ignoring a case in C#

Question

Hi
I just want to know is there any function which simply ignores the case of a string values. I mean I have some values stored in database which is a mixture of lower and upper cases. Now in a form I have one textbox which accepts some string value and a button called "search". Upon clicking on the search button the textbox value should be taken and be compared with the value in the database. If it matches then a messagebox will popup saying successful else failure. Friends when I did this if the cases entered in the textbox exactly matches the value in the database then it shows success message otherwise even if the spelling is correct it shows unsuccessful because of cases. So is there any method to ignore the case as soon as the value in the textbox entered.
 
Thanks