How can I access buttons using string Ids in ASP.Net?

[freetreaf]

I am using Asp.Net. I have a page full of buttons and every button has an id example: btn_1_1, btn_1_2 etc. From the code side I have a loop and I am generating the button's Ids as a string using random numbers, example: "btn_1_1", "btn_1_2" etc. . My question is, how I can use this string value to access the button's properties that have the same ID?Thanks