C#: RegularExpressionValidator control

It is used to validate the user input based on the validation expression.

Meta characters used to prepare the expression for single digit

\d	Accepts a single digit
/D	Accepts a single character
\w	Accepts any character other than a white space (spacebar)
\s	Accepts a space
[A-Za-z]	Accepts upper or lower case characters
[0-9]	Accepts a numerical value
^[0-9]	Accepts any characters other than numeric value

Occurrences:

It is used to specify the occurrence of the meta characters within the expression.

{number}	Accepts the input if the length of the expression is equal to the specified number E.g.: \d{5} à accepts 5 digits number
{Minnumber, }	Accepts the input if the length after expression is greater than or equal to the specified Minnumber. E.g: [A-Za-z0-9_]{6, }
{Minnumber, Maxnumber}	Accepts the input if the length of the expression is between the specified range. e.g.: \D{6,8}

Modes:

It is used to specify the occurrence of the meta characters within the expression.

.ASPX CODE

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server"

ControlToValidate="TextBox1" ErrorMessage="plese enter email ID"

ToolTip="plese Enter email id" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator>

Output:

C#