how to call a function from .aspx.cs file to .aspx file

hi all,

I  am developing a web application.I have to call a function from .aspx.cs file to .aspx file. I have written the function in .aspx file.I want to pass the parameter from the .aspx.cs file to the function which is in .aspx file. How can i call function from the .aspx.cs file to .aspx file.Please help me regarding this..

thanks in advance.
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