" src="/emoticons/emotion-9.gif"> Can someone help me with the following problem.

The dropdownlist raises always the following exception when the binded field has a value that doesn't exist in the list of values.

'DropDownList' has a SelectedValue which is invalid because it does not exist in the list of items.

As it is possible for the user to change the values of the list (in a codetable) it is possible that an earlier selected item not exists anymore. Then i would select an default item.

(I tried already to create an custom dropdown control an override the databinding procedure but then the postback information get lost.)

How can i handle this exception?

'DropDownList' has a SelectedValue which is invalid because it does not exist in the list of items.

I am assuming you are trying to programatically set the selectedvavlue. If I understand you correctly, try this to see if it will work:

add this to your code

try
dropdownlist.selectedvalue = theselectionthepersonmakes
catch ex as exception
present them with a statement that the selected value no longer exists.
end try

I do not know what you are using this for, so I am not sure if it will work for you, but this should prevent the page from erroring out on them.

protected override void OnDataBinding(EventArgs e)
{
   try{base.OnDataBinding(e);}

   catch (ArgumentOutOfRangeException ex){
      this.ClearSelection();
      ListItem li = new ListItem("Value not exists in valuelist", "-99");
      li.Selected = true;
      this.Items.Insert(0, li);
   }

}

I have the same problem but how do you make it works. thanks. I got these errors.

Error 1 'Form1' does not contain a definition for 'ClearSelection'  

Error 2 'System.Web.UI.WebControls.ListItem' does not contain a definition for 'ClearSelection'  

Error 3 'System.Collections.IDictionary' does not contain a definition for 'Insert'  

asp dropdownlist sucks :: the blog

http://aspddlsucks.spaces.live.com/

    You might consider EasyListBox, which not only doesn't throw an error, but also keeps the value if you've set it before the list is populated.  Then when the items are added, it tries again to see if it can select the value you want.

    If cost is a problem, you can get a really cheap license through DotNetCharity right now ($10/$20 for a single-website version).
 

Just FYI

I had the same problem in a gridview template with dropdownlist and all it took was for me to enable the postback on the dropdownlist.  Go figure.

supersven:

I had already found an solution for my problem: Override the DataBinding method and catch the exception.

I much better way than catching an exception is to first check if your value exists in the dropdownlist on databound.

Details here: http://blog.evonet.com.au/post/2008/06/07/dropdownlist1-has-a-SelectedValue-which-is-invalid-because-it-does-not-exist-in-the-list-of-items.aspx

Bartek

A workaround that worked fine for me was setting the SelectedValue to null...

DropDownList1.DataSource = MyDataSource;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.DataBind();

This throws the -- 'DropDownList1' has a SelectedValue which is invalid because it does not exist in the list of items.
Parameter name: value --

If I simply add the "DropDownList1.SelectedValue = null;" it works fine:

DropDownList1.DataSource = MyDataSource;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.SelectedValue = null;
DropDownList1.DataBind();

Hope this works fine for U too guys...

Where did you put this code? An event of the ddl or somewhere else?

Most of these kind of issue with drop down is due to it not getting binded again after post back. So your dropdown has no value when you call the event with dropdown.Selected value. Bind the dropdown again in

if  page.Ispostback then

'bind dd

Lots of times, the individual is binding an object or SQLDataSource to a dropdown list.   When the datasource tries to read the value from the dropdownlist the first time, there is no value set on the dropdownlist therefore you get an exception.   One way to bypass this is to set a default value on the dropdownlist on it's databound event like this "ddl.items.insert(0, new Item("Select Item", "1");".  1 is the value in this case, "Select Item"  is what the ddl displays to the user.  The value in this case is a row ID.  The default value should be a valid data type that  the datasource can read even if it doesn't exist.

As the person aboved mentioned, this is generally when you're using "Bind" on your dropdown box, and it's a null value.   The easiest way I know of to get around this is to add <ListItem Text="no value" value="" />  as an item in your dropdown list, and set AppendDataBoundItems = true

This will then select the "no value" list item for database values that are null.  This is much simpler than the solutions above, and less complexity means less chances for these to go awry.

 An excellent article on this subject is below.

http://msdn.microsoft.com/en-us/library/ms366709.aspx

Here is an example of what I mean.

<asp:DropDownList ID="ddlEmployees" AppendDataBoundItems="true" SelectedValue='<%#Bind("EmployeeId") %>' runat="server" DataSourceId="ldsGetEmployees" DataTextField="FullName" DataValueField="EmployeeId">
                <asp:ListItem Text="none" Value=""></asp:ListItem>
</asp:DropDownList>