May 30

Written by: Steve Gray
5/30/2010 3:12 PM 

Here is quick start example to code to demonstrate two principles in the Validation Application Block.

We’re going to show how validation works in a class, and on an ASP.NET page.

The concept is that you create a class that represents a data object (we’re using ‘customer’ here) and decorate the class with data validators. We’re only showing a ‘StringLengthValidator’, but if you get that working you’ll easily be able to look up the other types.

Download and install the Enterprise Library 5.0 objects

Create a web project, and set a reference to these dlls:

• Microsoft.Practices.EnterpriseLibrary.Validation.dll
• Microsoft.Practices.EnterpriseLibrary.Common.dll
• Microsoft.Practices.ServiceLocation.dll
• Microsoft.Practices.Unity.dll
• Microsoft.Practices.Unity.Interception.dll

Add this code to your web site – you’ll need default.aspx and a class called ‘Customer’

First the ASP.NET page:

<%@ Page Title="Home Page" Language="VB" MasterPageFile="~/Site.Master" AutoEventWireup="false"
    CodeFile="Default.aspx.vb" Inherits="_Default" %>
    <%@ Register Assembly="Microsoft.Practices.EnterpriseLibrary.Validation.Integration.AspNet"
             Namespace="Microsoft.Practices.EnterpriseLibrary.Validation.Integration.AspNet"
             TagPrefix="cc1" %> 
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:Label ID="lblError" runat="server" ForeColor="Red"></asp:Label>
    <table>
        <tr>
            <td>Customer Name</td>
            <td>
                <asp:TextBox ID="txtCustname" runat="server" MaxLength="65" Text="a"></asp:TextBox>
                <cc1:propertyproxyvalidator 
                    id="Propertyproxyvalidator1" 
                    runat="server" 
                    sourcetypename="Customer"
                    propertyname="custname" 
                    controltovalidate="txtCustname" 
                    ForeColor="Red" 
                    EnableClientScript="true" ></cc1:propertyproxyvalidator>
            </td>
        </tr>
        <tr>
            <td>Customer Number</td>
            <td>
                <asp:TextBox ID="txtCustnmbr" runat="server" MaxLength="15" Text="b"></asp:TextBox>
                <cc1:propertyproxyvalidator 
                    id="CustnmbrValidator" 
                    runat="server" 
                    sourcetypename="Customer"
                    propertyname="custnmbr" 
                    controltovalidate="txtCustnmbr" 
                    ForeColor="Red" 
                    OnValueConvert="CustnmbrValidator_ValueConvert"></cc1:propertyproxyvalidator>
            </td>
        </tr>
        <tr>
            <td colspan="2">
                <asp:Button ID="btnSubmit" runat="server" Text="Submit" />
            </td>
        </tr>
    </table>
</asp:Content>

 

Here’s the code behind:

Imports Microsoft.Practices.EnterpriseLibrary.Validation
Imports Microsoft.Practices.EnterpriseLibrary.Validation.Integration
Partial Class _Default
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Me.lblError.Text = ""
        Me.lblError.ForeColor = Drawing.Color.Red
    End Sub
    Protected Sub CustnmbrValidator_ValueConvert(ByVal sender As Object, ByVal e As ValueConvertEventArgs) Handles CustnmbrValidator.ValueConvert
        'this executes before the btnSubmit code, and only affects the 'validated value' for the 
        'textbox itself
        'this value is not stored in the textbox, and the btnSubmit code doesn't see it
        e.ConvertedValue = "cccc"
    End Sub
    Protected Sub btnSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
        Try
            If IsValid Then
                Dim oCust As New Customer
                Dim strError As String = ""
                'above, custnmbr was converted. But here, we only see the actual value in the text box. 
                oCust.custnmbr = Me.txtCustnmbr.Text
                oCust.custname = Me.txtCustname.Text
                Dim myValidator As Microsoft.Practices.EnterpriseLibrary.Validation.Validator = ValidationFactory.CreateValidator(Of Customer)()
                Dim myResults As New ValidationResults()
                myValidator.Validate(oCust, myResults)
                If Not myResults.IsValid Then
                    strError = "Error:<br/>"
                    For Each vr As ValidationResult In myResults
                        strError += vr.Message & "<br/>"
                    Next
                    Throw New Exception(strError)
                End If
                Me.lblError.Text = "Successful Validation"
                Me.lblError.ForeColor = System.Drawing.Color.ForestGreen
            End If
        Catch ex As Exception
            Me.lblError.Text = ex.Message
        End Try
    End Sub
End Class

 

And finally the class:

Imports Microsoft.VisualBasic
Imports Microsoft.Practices.EnterpriseLibrary.Validation
Imports Microsoft.Practices.EnterpriseLibrary.Validation.Validators
Public Class Customer
    <StringLengthValidator(3, 10, MessageTemplate:="The customer name must be between 3 and 10 characters")> _
    Public Property custname As String
    <StringLengthValidator(4, 10, MessageTemplate:="The customer number must be between 4 and 10 characters")> _
    Public Property custnmbr As String
End Class