Validate TextBox For Digits and Texts VB.NET

imports System.Text.RegularExpressions

 // For Text Only

 If Not Regex.Match(TextBox1.Text, "^[a-z]*$", RegexOptions.IgnoreCase).Success Then

    MsgBox("Please enter text only.")

    TextBox1.Focus()

  End If

// For Digits Only 

 If Not Regex.Match(TextBox1.Text, "^[0-9]*$", RegexOptions.IgnoreCase).Success Then

    MsgBox("Please enter Digits only.")

    TextBox1.Focus()

  End If