.NET regular expressions string match replace

String match using regular expressions – VB.NET

Import Imports System.Text.RegularExpressions

            'regularExpression_Match -> regular expression pattern to macth
            Dim regularExpression_Match As New Regex("(.*)REGULAR EXPRESSION MATCH PATTERN(.*)")
            'txtInput.txt -> Text to macth against regularExpression_Match pattern
            Dim myMatch As Match = System.Text.RegularExpressions.Regex.Match(txtInput.Text, regularExpression_Match)
            If myMatch.Success Then
                'Do Something
            End If

If Regex.IsMatch( userInputString, "\d+(\.?\d+)" ) Then
    ' perform some conversion and math operations here
End If 

String replace using regular expressions – VB.NET

                    Try
                        'regularExpression_Replace -> regular expression pattern to replace
                        Dim regularExpression_Replace As New Regex("(.*)REGULAR EXPRESSION REPLACE PATTERN(.*)")
                        'txtInput.txt -> Text to macth and replace against 
                        Dim txtReplacementPattern As String
                        txtReplacementPattern = "THIS WILL BE MY REPLACED TEXT"
                        'txtReplacementPattern = "$$2 $$1"
                        txtInput.Text = regularExpression_Replace.Replace(txtInput.Text, _
                            txtReplacementPattern)
                    Catch ex As Exception
                        Mess