ASP.Net RegularExpression Validators

Maximum character length Validation (Maximum 6 characters allowed)

[xml]
<asp:TextBox ID=”TextBox1″ runat=”server”></asp:TextBox>
<asp:RegularExpressionValidator runat=”server” ID=”RegularExpressionValidator1″
Display = “Dynamic”
ControlToValidate = “TextBox1”
ValidationExpression = “^[\s\S]{0,6}$”
ErrorMessage=”Maximum 6 characters allowed.”>
</asp:RegularExpressionValidator>
[/xml]

Minimum character length Validation (Minimum 6 characters required)

[xml]
<asp:TextBox ID=”TextBox2″ runat=”server”></asp:TextBox>
<asp:RegularExpressionValidator runat=”server” ID=”RegularExpressionValidator2″
Display = “Dynamic”
ControlToValidate = “TextBox2”
ValidationExpression = “^[\s\S]{6,}$”
ErrorMessage=”Minimum 6 characters required.”>
</asp:RegularExpressionValidator>
[/xml]

Minimum and Maximum character length Validation (Minimum 2 and Maximum 6 characters required)

[xml]
<asp:TextBox ID=”TextBox3″ runat=”server”></asp:TextBox>
<asp:RegularExpressionValidator runat=”server” ID=”RegularExpressionValidator3″
Display = “Dynamic”
ControlToValidate = “TextBox3”
ValidationExpression = “^[\s\S]{2,6}$”
ErrorMessage=”Minimum 2 and Maximum 6 characters required.”>
</asp:RegularExpressionValidator>
[/xml]

Alphanumeric with special Characters
Minimum length 7 and Maximum length 10. Characters allowed – a – z A – Z 0-9 ’@ & # .

[xml]
<asp:RegularExpressionValidator ID=”RegExp1″ runat=”server”
ErrorMessage=”Password length must be between 7 to 10 characters”
ControlToValidate=” txtPassword ”
ValidationExpression=”^[a-zA-Z0-9’@&#.\s]{7,10}$” />
[/xml]

Alphanumeric Only
Minimum length 7 and Maximum length 10. Characters allowed – a – z A – Z 0-9

[xml]
<asp:RegularExpressionValidator ID=”RegExp1″ runat=”server”
ErrorMessage=”Password length must be between 7 to 10 characters”
ControlToValidate=” txtPassword ”
ValidationExpression=”^[a-zA-Z0-9\s]{7,10}$” />
[/xml]

Alphabets Only
Minimum length 7 and Maximum length 10. Characters allowed – a – z A – Z

[xml]
<asp:RegularExpressionValidator ID=”RegExp1″ runat=”server”
ErrorMessage=”Password length must be between 7 to 10 characters”
ControlToValidate=”txtPassword”
ValidationExpression=”^[a-zA-Z]{7,10}$” />
[/xml]

Numeric Only
Minimum length 7 and Maximum length 10. Characters allowed – 0 – 9

[xml]
<asp:RegularExpressionValidator ID=”RegExp1″ runat=”server”
ErrorMessage=”Password length must be between 7 to 10 characters”
ControlToValidate=”txtPassword”
ValidationExpression=”^[0-9]{7,10}$” />
[/xml]

source:
http://www.aspsnippets.com/Articles/ASP.Net-Regular-Expression-Validator-to-validate-Minimum-and-Maximum-Text-Length.aspx