For in Visual Basic .NET

The 'for' loop in Visual Basic .NET is used to execute a block of code repeatedly for a predetermined number of times.

The syntax for the 'for' loop is as follows:

For counter As datatype = start To end [Step step]

[statements]

Next [counter]

Here, counter is a variable used to keep track of the iteration count, datatype is the data type of the counter variable, start is the initial value of the counter, end is the final value of the counter and step is the increment value of the counter on each iteration. Step is optional and if not specified, the default value is 1.

Let's look at an example:

Dim i As Integer
For i = 1 To 5
    Console.WriteLine(i)
Next

This will output the numbers 1 to 5 on the console.

Another example with Step:

Dim i As Integer
For i = 2 To 10 Step 2
    Console.WriteLine(i)
Next

This will output the even numbers from 2 to 10 on the console.

We can also use the 'for' loop to iterate through arrays:

Dim arr() As Integer = {1, 2, 3, 4, 5}
Dim i As Integer
For i = 0 To arr.Length - 1
    Console.WriteLine(arr(i))
Next

This will output the elements of the array on the console.

In conclusion, the 'for' loop is a powerful tool in Visual Basic .NET for iterating through and manipulating data in a controlled manner.