We can do that via Custon Validator Control on ASP. But the solution I posted for Checkbox validation is much more simple I guess What do you think? You can simply download the dll, inlcude it in the Visual Studio (Web Developer) Toolbox and then you can drag and drop it anywhere you like, so it is a simple to use as any other validation control, including client and server side validation as you would expect from a validator control.Net 3.5 Toolbar on the first examples and on the second one we are able to that manually ! It also works with the Validation Summary control... It's really helpful for me and helped me lot to complete my task. I had found another nice post over the internet which was also explained very well about Validating File Upload control for specific file type and required field, for more details of this post check out this link... There are few links that also helpful for developers.It first gets the Check Box List and its internal Check Boxes and then a loop is executed to check whether the Check Boxes are checked or unchecked. Now you can ask questions directly to me on my new site ASPForums.
If you then click the button when the checkbox is checked, you should see no errors.
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If the length is 0 (zero), we alert the user and prevent the user from submitting the form using e.prevent Default().
Net has bunch of useful validation controls and they realy make our project so easy in terms of validations. Net doesn't have any control to validate a check box !
Please review the following specific error details and modify your source code appropriately.