June 4, 2011 06:23 by
ScottThis article is continuation of ASP.NET AJAX 4.0 Template Programming Part 1. In this part, I explain the different data binding options in ASP.NET AJAX 4.0 templates. Just a recap that I've consumed an ADO.NET data services to fetch AdventureWorks's Product table records. In this article, I explain how to update/add new record from client side.
Bindings
Template supports the following bindings:
- One-time - The expression is evaluated only once when the template rendering happen
- One-way Live Binding - The expression is evaluated and update the value, if items in the data source changed
- Two-way Live Binding - If the data source value changed, the value in the expression updated. And if the value in the expression is updated, it will update data source also.
The below diagram depicts the binding.
In the above diagram, the red dashed arrow shows one-time data binding. Once the data from data source has been fetched by DataView using AdoNetDataContext. The one-way live binding has been shown as purple shadowed arrow. The purpose shadow here is whenever a data updated at data source, it is being updated to data view through AdoNetDataContext. The two-way live binding has been shown as green shadowed two-head arrow. In this case, data context should have the knowledge about update operation on data source and provide an interface to data view to send the modified values.
The these three bindings, ASP.NET AJAX provides the following expression convention:
- {{ }} - One-time (can be used on any HTML controls for example <p>{{ Name }}</p>)
- { binding } - One-way if other than user input HTML controls for example <td>{ binding Name } </td>
- {binding } - Two-way if INPUT HTML controls for example <input type="text" sys:value="{{ binding Name }}" />
Here, the input controls binds the values using sys:value attribute for two-way binding. Before going into the updatable data source, let us see how can we design master-detail layout to display Product name and Product details.
Master-Detail Layout
<body xmlns:sys="javascript:Sys"
xmlns:dataview="javascript:Sys.UI.DataView"
sys:activate="*">
<form id="form1" runat="server">
<div>
<!--Master View-->
<ul sys:attach="dataview" class=" sys-template"
dataview:autofetch="true"
dataview:dataprovider="{{ dataContext }}"
dataview:fetchoperation="Products"
dataview:selecteditemclass="myselected"
dataview:fetchparameters="{{ {$top:'5'} }}"
dataview:sys-key="master"
>
<li sys:command="Select">{binding Name }</li>
</ul>
<!--Detail View-->
<div class="sys-template"
sys:attach="dataview"
dataview:autofetch="true"
dataview:data="{binding selectedData, source={{master}} }">
<fieldset>
<legend>{binding Name}</legend>
<label for="detailsListPrice">List Price:</label>
<input type="text" id="detailsListPrice"
sys:value="{binding ListPrice}" />
<br />
<label for="detailsWeight">Weight:</label>
<input type="text" id="detailsWeight" sys:value="{binding Weight}" />
<br />
</fieldset>
<button onclick="dataContext.saveChanges()">Save Changes</button>
</div>
</div>
</form>
</body>
Selectable And Editable
An unordered list shows the master details, here the product name (line 15). This line also indicates that the list item is selectable using sys:command="Select". For maintaining master-detail or selectable item, primary key needs to be specified. The sys-key property of data view refers that primary key. In this example, I call the primary key as "master" (line 13). Also, you can see that I've passed a filter option using fetchparameter property of data view (line 12). In this example, I request the ADO.NET data service to give only top five records using its filter syntax.
Whenever an item in the master list is selected, the details view needs to be notified. The widget for the details view and binding details should be identified using regular sys:attach="dataview" and dataview's data property. In this example, dataview:data="{binding selectedData, source={{master}} }" specifies that binding with data view with sys-key name "master". The fieldset is used to show set of values for a product. Here, the list price and weight can be editable.
Once an item has been edited, this needs to be notified to the data source through data context. The button with caption "Save Changes" specifies that whenver this button is clicked, save the items in the details view into data source through data context's saveChanges() method. The corresponding data source's update option should be set on data context's set_saveOperation(). The following JavaScript code explains this.
var dataContext = new Sys.Data.AdoNetDataContext();
dataContext.set_serviceUri("AWProductDataService.svc");
dataContext.set_saveOperation("Products(master)");
dataContext.initialize();
The ADO.NET Product data service's Products(id) method is used on set_saveOperation. An item can be updated, when Product service of ADO.NET data service is being invoked with product primary key as argument. Here, again I'm referring master layout's "master" sys-key as primary key of Product.
The output of the above code is
The top one is master view where Sport-100 Helmet, Red is selected and the details has been shown in the bottom page. You can edit and update the data source.
The selecteditemclass property of data view is used to show the selected item in different style.
.myselected {
color: white;
font-weight: bold;
background-color: Silver;
}
May 13, 2011 07:26 by
ScottFor those of you who just upgraded your site to the latest ASP.NET 4.0 Framework, you may sometimes see this error message: “A potentially dangerous Request.QueryString value was detected from the client”.
The request validation feature in ASP.NET provides a certain level of default protection against cross-site scripting (XSS) attacks. In previous versions of ASP.NET, request validation was enabled by default. However, it applied only to ASP.NET and only when those pages were executing.
In ASP.NET 4, by default, request validation is enabled for all requests, because it is enabled before the BeginRequest phase of an HTTP request. As a result, request validation applies to requests for all ASP.NET resources, not just .aspx page requests. This includes requests such as Web service calls and custom HTTP handlers. Request validation is also active when custom HTTP modules are reading the contents of an HTTP request.
As a result, request validation errors might now occur for requests that previously did not trigger errors. To revert to the behavior of the ASP.NET 2.0 request validation feature, add the following setting in the Web.Config file:
<httpRuntime requestValidationMode="2.0" />
However, we recommend that you analyze any request validation errors to determine whether existing handlers, modules, or other custom code accesses potentially unsafe HTTP inputs that could be XSS attack vectors.
If you have problem with this upgrade, you can host your site with us. We are the premier European hosting that support ASP.NET 4 hosting with only €3.00/month. If you don’t like our service, you can just cancel your account.
May 10, 2011 06:10 by
ScottBy default the client-side validation is triggered when submitting forms using buttons. However, sometimes you may want to trigger client-side validation on your ASP page manually from custom Javascript. You can achieve that by calling Javascript validation functions provided by the ASP.Net framework directly from your custom code.
The following page source example displays a TextBox and its validation controls (RequiredFieldValidator & ValidationSummary). The validation controls have the same ValidationGroup defined, which allows us to validate different page elements independently. The page displays also a DIV element that will cause the Validation action when clicked:
<!-- Validation Summary -->
<asp:ValidationSummary ID="ValidationSummary1" runat="server"
HeaderText="Validation errors:" ValidationGroup="Group1"/>
<!-- TextBox and its validator -->
Name: <asp:TextBox ID="TextBox1" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
ErrorMessage="Name is required" Text="*"
ControlToValidate="TextBox1" ValidationGroup="Group1"> />
<!-- Div that causes client-side validation when clicked -->
<div onclick="Validate();" >Validate Form</div>
The code above should should produce smth like that when validation is triggered:
Now let's take a look at the custom JS code that triggers the validation. There are couple ways to do that:
- Easy way - works for all validators from the same ValidationGroup:
function Validate()
{
// If no group name provided the whole page gets validated
Page_ClientValidate('Group1');
}
- If you want to validate only specific validators:
function Validate()
{
// Get the specific validator element
var validator = document.getElementById('RequiredFieldValidator1');
// Validate chosen validator
ValidatorValidate(validator);
// Update validation summary for chosen validation group
ValidatorUpdateIsValid();
ValidationSummaryOnSubmit(validationGroup);
}
May 6, 2011 07:15 by
ScottBelow is sample code showing how to send email from ASP.Net 4 (currently in beta as of this posting) using C#. With this code I am assuming that the server already has a local SMTP service installed, so I use "localhost" to relay the email.
Here is the SendMail.aspx page:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="SendMail.aspx.cs" Inherits="SendMail" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Message to:
<asp:TextBox ID="txtTo" runat="server"></asp:TextBox>
<br />
Message from:
<asp:TextBox ID="txtFrom" runat="server"></asp:TextBox>
<br />
Subject:
<asp:TextBox ID="txtSubject" runat="server"></asp:TextBox>
<br />
Message Body:
<br />
<asp:TextBox ID="txtBody" runat="server" Height="171px" TextMode="MultiLine"
Width="270px"></asp:TextBox>
<br />
<asp:Button ID="Btn_SendMail" runat="server" onclick="Btn_SendMail_Click"
Text="Send Email" />
<br />
<br />
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>
Here is the source code of the SendMail.aspx.cs page:
using System;
using System.Web.UI.WebControls;
using System.Net.Mail;
public partial class SendMail : System.Web.UI.Page
{
protected void Btn_SendMail_Click(object sender, EventArgs e)
{
MailMessage mailObj = new MailMessage(
txtFrom.Text, txtTo.Text, txtSubject.Text, txtBody.Text);
SmtpClient SMTPServer = new SmtpClient("localhost");
try
{
SMTPServer.Send(mailObj);
}
catch (Exception ex)
{
Label1.Text = ex.ToString();
}
}
}
Hope this tutorial can help!!
April 30, 2011 06:43 by
ScottIt is very much easier to apply CSS when we have ul,li elements as the HTML content. If we look into ASP.NET Menu Control till Version 3.5, its render as Table-TR-TD Tag. Though Table/Tr/Td is quite useful to display tabular data but sometime creates a big problem when we need to do more work with CSS. To overcome this problem we generally used CSS Friendly adapter to render the ASP.NET Control in ul/li mode.
ASP.NET 4.0 makes the things easier for web developer by providing “RenderingMode” properties. Here we can specify RenderMode of a ASP.NET Menu control. Which define the what will be the HTML Render Content Type. Bydefault mode is “List” which means control will be render as ul/li.
As per the above diagram we can see that there are three mode available. We can use any one of them as per the requirement.
Let’s see one small example by using the ASP.Net menu web control and check how it renders as HTML in ASP.Net 4.0. Assume that we are having the following piece of code
<asp:Menu runat="server" ID="customeMenu" RenderingMode="List" >
<Items>
<asp:MenuItem Text="File" Value="File"></asp:MenuItem>
<asp:MenuItem Text="Edit" Value="Edit"></asp:MenuItem>
<asp:MenuItem Text="View" Value="View"></asp:MenuItem>
<asp:MenuItem Text="WebSite" Value="WebSite"></asp:MenuItem>
</Items>
</asp:Menu>
This Menu control will be render as below html code in ASP.NET 4.0 as, we have mentioned “List” as the rendering mode.
<ul>
<li><a href="#">File</a></li>
<li><a href="#">Edit</a></li>
<li><a href="#">View</a></li>
<li><a href="#">WebSite</a></li>
</ul>
To test the above scenario run the web application that contain the menu control and after page rendered complete Right Click on view source of the aspx page. The output will be look like as bellow.
We can also generate the Menu Control as HTML Table like earlier version by using RenderingMode=”Table”.
So, for the same block of code,
<asp:Menu runat="server" ID="customeMenu" RenderingMode="Table" >
<Items>
<asp:MenuItem Text="File" Value="File"></asp:MenuItem>
<asp:MenuItem Text="Edit" Value="Edit"></asp:MenuItem>
<asp:MenuItem Text="View" Value="View"></asp:MenuItem>
<asp:MenuItem Text="WebSite" Value="WebSite"></asp:MenuItem>
</Items>
</asp:Menu>
HTML Rendered output will be as follows
<table >
<tr >
<td><table>
<tr>
<td >File</a></td>
</tr>
</table></td>
</tr><tr>
<td><table >
<tr>
<td>Edit</a></td>
</tr>
</table></td>
</tr><tr>
<td><table >
<tr>
<td >View</a></td>
</tr>
</table></td>
</tr><tr >
<td><table >
<tr>
<td>WebSite</a></td>
</tr>
</table></td>
</tr>
</table>
Note: With the above html content ASP.NET engine automatically adds few client side script along like onmouseover=”Menu_HoverStatic(this)” onmouseout=”Menu_Unhover(this)” onkeyup=”Menu_Key(this)” id=”customeMenun0″ with rendered menu items. Which helps the developer to handel the client side events.
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April 28, 2011 10:26 by
ScottError Message:
404 Not Found error messages are often customized by each website, especially very large ones, so keep in mind that this error may present itself in more ways than the common ones listed below
- "404 Error"
-"Page cannot be displayed"
-"Internet Explorer cannot display the webpage"
-"404: Not Found"
-"The page cannot be found"
-"Error 404: NOT FOUND"
-"HTTP 404 - File not found"
-"Not Found"
The 404 Not Found error displays inside the Internet browser window, just as web pages do.
Solution
1. Retry the web page by clicking the refresh/reload button or trying the URL from the address bar again. The 404 Not Found error has been known to appear on occasion even if there is no real issue so a simple refresh will often load the page you were looking for.
2. Check for errors in the URL. Often times the 404 Not Found error appears because the URL was typed wrong or the link that was clicked on points to the wrong URL.
3. Move up one directory level at a time in the URL until you find something. For example, if www.w.com/a/b/c.htm gave you the 404 Not Found error, move up to www.w.com/a/b/. If you get nothing here, move up to www.w.com/a/. This should lead you toward what you're looking for or at least confirm that it's no longer available.
4. If you move all the way up to the website's main page, try to run a search for the information you're looking for. If a search function isn't available, try finding your information by using links from this page to dig deeper into the site.
5. Test the page at downforeveryoneorjustme.com. Just enter the webpage in this online tool and it will tell you just that - if the site is down for everyone, or if the problem is on your end somewhere.
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There are many reasons why so many people choose HostForLife over any other web hosting provider each year. Whether you’re beginner or an experience webmaster, HostForLife offers the perfect solution for everyone.
You’ll have highly trained, skilled professional technical support people ready, willing, and wanting to help you 24 hours a day. Your web hosting account servers are monitored from three monitoring points, with two alert points, every minute, 24 hours a day, 7 days a week, 365 days a year. The followings are the list of other added-benefits you can find when hosting with us:
1. World-class 24x7 Customer Support
Will your hosting company promptly answer questions and resolve issues - at 3 am on a Sunday? Even some providers claiming “24x7” support will not - but HostForLife will. Our outstanding uptime is backed by true 24x7 customer support. An expertly trained technician will respond to your query within one hour, round the clock. You will also get qualified answers. Other hosting companies typically have very low - level support staff during the night or weekends. HostForLife always has knowledgeable, top - level support standing by, day or night, to give you the answers you need.
2. Commitment to Outstanding Reliability
Reliability, Stability, and Performance of our servers remain out TOP priority. Even our basic service plans are equipped with standard service level agreements for 99.99% uptime. Advanced options raise the bar to 99.99%. Our state-of-the-art data centers combine servers and SAN storage with full redundancy and operational tools with proprietary service management techniques. Full backup and recovery capabilities are implemented, including redundant power supplies, cooling and connectionsto major data networks.
3. “Right-size” plans for maximum value
HostForLife offers a complete menu of services. IT professionals select only what they need - and leave behind what they don’t. The result is an optimal blend of cost and performance. We offer IT professionals more advanced features and the latest technology - ahead of other hosting companies.
4. Profitable, Stable, Debt-free Business
Financial stability is the bedrock of a hosting provider’s ability to deliver outstanding uptime, cost-effective service plans and world-class 24x7 support. HostForLife’s customers are assured of our financial integrity and stability - a stark contrast to the ups and downs they may have experienced with other providers.
5. The Best Account Management Tools
HostForLife revolutionized hosting with Plesk Control Panel, a Web-based interfaces that provides customers with 24x7 access to their server and site configuration tools. Some other hosting providers manually execute configuration requests, which can take days. Plesk completes requests in second. It is included free with each hosting account. Renowned for its comprehensive functionally - beyond other hosting control panels - and ease of use, Plesk Control Panel is available only to HostForLife’s customers.
6. 30-Day Money Back Guarantee
HostForLife 30 day money back guarantee ensures you have the ability to cancel your account anytime within your first 30 days under our full 30 day money back guarantee (less one-time account setup free). So what are you waiting for? Sign up today, risk free…
7. Simplicity with FREE 1-Click Installation
HostForLife was designed with ease of use in mind. From one click installations of your favourite website applications to our much talked about drag and drop website builder, you can rest assure your stay with us is going to be a smooth one. HostForLife offers the most extensive set of scripts on the web allowing you to build complicated websites with little or no programming knowledge at all. From blogs to forums to powerful e-commerce solutions, Super Green has something that is right for you.