RegularExpressionValidator has two main attributes for validity verification. ControlToValidate contains a value for verification. Take out the value in the text box. For example, ControlToValidate = "TextBox1" ValidationExpression contains a regular expression for verification.
Well, with the above description, we will give an example to illustrate the regular expression. For example, if we want to verify the email entered by the user, what kind of data is a legal email? I can enter: test @ like this, of course I will also enter: xxx@yyy.com.cn, but such input is illegal: xxx @ com.cn or @ xxx.com.cn, and so on, therefore, a valid email address must meet at least the following conditions:
1. It must contain one and only one symbol "@".
2. The first character cannot be "@" or "."
3. "@." or ". @" cannot appear .@
4. The end cannot be the character "@" or "."
Therefore, based on the above principles and the syntax in the above table, we can easily obtain the required template as follows: "=" ^ w + (-w +) | (. w +) * @ [A-Za-z0-9] + ((. |-) [A-Za-z0-9] + )*. [A-Za-z0-9] + $"
See the content of validata6.aspx:
<! -- Source File: formweb page description validate6.aspx -->
</Head>
<Body>
<Center> <P>
<Form runat = "server">
<Center>
<Title> Regular expression verification </title>
<Table bgcolor = "# eeeeee" cellpadding = 10>
<Tr valign = "top">
<Td colspan = 3>
<Asp: Label ID = "lblOutput" Text = "Enter the email address" Font-Name = "Verdana" Font-Size = "10pt" runat = "server"/>
</Td>
</Tr>
<Tr>
<Td align = right>
<Font face = Verdana size = 2> E-mail: </font>
