DropDown List and user input

jlandan2 · August 11th, 2013, 07:10 AM

I am sorry for my jargon. I used term "run" in meaning of debugging. When I debug with "selectedValue" property in my dropdownlist, I get the following error in my browser. But if I delete the "selectedValue" from my dropdownlist, there is no error. But the value wont entering the database. It'll return null in the database.

Code:

Server Error in '/WebSite1' Application.
'ddlStatus' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentOutOfRangeException: 'ddlStatus' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

I hope my explanation can help u in figuring my error.

Imar · August 11th, 2013, 07:31 AM

Quote:

'ddlStatus' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value

Aha, but this means something completely different.

This error shows that your code works fine, but that the data you try to preselect in the drop down does not exist.

There could be two reasons for this:

1. The Status column in the database contains a value that is not New, Pending or Complete. This would be the case if it was null.

2. The database is bound dynamically, but you haven't called DataBind yet (and thus its Items collection is still empty). In that case call DataBind() on the drop down before you do other binding.

Hope this helps,

Imar

jlandan2 · August 11th, 2013, 07:40 AM

Thank you for your reply :) It does help me understand the error.

But I'm unable to understand point no.2.

Code:

2. The database is bound dynamically, but you haven't called DataBind yet (and thus its Items collection is still empty). In that case call DataBind() on the drop down before you do other binding.

How can I called databind specifically for this dropdownlist?

Imar · August 11th, 2013, 07:42 AM

You may not have to as it's a static list, isn't it? I mean, the items are not coming from a database are they?

My guess is that your data in the database is incorrect. I think you fix it by deleting or updating existing data. Then use a drop-down for the Insert template as well so you can't insert invalid values anymore.

Cheers,

Imar

jlandan2 · August 11th, 2013, 08:05 AM

My data is indeed a static list. As you can see in my code, it was previously using a textbox as editing method & binding the data. It works fine if I edit it through textbox. But I was required to use dropdownlist to control the data entered, problems occured. So, I guess my database is fine.

I tried using your tips by insert the same dropdownlist in my insert template, but the same error still come up. The error still comeout as below.

Code:

ddlStatus' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value

can you give me an example of code to fix this?

Imar · August 11th, 2013, 08:30 AM

Quote:

I tried using your tips by insert the same dropdownlist in my insert template, but the same error still come up.

For the InsertTemplate? Or for Edit? For the Insert you can't use this as there is no selected data to use. For the Edit template, it could mean your data is still incorrect.

Quote:

can you give me an example of code to fix this?

Take a look at the Status column in the database for your existing records. What data does it contain? I am guessing there is a value that does not exist as an item in your drop-down list.

Imar

jlandan2 · August 11th, 2013, 09:19 AM

inside my Status column, there is "Null" for the particular status I am editing.

For example, data with ID 1 with Status "New" . But then I want to edit it to "Pending". So I chose "Pending" from my dropdownlist.

Then the formview view nothing in my formview. When I checked the database, it ha "Null" in it.

Do I need coding behind the page, cos I dont have one (since I am not pretty good at coding behind the page)..

And I am using VB with ASP.Net 3.5

Imar · August 11th, 2013, 09:22 AM

Is Null a valid state? If not, I would do this:

1. Manually correct the data in the database.

2. Use a DropDownList in the Insert template so users cannot accidentally insert null anymore.

If it is valid state, you could normalize it to an empty string in the SQL statement (using COALESCE) and then add an item to the drop down list that has a value of an empty string.

Cheers,

Imar

jlandan2 · August 11th, 2013, 09:38 AM

I really wish I can understand what you said here, but it did not ring the bells.

If I email to you the whole entire website (its just a simple website) including the database, will you help me to look at it. Its in the page called PaparAduan.aspx

Please please please help me.

P/S: May be not the entire website, just the relevant pages & database.

Imar · August 11th, 2013, 09:44 AM

Before we do that, answer one question:

Is Null a valid state for the Status column? That is, do you want to allow Null?

If not, just go to your database, and replace each occurrence of null in something like New in the Status column.

That should fix the problem, shouldn't it?

Imar