Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
        Dim str As String = "This is VB.NET Test"
        Dim insStr As String = "Insert "
        Dim strRes As String = str.Insert(15, insStr)
        MsgBox(strRes)
    End Sub
End Class