Below is a simple approach on how to reset all form field values .I had to use this approach to reset all fields after submit button was clicked .
The code above is self explanatory as all its doing is looping through each controls and sub controls within the controls.If the control type matches then it clears the input,selection .
The sample above looks for Textbox,Dropdownlist and Checkbox controls .You can easily expand it to include other controls .
You can call the method from :
ii) Control level
Be careful though while calling the method from Page level as it caused an out of memory exception in my case
For other approaches on resetting from input fields , please refer to ScottGu’s blog post