| Hi, You can write a regular _expression_ as shown in the example below: ' RegexDomValidator.vb
Option Explicit
Option Strict Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Diagnostics
Imports System.Text.RegularExpressions
Imports System.Drawing.Design
Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace DomValidators
<ToolboxData("<{0}:RegexDomValidator runat=server ErrorMessage=""RegexDomValidator""></{0}:RegexDomValidator>")> _
Public Class RegexDomValidator
Inherits BaseDomValidator
<Bindable(True), _
Category("Behavior"), _
DefaultValue(""), _
Editor("System.Web.UI.Design.WebControls.RegexTypeEditor,System.Design", _
GetType(UITypeEditor)), _
Description("ValidationExpression")> _
Public Property ValidationExpression() As String
Get
Dim o As Object = ViewState("ValidationExpression")
If o Is Nothing Then
Return String.Empty
Else
Return CStr(o)
End If
End Get
Set
Try
Regex.IsMatch("", value)
Catch e As Exception
'Throw new HttpException.
' HttpRuntime.FormatResourceString(SR.Validator_bad_regex, value), e);
Throw New HttpException("Bad _expression_", e)
End Try
ViewState("ValidationExpression") = value
End Set
End Property
Protected Overrides Sub AddAttributesToRender(writer As HtmlTextWriter)
MyBase.AddAttributesToRender(writer)
If RenderUplevel Then
writer.AddAttribute("evaluationfunction", "RegularExpressionValidatorEvaluateIsValid")
If ValidationExpression.Length > 0 Then
writer.AddAttribute("validationexpression", ValidationExpression)
End If
End If
End Sub
Protected Overrides Function EvaluateIsValid() As Boolean
' Always succeeds if input is empty or value was not found.
Dim controlValue As String = GetControlValidationValue(ControlToValidate)
Debug.Assert( Not (controlValue Is Nothing), "Should have already been checked")
If controlValue Is Nothing Or controlValue.Length = 0 Then
Return True
End If
Try
' Looking for an exact match, not just a search hit.
Dim m As Match = Regex.Match(controlValue, ValidationExpression)
Return m.Success And m.Index = 0 And m.Length = controlValue.Length
Catch
End Try
End Function
End Class
End Namespace
In the validator _expression_, you can check for the dd/mm/yyyy format as , the value in the textbox is compared with the value of the validator _expression_. In the above code, the validator _expression_ checks for empty and null spaces. you can code it to check for date value. HTH Regards Lakshmi |
