Accessing controls from the mainpage in a class

Hello Every one, in a asp.net project i have a text box on the mainPage "Textbox1". I have created a class "TextTool.cs" that resides in the App_Code folder. the class in called on a button click event i.e. when a user enters some text in the text box on the main page and clicks the button, the text is added to webpage at some defined pixels. in the class i have a property
textElement.text = "?????";
where i need to pass the text entered by the user in the textbox on the main page to this property to add it to the webpage. can any one tell me how can i do that??? how can i get the text entered by the user in the textbox on the main page and pass it to the property in the class??
Regards,
Usman
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