:

Eg...create a hidden field in your form
->you can do this in your .Net code using ClientScript.RegisterHiddenField("idOfHiddenField" ,"intialValue")

Then use your JavaScript to populate this hidden field (just add all the values of each option in your select list separated by some delimiter)

Then in your server side code grab the hidden field value:

Dim value As String = postCollection(IdOfHiddenField)

Then use the String.Split('delimiter') on your hidden field ...
Since it's your JavaScript that will generate the value for the hidden field you know what its value is delimited by.

Hope you see where I'm going with this....hope this helps!

-Frinny

[bafadam]

What is the PostCollection? It doesn't seem to be a method I can access directly, is it a member of something else I have to reference?

I won't use a hidden field because I plan on hiding the select box after I get the values out of it.

[Frinavale]

What is the PostCollection? It doesn't seem to be a method I can access directly, is it a member of something else I have to reference?

I won't use a hidden field because I plan on hiding the select box after I get the values out of it.

Oh.....
This is more complicated than I thought.
PostCollection is a parameter passed in to a method that I was using for reference during my last post...

The method is

Private Function LoadPostData(ByVal postDataKey As String, ByVal postCollection As NameValueCollection) As Boolean Implements IPostBackDataHandler.LoadPostData

It was created to satisfy my implementation of the IPostBackDataHandler interface.

Give me a minute and let me see if there is a way to do this without having to implement this interface.

-Frinny

[Frinavale]

Ok its easier than I thought...use your Request object's Params property to retrieve the parameters passed to your application.

Eg. C#:

String strValue = Request.Params["KeyName"];
 

VB:

 Dim strValue As String = Request.Params("KeyName")

Just remember that hidden fields can be changed by a malicious user so be sure to validate the input you grab from your Request object.

Cheers!

-Frinny

[Frinavale]

What is the PostCollection? It doesn't seem to be a method I can access directly, is it a member of something else I have to reference?

I won't use a hidden field because I plan on hiding the select box after I get the values out of it.

Oh,
How do you plan on hiding the select box after you get the values out of it?
I thought it was part of someone else's code?

[bafadam]

Oh, I can run javascript against the fields that are currently on the form, and can run scripting against the IFRAME that is showing this ASP.Net control.

Is that one of those pieces of information that makes this all a lot easier?

If I could use javascript to grab the options collection and then populate the checkbox list with that, then that would work for me as well, but I didn't think that could be done...

[Frinavale]

Oh, I can run javascript against the fields that are currently on the form, and can run scripting against the IFRAME that is showing this ASP.Net control.

Is that one of those pieces of information that makes this all a lot easier?

If I could use javascript to grab the options collection and then populate the checkbox list with that, then that would work for me as well, but I didn't think that could be done...

I don't know if it can be done without first storing it into a hidden field which your .Net code can access and populate the check box from there...