Base Validator Control Sample
The base validator control described here implements the steps described in Developing a Validator Control. The client-side scripting provided by this base validator complies with the World Wide Web Consortium Document Object Model Level 1 specification.
To compile and build this sample, see the instructions in Validator Control Samples. For an overview of client-side scripting in server controls, see Client-Side Functionality in a Server Control.
// BaseDomValidator.cs.
namespace DomValidators {
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Globalization;
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Text.RegularExpressions;
using System.Text;
[
DefaultProperty("ErrorMessage"),
]
public abstract class BaseDomValidator : Label, IValidator {
// Note: these script-enabled controls have two sets
// of client-side script.
// There is a fixed set in a script library called
// DomValidation.js. This goes at the top of the page
// and is put on the page using RegisterClientScriptBlock.
// The second is the dynamic block
// below that contains some inline script that
// should be executed at the end of the page load.
// This is declared using RegisterStartupScript.
private const string ValidatorFileName = "DomValidation.js";
private const string ValidatorIncludeScriptKey = "DomValidatorIncludeScript";
private const string ValidatorStartupScript = @"
<script language=""javascript"">
<!--
var Page_ValidationActive = false;
if (typeof(Page_DomValidationVer) == ""undefined"")
alert(""{0}"");
else
ValidatorOnLoad();
function ValidatorOnSubmit() {{
if (Page_ValidationActive) {{
return ValidatorCommonOnSubmit();
}}
}}
// -->
</script>
";
private const string IncludeScriptFormat = @"
<script language=""{0}"" src=""{1}{2}""></script>";
private bool preRenderCalled;
private bool isValid;
private bool propertiesChecked;
private bool propertiesValid;
private bool renderUplevel;
protected BaseDomValidator() {
isValid = true;
propertiesChecked = false;
propertiesValid = true;
renderUplevel = false;
// Default forecolor for validators is Red.
ForeColor = Color.Red;
}
[
DefaultValue(typeof(Color), "Red")
]
public override Color ForeColor {
get {
return base.ForeColor;
}
set {
base.ForeColor = value;
}
}
[
Category("Behavior"),
DefaultValue(""),
Description("The control to validate."),
TypeConverter(typeof(ValidatedControlConverter))
]
public string ControlToValidate {
get {
object o = ViewState["ControlToValidate"];
return((o == null) ? String.Empty : (string)o);
}
set {
ViewState["ControlToValidate"] = value;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(""),
Description("Error Message")
]
public string ErrorMessage {
get {
object o = ViewState["ErrorMessage"];
return((o == null) ? String.Empty : (string)o);
}
set {
ViewState["ErrorMessage"] = value;
}
}
[
Category("Behavior"),
DefaultValue(true),
Description("Enable Client Script")
]
public bool EnableClientScript {
get {
object o = ViewState["EnableClientScript"];
return((o == null) ? true : (bool)o);
}
set {
ViewState["EnableClientScript"] = value;
}
}
public override bool Enabled {
get {
return base.Enabled;
}
set {
base.Enabled= value;
// When a validator is disabled,
// generally, the intent is not to
// make the page invalid for that round trip.
if (!value) {
isValid = true;
}
}
}
[
Browsable(false),
Category("Behavior"),
DefaultValue(true),
Description("Is Valid"),
DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
]
public bool IsValid {
get {
return isValid;
}
set {
isValid = value;
}
}
protected bool PropertiesValid {
get {
if (!propertiesChecked) {
propertiesValid = ControlPropertiesValid();
propertiesChecked = true;
}
return propertiesValid;
}
}
protected bool RenderUplevel {
get {
return renderUplevel;
}
}
[
Bindable(true),
Category("Appearance"),
DefaultValue(ValidatorDisplay.Static),
Description("Display"),
]
public ValidatorDisplay Display {
get {
object o = ViewState["Display"];
return((o == null) ? ValidatorDisplay.Static : (ValidatorDisplay)o);
}
set {
if (value < ValidatorDisplay.None || value > ValidatorDisplay.Dynamic) {
throw new ArgumentException();
}
ViewState["Display"] = value;
}
}
protected override void AddAttributesToRender(HtmlTextWriter writer) {
// Validators do not render the disabled attribute;
// instead, they are invisible when they are disabled.
bool disabled = !Enabled;
if (disabled) {
Enabled = true;
}
base.AddAttributesToRender(writer);
if (RenderUplevel) {
// A validator must have an ID on the client,
// so if it is null, write it here.
// Otherwise, base.RenderAttributes takes care of it.
if (ID == null) {
writer.AddAttribute("id", ClientID);
}
if (ControlToValidate.Length > 0) {
writer.AddAttribute("controltovalidate", GetControlRenderID(ControlToValidate));
}
if (ErrorMessage.Length > 0) {
writer.AddAttribute("errormessage", ErrorMessage, true);
}
ValidatorDisplay display = Display;
if (display != ValidatorDisplay.Static) {
writer.AddAttribute("display", PropertyConverter.EnumToString(typeof(ValidatorDisplay), display));
}
if (!IsValid) {
writer.AddAttribute("isvalid", "False");
}
if (disabled) {
writer.AddAttribute("enabled", "False");
}
}
if (disabled) {
Enabled = false;
}
}
protected void CheckControlValidationProperty(string name, string propertyName) {
// Get the control using the relative name.
Control c = NamingContainer.FindControl(name);
if (c == null) {
throw new HttpException("Control not found.");
}
// Get the control's validation property.
PropertyDescriptor prop = GetValidationProperty(c);
if (prop == null) {
throw new HttpException("Control cannot be validated.");
}
}
protected virtual bool ControlPropertiesValid() {
// Determine whether the control to validate is blank.
string controlToValidate = ControlToValidate;
if (controlToValidate.Length == 0) {
throw new HttpException("ControlToValidate cannot be blank.");
}
// Check that the property points to a valid control
// (if not, an exception is thrown).
CheckControlValidationProperty(controlToValidate, "ControlToValidate");
return true;
}
protected abstract bool EvaluateIsValid();
protected string GetControlRenderID(string name) {
// Get the control using the relative name.
Control c = FindControl(name);
if (c == null) {
Debug.Fail("We should have already checked for the presence of this");
return "";
}
return c.ClientID;
}
protected string GetControlValidationValue(string name) {
// Get the control using the relative name.
Control c = NamingContainer.FindControl(name);
if (c == null) {
return null;
}
// Get the control's validation property.
PropertyDescriptor prop = GetValidationProperty(c);
if (prop == null) {
return null;
}
// Get its value as a string.
object value = prop.GetValue(c);
if (value is ListItem) {
return((ListItem) value).Value;
}
else if (value != null) {
return value.ToString();
}
else {
return string.Empty;
}
}
public static PropertyDescriptor GetValidationProperty(object component) {
ValidationPropertyAttribute valProp = (ValidationPropertyAttribute)TypeDescriptor.GetAttributes(component)[typeof(ValidationPropertyAttribute)];
if (valProp != null && valProp.Name != null) {
return TypeDescriptor.GetProperties(component, null)[valProp.Name];
}
return null;
}
protected override void OnInit(EventArgs e) {
base.OnInit(e);
Page.Validators.Add(this);
}
protected override void OnUnload(EventArgs e) {
if (Page != null) {
Page.Validators.Remove(this);
}
base.OnUnload(e);
}
protected override void OnPreRender(EventArgs e) {
base.OnPreRender(e);
preRenderCalled = true;
// Force a re-query of properties for render.
propertiesChecked = false;
// Work out uplevelness now.
renderUplevel = DetermineRenderUplevel();
if (renderUplevel) {
RegisterValidatorCommonScript();
}
}
protected virtual bool DetermineRenderUplevel() {
// Must be on a page.
Page page = Page;
if (page == null || page.Request == null) {
return false;
}
// Check the browser capabilities.
// This is how you can get automatic fallback to server-side
// behavior. These validation controls need
// the W3C DOM level 1 for control manipulation
// and need at least ECMAScript 1.2 for the
// regular expressions.
return (EnableClientScript
&& page.Request.Browser.W3CDomVersion.Major >= 1
&& page.Request.Browser.EcmaScriptVersion.CompareTo(new Version(1, 2)) >= 0);
}
protected void RegisterValidatorCommonScript() {
string location = null;
if (!Page.IsClientScriptBlockRegistered(ValidatorIncludeScriptKey)) {
// Provide the location of the script file.
// When using a script library, deployment can be
// a problem because the runtime is
// tied to a specific version of the script file.
// This sample takes the easy way out and insists that
// the file be placed in the /script subdirectory
// of the application.
// In other cases, you should place it where it
// can be shared by multiple applications and is placed
// in a separate directory so that different versions
// of a control library can run side by side.
// The recommended pattern is to put script files in the
// path /aspnet_client/<assembly name>/<assembly version>/".
location = Page.Request.ApplicationPath + "/script/";
// Create the client script block.
string includeScript = String.Format(IncludeScriptFormat, "javascript", location, ValidatorFileName);
Page.RegisterClientScriptBlock(ValidatorIncludeScriptKey, includeScript);
}
if (!Page.IsStartupScriptRegistered(ValidatorIncludeScriptKey)) {
if (location == null) location = Page.Request.ApplicationPath + "/script/";
// Provide an error message, which is localized.
string missingScriptMessage = "Validation script is missing '" + location + ValidatorFileName + "'";
// Create the startup script block.
string startupScript = String.Format(ValidatorStartupScript, new object [] {missingScriptMessage, });
Page.RegisterStartupScript(ValidatorIncludeScriptKey, startupScript);
}
Page.RegisterOnSubmitStatement("ValidatorOnSubmit", "return ValidatorOnSubmit();");
}
protected virtual void RegisterValidatorDeclaration() {
string element = "document.getElementById(\"" + ClientID + "\")";
Page.RegisterArrayDeclaration("Page_Validators", element);
}
protected override void Render(HtmlTextWriter writer) {
bool shouldBeVisible;
if (preRenderCalled == false) {
// This is for design time.
// In this case you do not
// want any expandos or property checks
// and always want the control to be visible
// in the designer.
propertiesChecked = true;
propertiesValid = true;
renderUplevel = false;
shouldBeVisible = true;
}
else {
shouldBeVisible = Enabled && !IsValid;
}
// Do not render if there are errors.
if (!PropertiesValid) {
return;
}
// Specify what to display.
ValidatorDisplay display = Display;
bool displayContents;
bool displayTags;
if (RenderUplevel) {
displayTags = true;
displayContents = (display != ValidatorDisplay.None);
}
else {
displayContents = (display != ValidatorDisplay.None && shouldBeVisible);
displayTags = displayContents;
}
if (displayTags && RenderUplevel) {
// Add this validator to the array
// of validators emitted in the client script.
RegisterValidatorDeclaration();
// Set extra uplevel styles.
if (display == ValidatorDisplay.None
|| (!shouldBeVisible && display == ValidatorDisplay.Dynamic)) {
Style["display"] = "none";
}
else if (!shouldBeVisible) {
Debug.Assert(display == ValidatorDisplay.Static, "Unknown Display Type");
Style["visibility"] = "hidden";
}
}
// Display the contents.
if (displayTags) {
RenderBeginTag(writer);
}
if (displayContents) {
if (Text.Trim().Length > 0) {
RenderContents(writer);
}
else {
writer.Write(ErrorMessage);
}
}
else if (!RenderUplevel && display == ValidatorDisplay.Static) {
// For downlevel browsers in static mode, render a space
// so that table cells do not render as empty.
writer.Write(" ");
}
if (displayTags) {
RenderEndTag(writer);
}
}
public void Validate() {
if (!Visible || !Enabled) {
IsValid = true;
return;
}
// Check whether the container is invisible.
Control parent = Parent;
while (parent != null) {
if (!parent.Visible) {
IsValid = true;
return;
}
parent = parent.Parent;
}
propertiesChecked = false;
if (!PropertiesValid) {
IsValid = true;
return;
}
IsValid = EvaluateIsValid();
}
}
}
[Visual Basic]
' BaseDomValidator.vb.
Option Explicit
Option Strict
Imports System.ComponentModel
Imports System.Diagnostics
Imports System.Drawing
Imports System.Globalization
Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.HtmlControls
Imports System.Text.RegularExpressions
Imports System.Text
Imports Microsoft.VisualBasic
Namespace DomValidators
<DefaultProperty("ErrorMessage")> _
MustInherit Public Class BaseDomValidator
Inherits Label
Implements IValidator
' Note: these script-enabled controls have two sets
' of client-side script.
' There is a fixed set in a script library called
' DomValidation.js. This goes at the top of the page
' and is put on the page using RegisterClientScriptBlock.
' The second is the dynamic block
' below that contains some inline script that
' should be executed at the end of the page load.
' This is declared using RegisterStartupScript.
Private Const ValidatorFileName As String = "DomValidation.js"
Private Const ValidatorIncludeScriptKey As String = "DomValidatorIncludeScript"
Private Const ValidatorStartupScript As String = ControlChars.CrLf & _
"<script language=""javascript"">" & ControlChars.CrLf & _
"<!--" & ControlChars.CrLf & _
"var Page_ValidationActive = false;" & ControlChars.CrLf & _
"if (typeof(Page_DomValidationVer) == ""undefined"")" & ControlChars.CrLf & _
" alert(""{0}"");" & ControlChars.CrLf & _
"else" & ControlChars.CrLf & _
" ValidatorOnLoad();" & ControlChars.CrLf & ControlChars.CrLf & _
"function ValidatorOnSubmit() {{" & ControlChars.CrLf & _
" if (Page_ValidationActive) {{" & ControlChars.CrLf & _
" return ValidatorCommonOnSubmit();" & ControlChars.CrLf & _
" }}" & ControlChars.CrLf & _
"}}" & ControlChars.CrLf & _
"// -->" & ControlChars.CrLf & _
"</script>"
Private Const IncludeScriptFormat As String = ControlChars.CrLf & _
"<script language=""{0}"" src=""{1}{2}""></script>"
Private _preRenderCalled As Boolean
Private _isValid As Boolean
Private _propertiesChecked As Boolean
Private _propertiesValid As Boolean
Private _renderUplevel As Boolean
Protected Sub New()
_isValid = True
_propertiesChecked = False
_propertiesValid = True
_renderUplevel = False
' Default forecolor for validators is Red.
ForeColor = Color.Red
End Sub
<DefaultValue(GetType(Color), "Red")> _
Public Overrides Property ForeColor() As Color
Get
Return MyBase.ForeColor
End Get
Set
MyBase.ForeColor = value
End Set
End Property
<Category("Behavior"), _
DefaultValue(""), _
Description("The control to validate."), _
TypeConverter(GetType(ValidatedControlConverter))> _
Public Property ControlToValidate() As String
Get
Dim o As Object = ViewState("ControlToValidate")
If o Is Nothing Then
Return String.Empty
Else
Return CStr(o)
End If
End Get
Set
ViewState("ControlToValidate") = value
End Set
End Property
<Bindable(True), _
Category("Appearance"), _
DefaultValue(""), _
Description("Error Message")> _
Public Property ErrorMessage() As String Implements IValidator.ErrorMessage
Get
Dim o As Object = ViewState("ErrorMessage")
If o Is Nothing Then
Return String.Empty
Else
Return CStr(o)
End If
End Get
Set
ViewState("ErrorMessage") = value
End Set
End Property
<Category("Behavior"), _
DefaultValue(True), _
Description("Enable Client Script")> _
Public Property EnableClientScript() As Boolean
Get
Dim o As Object = ViewState("EnableClientScript")
If o Is Nothing Then
Return True
Else
Return CBool(o)
End If
End Get
Set
ViewState("EnableClientScript") = value
End Set
End Property
Public Overrides Property Enabled() As Boolean
Get
Return MyBase.Enabled
End Get
Set
MyBase.Enabled = value
' When a validator is disabled,
' generally, the intent is not to
' make the page invalid for that round trip.
If Not value Then
_isValid = True
End If
End Set
End Property
<Browsable(False), _
Category("Behavior"), _
DefaultValue(True), _
Description("Is Valid"), _
DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
Public Property IsValid() As Boolean Implements IValidator.IsValid
Get
Return _isValid
End Get
Set
_isValid = value
End Set
End Property
Protected ReadOnly Property PropertiesValid() As Boolean
Get
If Not _propertiesChecked Then
_propertiesValid = ControlPropertiesValid()
_propertiesChecked = True
End If
Return _propertiesValid
End Get
End Property
Protected ReadOnly Property RenderUplevel() As Boolean
Get
Return _renderUplevel
End Get
End Property
<Bindable(True), _
Category("Appearance"), _
DefaultValue(ValidatorDisplay.Static), _
Description("Display")> _
Public Property Display() As ValidatorDisplay
Get
Dim o As Object = ViewState("Display")
If o Is Nothing Then
Return ValidatorDisplay.Static
Else
Return CType(o, ValidatorDisplay)
End If
End Get
Set
If value < ValidatorDisplay.None Or value > ValidatorDisplay.Dynamic Then
Throw New ArgumentException()
End If
ViewState("Display") = value
End Set
End Property
Protected Overrides Sub AddAttributesToRender(writer As HtmlTextWriter)
' Validators do not render the disabled attribute;
' instead, they are invisible when they are disabled.
Dim disabled As Boolean = Not Me.Enabled
If disabled Then
Me.Enabled = True
End If
MyBase.AddAttributesToRender(writer)
If Me.RenderUplevel Then
' A validator must have an ID on the client,
' so if it is null, write it here.
' Otherwise, base.RenderAttributes takes care of it.
If ID Is Nothing Then
writer.AddAttribute("id", ClientID)
End If
If Me.ControlToValidate.Length > 0 Then
writer.AddAttribute("controltovalidate", Me.GetControlRenderID(ControlToValidate))
End If
If ErrorMessage.Length > 0 Then
writer.AddAttribute("errormessage", Me.ErrorMessage, True)
End If
Dim display As ValidatorDisplay = Me.Display
If display <> ValidatorDisplay.Static Then
writer.AddAttribute("display", PropertyConverter.EnumToString(GetType(ValidatorDisplay), display))
End If
If Not IsValid Then
writer.AddAttribute("isvalid", "False")
End If
If disabled Then
writer.AddAttribute("enabled", "False")
End If
End If
If disabled Then
Enabled = False
End If
End Sub
Protected Sub CheckControlValidationProperty(name As String, propertyName As String)
' Get the control using the relative name.
Dim c As Control = NamingContainer.FindControl(name)
If c Is Nothing Then
Throw New HttpException("Control not found.")
End If
' Get the control's validation property.
Dim prop As PropertyDescriptor = GetValidationProperty(c)
If prop Is Nothing Then
Throw New HttpException("Control cannot be validated.")
End If
End Sub
Protected Overridable Function ControlPropertiesValid() As Boolean
' Determine whether the control to validate is blank.
Dim controlToValidate As String = Me.ControlToValidate
If controlToValidate.Length = 0 Then
Throw New HttpException("ControlToValidate cannot be blank.")
End If
' Check that the property points to a valid
' control (if not, an exception is thrown).
CheckControlValidationProperty(controlToValidate, "ControlToValidate")
Return True
End Function
Protected MustOverride Function EvaluateIsValid() As Boolean
Protected Function GetControlRenderID(name As String) As String
' Get the control using the relative name.
Dim c As Control = FindControl(name)
If c Is Nothing Then
Debug.Fail("We should have already checked for the presence of this")
Return ""
End If
Return c.ClientID
End Function
Protected Function GetControlValidationValue(name As String) As String
' Get the control using the relative name.
Dim c As Control = NamingContainer.FindControl(name)
If c Is Nothing Then
Return Nothing
End If
' Get the control's validation property.
Dim prop As PropertyDescriptor = GetValidationProperty(c)
If prop Is Nothing Then
Return Nothing
End If
' Get the control's value as a string.
Dim value As Object = prop.GetValue(c)
If TypeOf value Is ListItem Then
Return CType(value, ListItem).Value
Else
If Not (value Is Nothing) Then
Return value.ToString()
Else
Return String.Empty
End If
End If
End Function
Public Shared Function GetValidationProperty(component As Object) As PropertyDescriptor
Dim valProp As ValidationPropertyAttribute = CType(TypeDescriptor.GetAttributes(component)(GetType(ValidationPropertyAttribute)), ValidationPropertyAttribute)
If Not (valProp Is Nothing) And Not (valProp.Name Is Nothing) Then
Return TypeDescriptor.GetProperties(component)(valProp.Name)
End If
Return Nothing
End Function
Protected Overrides Sub OnInit(e As EventArgs)
MyBase.OnInit(e)
Page.Validators.Add(Me)
End Sub
Protected Overrides Sub OnUnload(e As EventArgs)
If Not (Page Is Nothing) Then
Page.Validators.Remove(Me)
End If
MyBase.OnUnload(e)
End Sub
Protected Overrides Sub OnPreRender(e As EventArgs)
MyBase.OnPreRender(e)
_preRenderCalled = True
' Force a re-query of properties for render.
_propertiesChecked = False
' Work out uplevelness now.
_renderUplevel = DetermineRenderUplevel()
If _renderUplevel Then
RegisterValidatorCommonScript()
End If
End Sub
Protected Overridable Function DetermineRenderUplevel() As Boolean
' Must be on a page.
Dim page As Page = Page
If page Is Nothing OrElse page.Request Is Nothing Then
Return False
End If
' Check the browser capabilities.
' This is how you can get automatic fallback to server-side
' behavior. These validation controls need
' the W3C DOM level 1 for control manipulation
' and need at least ECMAScript 1.2 for the
' regular expressions.
Return EnableClientScript AndAlso _
page.Request.Browser.W3CDomVersion.Major >= 1 AndAlso _
page.Request.Browser.EcmaScriptVersion.CompareTo(New Version(1, 2)) >= 0
End Function
Protected Sub RegisterValidatorCommonScript()
Dim location As String = Nothing
If Not Page.IsClientScriptBlockRegistered(ValidatorIncludeScriptKey) Then
' Provide the location of the script file.
' When using a script library, deployment can be
' a problem because the runtime is
' tied to a specific version of the script file.
' This sample takes the easy way out and insists that
' the file be placed in the /script subdirectory
' of the application.
' In other cases, you should place it where it
' can be shared by multiple applications and is placed
' in a separate directory so that different versions
' of a control library can run side by side.
' The recommended pattern is to put script files in the
' path /aspnet_client/<assembly name>/<assembly version>/".
location = Page.Request.ApplicationPath & "/script/"
' Create the client script block.
Dim includeScript As String = String.Format(IncludeScriptFormat, "javascript", location, ValidatorFileName)
Page.RegisterClientScriptBlock(ValidatorIncludeScriptKey, includeScript)
End If
If Not Page.IsStartupScriptRegistered(ValidatorIncludeScriptKey) Then
If location Is Nothing Then
location = Page.Request.ApplicationPath & "/script/"
End If
' Provide an error message, which is localized.
Dim missingScriptMessage As String = "Validation script is missing '" & location & ValidatorFileName & "'"
' Create the startup script block.
Dim startupScript As String = String.Format(ValidatorStartupScript, New Object() {missingScriptMessage})
Page.RegisterStartupScript(ValidatorIncludeScriptKey, startupScript)
End If
Page.RegisterOnSubmitStatement("ValidatorOnSubmit", "return ValidatorOnSubmit();")
End Sub
Protected Overridable Sub RegisterValidatorDeclaration()
Dim element As String = "document.getElementById(""" & ClientID & """)"
Page.RegisterArrayDeclaration("Page_Validators", element)
End Sub
Protected Overrides Sub Render(writer As HtmlTextWriter)
Dim shouldBeVisible As Boolean
If _preRenderCalled = False Then
' This is for design time.
' In this case you do not
' want any expandos or property checks
' and always want the control to be visible in the designer.
_propertiesChecked = True
_propertiesValid = True
_renderUplevel = False
shouldBeVisible = True
Else
shouldBeVisible = Enabled And Not IsValid
End If
' Do not render if there are errors.
If Not PropertiesValid Then
Return
End If
' Specify what to display.
Dim display As ValidatorDisplay = Me.Display
Dim displayContents As Boolean
Dim displayTags As Boolean
If RenderUplevel Then
displayTags = True
displayContents = display <> ValidatorDisplay.None
Else
displayContents = display <> ValidatorDisplay.None And shouldBeVisible
displayTags = displayContents
End If
If displayTags And RenderUplevel Then
' Add this validator to the array
' of validators emitted in the client script.
RegisterValidatorDeclaration()
' Set extra uplevel styles.
If display = ValidatorDisplay.None Or(Not shouldBeVisible And display = ValidatorDisplay.Dynamic) Then
Style("display") = "none"
Else
If Not shouldBeVisible Then
Debug.Assert(display = ValidatorDisplay.Static, "Unknown Display Type")
Style("visibility") = "hidden"
End If
End If
End If
' Display the contents.
If displayTags Then
RenderBeginTag(writer)
End If
If displayContents Then
If Text.Trim().Length > 0 Then
RenderContents(writer)
Else
writer.Write(ErrorMessage)
End If
Else
If Not RenderUplevel And display = ValidatorDisplay.Static Then
' For downlevel browsers in static mode, render a space so
' that table cells do not render as empty.
writer.Write(" ")
End If
End If
If displayTags Then
RenderEndTag(writer)
End If
End Sub
Public Sub Validate() Implements IValidator.Validate
If Not Visible Or Not Enabled Then
IsValid = True
Return
End If
' Check whether the container is invisible.
Dim parent As Control = Parent
While Not (parent Is Nothing)
If Not parent.Visible Then
IsValid = True
Return
End If
parent = parent.Parent
End While
_propertiesChecked = False
If Not PropertiesValid Then
IsValid = True
Return
End If
IsValid = EvaluateIsValid()
End Sub
End Class
End Namespace
See Also
Validator Control Samples | Required Field Validator Control Sample | Regular Expression Validator Control Sample | Script Library for Validator Sample | Configuration File for Validator Sample | Test Page for Validator Sample | Developing a Validator Control