Substring in Vb.Net String Class returns a new string that is a substring of this string. The substring begins at the specified given index and extended up to the given length.

Public Function Substring(ByVal startIndex As Integer, ByVal length As Integer) As String

Parameters:

startIndex: The index of the start of the substring.

length: The number of characters in the substring.

Returns:

The specified substring.

Exceptions:

System.ArgumentOutOfRangeException : the beginIndex or length less than zero, or the begin index + length not within the specified string

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click

        Dim str As String
        Dim retString As String
        str = "This is substring test"
        retString = str.Substring(8, 9)
        MsgBox(retString)

    End Sub
End Class