Using C# windows application form, create a form that gets the input from a user from 0-100. You will need to make 3 methods for this application.

Your first method must get the users input and validates that the entry is valid. Use logic to ensure the input is accurate, if the user enters an invalid entry throw a message box to the user with the error. The user must have a successful entry to proceed.

Once the score is validated send the score to a second method which assigns a letter grade. Use the following grading schema and use integer values for your scoring. < 60 is a F, >= 60 and < 70 is a D, >= 70 and < 80 is a C, >= 80 and < 90 is a B, >= 90 is an A.

Once a grade is assigned pass the score and the letter grade to a Third Method. The third method will handle display and concatenate the results into a single string