In Visual Basic .NET, the Until keyword is used to create a loop that will continue executing statements until a particular condition is met. The syntax for using the Until keyword is:
Do Until condition
' statements
Loop
Here, the code inside the loop will execute repeatedly until the condition is true.
Here is an example that uses the Until keyword to print a list of numbers from 1 to 10:
Dim i As Integer = 1
Do Until i > 10
Console.WriteLine(i)
i += 1
Loop
In this example, the loop will keep executing until the value of i is greater than 10. The loop executes the Console.WriteLine(i) statement, which prints out the current value of i, and then increments the value of i.
Another example that uses the Until keyword is to read input from the user until they enter a specific value:
Dim input As String = ""
Do Until input = "quit"
Console.WriteLine("Enter some input (or 'quit' to quit): ")
input = Console.ReadLine()
Loop
In this example, the loop keeps executing until the user types in "quit". The loop prompts the user to enter some input, reads their input using Console.ReadLine(), and sets input to the value entered by the user. The loop then checks if input is equal to "quit" and if it is, the loop ends and the program exits.