The Length() function in String Class returned the number of characters occurred in a String.

System.String.Length() As Integer

Returns:

Integer : The number of characters in the specified String

For ex:

"This is a Test".Length() returns 14.

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
        Dim str As String
        str = "This is a Test"
        MsgBox(str.Length())
    End Sub
End Class