What code would you use in c# in visual studio to get the number from a text box and use an add button to add that number to an array

Clicking of the Add number to array button. The operation of this button will be to validate the contents of the text box and place the contents into an array of numbers if the contents is a number between -1,125 and 1,125. If the number is less than -1,125 then it is considered to be too small If the number is greater than 1,125 then it is considered to be too big