Prevent URL Phone Number Email using ASP.Net Regular Expressions using C# and VB.Net

Please refer below sample.

HTML

<table>
    <tr>
        <td><asp:TextBox ID="txtInput" runat="server" /></td>
        <td><asp:Button Text="Submit" ID="btnSubmit" runat="server" OnClick="Validate" /></td>
    </tr>
    <tr>
        <td><asp:Label ID="lblOutput" runat="server" ForeColor="Red" /></td>
    </tr>
</table>

Namespace

C#

using System.Text.RegularExpressions;

VB.Net

Imports System.Text.RegularExpressions

Code

C#

protected void Validate(object sender, EventArgs e)
{
    string input = txtInput.Text;

    Regex rgxEmailId = new Regex(@"([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$");
    Match emailMatch = rgxEmailId.Match(input);
    if (emailMatch.Success)
    {
        lblOutput.Text = "Email Address not allowed.";
        return;
    }

    Regex rgxMobileNo = new Regex(@"^([0-9]{10})$");
    Match mobileNoMatch = rgxMobileNo.Match(input);
    if (mobileNoMatch.Success)
    {
        lblOutput.Text = "Mobile number not allowed.";
        return;
    }

    Regex rgxURL = new Regex(@"^(www|http|https|ftp|)\://|[a-zA-Z0-9\-\.]+\.[a-zA-Z](:[a-zA-Z0-9]*)?/?([a-zA-Z0-9\-\._\?\,\'/\\\+&%\$#\=~])*[^\.\,\)\(\s]$");
    Match urlMatch = rgxURL.Match(input);
    if (urlMatch.Success)
    {
        lblOutput.Text = "URL not allowed.";
        return;
    }
}

VB.Net

Protected Sub Validate(ByVal sender As Object, ByVal e As EventArgs)
    Dim input As String = txtInput.Text
    Dim rgxEmailId As Regex = New Regex("([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$")
    Dim emailMatch As Match = rgxEmailId.Match(input)

    If emailMatch.Success Then
        lblOutput.Text = "Email Address not allowed."
        Return
    End If

    Dim rgxMobileNo As Regex = New Regex("^([0-9]{10})$")
    Dim mobileNoMatch As Match = rgxMobileNo.Match(input)

    If mobileNoMatch.Success Then
        lblOutput.Text = "Mobile number not allowed."
        Return
    End If

    Dim rgxURL As Regex = New Regex("^(www|http|https|ftp|)\://|[a-zA-Z0-9\-\.]+\.[a-zA-Z](:[a-zA-Z0-9]*)?/?([a-zA-Z0-9\-\._\?\,\'/\\\+&%\$#\=~])*[^\.\,\)\(\s]$")
    Dim urlMatch As Match = rgxURL.Match(input)

    If urlMatch.Success Then
        lblOutput.Text = "URL not allowed."
        Return
    End If
End Sub

Screenshot