How to keep the colour in dropdownlist after postback

Hi I am a new to asp.net. I created a dropdwonlist and add colours t
Hi I am a new to asp.net. I created a dropdwonlist and add colours to the items. But the colours will lose after the postback. After googled, I knew it is because the attributes specified for the dropdownlist were not saved in ViewState and also found the code to Overriding SaveViewState() and LoadViewState(object) from http://aspnet.4guysfromrolla.com/articles/110205-1.aspx.
But after I copy the code to my web application to create a new class, there are so many error massages. I have spend two days to find the solution, without much success.
Please help me an give some idea
Thanks in advance.
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