In this article i am trying to explain the validation expression that can be used in frequently used validators
<td>emailAddress</td>
<td>
<asp:TextBox ID="Temail" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="invalid email address" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*" ControlToValidate="Temail"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>Only numbers</td>
<td>
<asp:TextBox ID="Tnumbers" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator2" runat="server" ErrorMessage="Only Numbers" ControlToValidate="Tnumbers" ValidationExpression="^[0-9]*$"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>Indian Mobile Numbers</td>
<td>
<asp:TextBox ID="Tmoby1" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator3" runat="server" ErrorMessage="please include+91 to your number" ControlToValidate="Tmoby1" ValidationExpression="^((\+){0,1}91(\s){0,1}(\-){0,1}(\s){0,1}){0,1}98(\s){0,1}(\-){0,1}(\s){0,1}[1-9]{1}[0-9]{7}$"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>Indian Landline Numbers</td>
<td>
<asp:TextBox ID="Tmoby2" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator4" runat="server" ValidationExpression="\d{3,5}-\d{6,7}" ErrorMessage="areacode-phonenumber" ControlToValidate="Tmoby2"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>have only 6 elements in the text</td>
<td>
<asp:TextBox ID="Tonlysix" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator5" runat="server" ErrorMessage="only six chars" ControlToValidate="Tonlysix" ValidationExpression="\w{6,20}"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>numbers with or without special characters<p>LandLine:08655 1111111<br />
Mobile:+919844198441
</p></td>
<td>
<asp:TextBox ID="Tnumspl" runat="server" MaxLength=15></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator6" runat="server" ValidationExpression="^\+?[\d\s]+\(?[\d\s]{10,}$" ErrorMessage="only numbers" ControlToValidate="Tnumspl"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td>Only Characters</td>
<td>
<asp:TextBox ID="Tchars" runat="server"></asp:TextBox></td>
<td>
<asp:RegularExpressionValidator ID="RegularExpressionValidator7" runat="server" ErrorMessage="Only Characters" ValidationExpression="^[a-zA-Z]*$" ControlToValidate="Tchars"></asp:RegularExpressionValidator></td>
</tr>
<tr><td colspan=3 align=center >
<asp:Button ID="Button1" runat="server" Text="Button" /></td></tr>