Validate if any of 10 Checkboxes are checked

You can't use a requiredfieldvalidator.  You could write a custom validator

If you are working with masterpages, then you can do this
Add a label to you page and rename the checkboxs from CheckBox1 to CheckBox10

       For x As Byte = 1 to 10
           Dim ctrl As Control = FindControl("ctl00$ContentPlaceHolder1$CheckBox" & x.ToString)
            If (Not ctrl Is Nothing) Then
                If CType(ctrl, CheckBox).Checked Then
                    '  At least one checked
                    Exit For
                End If
            End If
        Next X

mrichmon,
Thank's then I need help using it with a CustomValidator :). Never placed one.

jpaulino,
Thank's I will try it. It looks familiar to the other loop I used. Then the main question is how I connect this to fire the validator IF no boxes are enabled?

Would there be possible to set a RequiredFieldValidator on the textbox. Then set CausesValidation of the textbox to False, if the loop through textboxes says "noone checked", when clicking the button? Or is this check of causesvalidation occuring to late?

Regarding the loop, it simply refuse to get in this part of loop (same with the other loop I tried)
..
                If CType(ctrl, CheckBox).Checked Then
                    '  At least one checked
                    Exit For
                End If
..
I break the code, step through the loop, checking boxes and tries.

Is this correct ?

Does your structure as MasterPage and ChildPage ? This is for that check if this is correct.

"ctl00$ContentPlaceHolder1$CheckBox" & x.ToString

If is just a simple page you can try this:
For x As Byte = 1 to 10
       
         Dim ctrl As Control = FindControl("CheckBox" & x.ToString)
            If (Not ctrl Is Nothing) Then
                If CType(ctrl, CheckBox).Checked Then
                    '  At least one checked
                    Exit For
                End If
            End If
        Next X

I have only a standard webform, no masterpage.

xersoft! Thank's this was really an nice-to-go-howto. But mu button_click even seems to occur before the CustomValidators event CustomValidator1_ServerValidate are fired.. so this validation is never being evaluated. Am I missing something?

Check the ValidateEmptyText property on the custom validator. If that's FALSE you could have that happen. Make sure you set it to True.

After checking that property are you still getting the button click handler running first?

It's set to true, as you told in your steps. And yes, i'm stepping from breakpoints.

I've checked with an another EE-question where someone telled this
<asp:CustomValidator ID="CustomValidator1" runat="server"
            ControlToValidate="txtS3_11" ErrorMessage="CustomValidator"
            ValidateEmptyText="True"></asp:CustomValidator>

should be

<asp:CustomValidator ID="CustomValidator1" runat="server"
            ControlToValidate="txtS3_11" ErrorMessage="CustomValidator"
            ValidateEmptyText="True" OnServerValidate="CustomValidator1_ServerValidate"></asp:CustomValidator>


And now the code steps correctly into this event! Then it isn't fire the validator, instead it's fulfill the button_click event (continue to next page).

If I check any checkbox AND wrote something in the textbox, the customvalidator_servervalidate is bypassed.
If I don't press any checkbox, BUT wrote something in the textbox, it's also bypass the servervalidate event.

IF I don't check any checkbox and don't write anything in the textbox -- The servervalidate event is fired.
IF I check a checkbox and don't write in the textbox, the servervalidate event are fired.

Is this helping you, helping me forward?

As I understand it you want the page to be invalid if and only if, no checkboxes are checked and the textbox is empty. Keeping that in mind.


If I check any checkbox AND wrote something in the textbox, the customvalidator_servervalidate is bypassed.
-This is valid because at least one checkbox is checked.


If I don't press any checkbox, BUT wrote something in the textbox, it's also bypass the servervalidate event.
-This is valid because although there are no check boxes, there is something in the text box.


IF I don't check any checkbox and don't write anything in the textbox -- The servervalidate event is fired.
-This is an invalid situation because all checkboxes are empty and the textbox is empty.

IF I check a checkbox and don't write in the textbox, the servervalidate event are fired.
This is valid because at least one checkbox is checked.


What do you desire to happen in each of these situations? I was only basing my response on your initial question.