A Validation server control is used to validate the data of an input control. If the data does not pass validation, it will display an error message to the user.
The syntax for creating a Validation server control is:
| <asp:control_name id="some_id" runat="server" /> |
| Validation Server Control | Description |
|---|---|
| CompareValidator | Compares the value of one input control to the value of another input control or to a fixed value |
| CustomValidator | Allows you to write a method to handle the validation of the value entered |
| RangeValidator | Checks that the user enters a value that falls between two values |
| RegularExpressionValidator | Ensures that the value of an input control matches a specified pattern |
| RequiredFieldValidator | Makes an input control a required field |
| ValidationSummary | Displays a report of all validation errors occurred in a Web page |
ASP.NET Compare Validator Control
Definition and Usage
The CompareValidator control is used to compare the value of one input control to the value of another input control or to a fixed value.
Note: If the input control is empty, the validation will succeed. Use the RequiredFieldValidator control to make the field required.
Properties
| Property | Description |
|---|---|
| BackColor | The background color of the CompareValidator control |
| ControlToCompare | The name of the control to compare with |
| ControlToValidate | The id of the control to validate |
| Display | The display behavior for the validation control. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ErrorMessage | The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set |
| ForeColor | The foreground color of the control |
| id | A unique id for the control |
| IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
| Operator | The type of comparison to perform. The operators are:
|
| runat | Specifies that the control is a server control. Must be set to "server" |
| Text | The message to display when validation fails |
| Type | Specifies the data type of the values to compare. The types are:
|
| ValueToCompare | A specified value to compare with |
ASP.NET CustomValidator Control
Definition and Usage
The CustomValidator control allows you to write a method to handle the validation of the value entered.
Properties
Property Description BackColor The background color of the CustomValidator control ClientValidationFunction Specifies the name of the client-side validation script function to be executed. Note: The script must be in a language that the browser supports, such as VBScript or JScript
With VBScript, the function must be in the form:Sub FunctionName (source, arguments)With JScript, the function must be in the form:Function FunctionName (source, arguments) ControlToValidate The id of the control to validate Display The display behavior for the validation control. Legal values are:
- None (the control is not displayed. Used to show the error message only in the ValidationSummary control)
- Static (the control displays an error message if validation fails. Space is reserved on the page for the message even if the input passes validation.
- Dynamic (the control displays an error message if validation fails. Space is not reserved on the page for the message if the input passes validation
EnableClientScript A Boolean value that specifies whether client-side validation is enabled or not Enabled A Boolean value that specifies whether the validation control is enabled or not ErrorMessage The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set ForeColor The foreground color of the control id A unique id for the control IsValid A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid OnServerValidate Specifies the name of the server-side validation script function to be executed runat Specifies that the control is a server control. Must be set to "server" Text The message to display when validation fails
<script runat="server">Definition and Usage
The CustomValidator control allows you to write a method to handle the validation of the value entered.
Properties
| Property | Description |
|---|---|
| BackColor | The background color of the CustomValidator control |
| ClientValidationFunction | Specifies the name of the client-side validation script function to be executed. Note: The script must be in a language that the browser supports, such as VBScript or JScript With VBScript, the function must be in the form: Sub FunctionName (source, arguments) With JScript, the function must be in the form: Function FunctionName (source, arguments) |
| ControlToValidate | The id of the control to validate |
| Display | The display behavior for the validation control. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ErrorMessage | The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set |
| ForeColor | The foreground color of the control |
| id | A unique id for the control |
| IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
| OnServerValidate | Specifies the name of the server-side validation script function to be executed |
| runat | Specifies that the control is a server control. Must be set to "server" |
| Text | The message to display when validation fails |
Sub user(source As object,args As ServerValidateEventArgs)
if len(args.Value)<8 or len(args.Value)>16 then
args.IsValid=false
else
args.IsValid=true
end if
End Sub
</script>
<html>
<body>
<form runat="server">
<asp:Label runat="server" Text="Enter a username: " />
<asp:TextBox id="txt1" runat="server" />
<asp:Button Text="Submit" runat="server"/>
<br />
<asp:Label id="mess" runat="server"/>
<br />
<asp:CustomValidator
ControlToValidate="txt1"
OnServerValidate="user"
Text="A username must be between 8 and 16 characters!"
runat="server"/>
</form>
</body>
</html>
ASP.NET RangeValidator Control
Definition and Usage
The RangeValidator control is used to check that the user enters an input value that falls between two values. It is possible to check ranges within numbers, dates, and characters.
Note: The validation will not fail if the input control is empty. Use the RequiredFieldValidator control to make the field required.
Note: The validation will not fail if the input value cannot be converted to the data type specified. Use the CompareValidator control, with its Operator property set to ValidationCompareOperator.DataTypeCheck, to verify the data type of the input value.
Properties
| Property | Description |
|---|---|
| BackColor | The background color of the RangeValidator control |
| ControlToValidate | The id of the control to validate |
| Display | The display behavior for the validation control. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ErrorMessage | The text to display in the ValidationSummary control when validation fails.Note: This text will also be displayed in the validation control if the Text property is not set |
| ForeColor | The foreground color of the control |
| id | A unique id for the control |
| IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
| MaximumValue | Specifies the maximum value of the input control |
| MinimumValue | Specifies the minimum value of the input control |
| runat | Specifies that the control is a server control. Must be set to "server" |
| Type | Specifies the data type of the value to check. The types are:
|
| Text | The message to display when validation fails |
Examples
<html>
<body>
<form runat="server">
Enter a date between 2005-01-01 and 2005-12-31:
<br />
<asp:TextBox id="tbox1" runat="server" />
<br /><br />
<asp:Button Text="Submit" runat="server" />
<br /><br />
<asp:RangeValidator
ControlToValidate="tbox1"
MinimumValue="2005-01-01"
MaximumValue="2005-12-31"
Type="Date"
EnableClientScript="false"
Text="The date must be between 2005-01-01 and 2005-12-31!"
runat="server" />
</form>
</body>
</html>
<body>
<form runat="server">
Enter a date between 2005-01-01 and 2005-12-31:
<br />
<asp:TextBox id="tbox1" runat="server" />
<br /><br />
<asp:Button Text="Submit" runat="server" />
<br /><br />
<asp:RangeValidator
ControlToValidate="tbox1"
MinimumValue="2005-01-01"
MaximumValue="2005-12-31"
Type="Date"
EnableClientScript="false"
Text="The date must be between 2005-01-01 and 2005-12-31!"
runat="server" />
</form>
</body>
</html>
ASP.NET RegularExpressionValidator Control
The RegularExpressionValidator control is used to ensure that an input value matches a specified pattern.
Note: Both server- and client-side validation are performed unless the browser does not support client-side validation or the EnableClientScript property is set to false.
Note: The validation will not fail if the input control is empty. Use the RequiredFieldValidator control to make the field required.
Properties
| Property | Description |
|---|---|
| BackColor | The background color of the RegularExpressionValidator control |
| ControlToValidate | The id of the control to validate |
| Display | The display behavior for the validation control. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ErrorMessage | The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set |
| ForeColor | The foreground color of the control |
| id | A unique id for the control |
| IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
| runat | Specifies that the control is a server control. Must be set to "server" |
| BackColor | The background color of the RegularExpressionValidator control |
| Text | The message to display when validation fails |
| ValidationExpression | Specifies the expression used to validate input control. The expression validation syntax is different on the client than on the server. JScript is used on the client. On the server, the language you have specified is used |
Example
<script runat="server">
sub submit(sender As Object, e As EventArgs)
if Page.IsValid then
lbl.Text="The page is valid!"
else
lbl.Text="The page is not valid!"
end if
end sub
</script>
<html>
<body>
<form runat="server">
Enter a US zip code:
<asp:TextBox id="txtbox1" runat="server" />
<br /><br />
<asp:Button text="Submit" OnClick="submit" runat="server" />
<br /><br />
<asp:Label id="lbl" runat="server" />
<br />
<asp:RegularExpressionValidator
ControlToValidate="txtbox1"
ValidationExpression="\d{5}"
EnableClientScript="false"
ErrorMessage="The zip code must be 5 numeric digits!"
runat="server" />
</form>
</body>
</html>
sub submit(sender As Object, e As EventArgs)
if Page.IsValid then
lbl.Text="The page is valid!"
else
lbl.Text="The page is not valid!"
end if
end sub
</script>
<html>
<body>
<form runat="server">
Enter a US zip code:
<asp:TextBox id="txtbox1" runat="server" />
<br /><br />
<asp:Button text="Submit" OnClick="submit" runat="server" />
<br /><br />
<asp:Label id="lbl" runat="server" />
<br />
<asp:RegularExpressionValidator
ControlToValidate="txtbox1"
ValidationExpression="\d{5}"
EnableClientScript="false"
ErrorMessage="The zip code must be 5 numeric digits!"
runat="server" />
</form>
</body>
</html>
ASP.NET RequiredFieldValidator Control
Definition and Usage
The RequiredFieldValidator control is used to make an input control a required field.
With this control, the validation fails if the input value does not change from its initial value. By default, the initial value is an empty string ("").
Note: Leading and trailing spaces of the input value are removed before validation.
Note: The InitialValue property does not set the default value for the input control. It indicates the value that you do not want the user to enter in the input control.
Properties
| Property | Description |
|---|---|
| BackColor | The background color of the RequiredFieldValidator control |
| ControlToValidate | The id of the control to validate |
| Display | The display behavior for the validation control. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ErrorMessage | The text to display in the ValidationSummary control when validation fails. Note: This text will also be displayed in the validation control if the Text property is not set |
| ForeColor | The foreground color of the control |
| id | A unique id for the control |
| InitialValue | Specifies the starting value of the input control. Default value is "" |
| IsValid | A Boolean value that indicates whether the control specified by ControlToValidate is determined to be valid |
| runat | Specifies that the control is a server control. Must be set to "server" |
| Text | The message to display when validation fails |
Example
<html>
<body>
<form runat="server">
Name: <asp:TextBox id="name" runat="server" />
<br />
Age: <asp:TextBox id="age" runat="server" />
<br /><br />
<asp:Button runat="server" Text="Submit" />
<br /><br />
<asp:RequiredFieldValidator
ControlToValidate="name"
Text="The name field is required!"
runat="server" />
</form>
</body>
</html>
<body>
<form runat="server">
Name: <asp:TextBox id="name" runat="server" />
<br />
Age: <asp:TextBox id="age" runat="server" />
<br /><br />
<asp:Button runat="server" Text="Submit" />
<br /><br />
<asp:RequiredFieldValidator
ControlToValidate="name"
Text="The name field is required!"
runat="server" />
</form>
</body>
</html>
ASP.NET ValidationSummary Control
Definition and Usage
The ValidationSummary control is used to display a summary of all validation errors occurred in a Web page.
The error message displayed in this control is specified by the ErrorMessage property of each validation control. If the ErrorMessage property of the validation control is not set, no error message is displayed for that validation control.
Properties
| Property | Description |
|---|---|
| DisplayMode | How to display the summary. Legal values are:
|
| EnableClientScript | A Boolean value that specifies whether client-side validation is enabled or not |
| Enabled | A Boolean value that specifies whether the validation control is enabled or not |
| ForeColor | The fore color of the control |
| HeaderText | A header in the ValidationSummary control |
| id | A unique id for the control |
| runat | Specifies that the control is a server control. Must be set to "server" |
| ShowMessageBox | A Boolean value that specifies whether the summary should be displayed in a message box or not |
| ShowSummary | A Boolean value that specifies whether the ValidationSummary control should be displayed or hidden |
Examples
<html>
<body>
<form runat="server">
<table>
<tr>
<td>
<table bgcolor="#b0c4de" cellspacing="10">
<tr>
<td align="right">Name:</td>
<td><asp:TextBox id="txt_name" runat="server"/></td>
<td>
<asp:RequiredFieldValidator
ControlToValidate="txt_name"
ErrorMessage="Name"
Text="*"
runat="server"/>
</td>
</tr>
<tr>
<td align="right">Card Type:</td>
<td>
<asp:RadioButtonList id="rlist_type"
RepeatLayout="Flow"
runat="server">
<asp:ListItem>Diners</asp:ListItem>
<asp:ListItem>MasterCard</asp:ListItem>
<asp:ListItem>Visa</asp:ListItem>
</asp:RadioButtonList>
</td>
<td>
<asp:RequiredFieldValidator
ControlToValidate="rlist_type"
ErrorMessage="Card Type"
InitialValue=""
Text="*"
runat="server"/>
</td>
</tr>
<tr>
<td></td>
<td><asp:Button id="b1" Text="Submit" runat="server"/></td>
<td></td>
</tr>
</table>
</td>
</tr>
</table>
<br />
<asp:ValidationSummary
HeaderText="You must enter a value in the following fields:"
DisplayMode="BulletList"
EnableClientScript="true"
runat="server"/>
</form>
</body>
</html>
<body>
<form runat="server">
<table>
<tr>
<td>
<table bgcolor="#b0c4de" cellspacing="10">
<tr>
<td align="right">Name:</td>
<td><asp:TextBox id="txt_name" runat="server"/></td>
<td>
<asp:RequiredFieldValidator
ControlToValidate="txt_name"
ErrorMessage="Name"
Text="*"
runat="server"/>
</td>
</tr>
<tr>
<td align="right">Card Type:</td>
<td>
<asp:RadioButtonList id="rlist_type"
RepeatLayout="Flow"
runat="server">
<asp:ListItem>Diners</asp:ListItem>
<asp:ListItem>MasterCard</asp:ListItem>
<asp:ListItem>Visa</asp:ListItem>
</asp:RadioButtonList>
</td>
<td>
<asp:RequiredFieldValidator
ControlToValidate="rlist_type"
ErrorMessage="Card Type"
InitialValue=""
Text="*"
runat="server"/>
</td>
</tr>
<tr>
<td></td>
<td><asp:Button id="b1" Text="Submit" runat="server"/></td>
<td></td>
</tr>
</table>
</td>
</tr>
</table>
<br />
<asp:ValidationSummary
HeaderText="You must enter a value in the following fields:"
DisplayMode="BulletList"
EnableClientScript="true"
runat="server"/>
</form>
</body>
</html>
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