Sunday, September 15, 2013

How to create link button and event handler programmatically in user control

We often have the scenario that it need to generate LinkButtons in our web application depend on user role or action. This post explain you step by step how to create link buttons and their event handler dramatically in user control and use in .aspx page as below image :
Dynamic link buttons
First, create one user control ("LinkButtonControl.ascx") and copy the following code to that control. It uses PlaceHolder contron that is to store dynamically added server controls on the Web page.
<fieldset style="width: 200px;">
    <legend>Dynamic Links</legend>
    <ul>
        <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
    </ul>
</fieldset>
In code-behind, it should look like as below :
public partial class LinkButtonControl : System.Web.UI.UserControl
{
    //Declare event handler 
    public delegate void LinkButtonEventHandler(object sender, EventArgs e);
    public event LinkButtonEventHandler LinkButtonClick;
    //Create generic list object 
    List<LinkControl> linkControlList = new List<LinkControl>();

    protected void Page_Load(object sender, EventArgs e)
    {
        //Add the sample data to generic list
        linkControlList.Add(new LinkControl { Name = "aboutus", Title = "About Us", Url = "aboutus.aspx" });
        linkControlList.Add(new LinkControl { Name = "contactus", Title = "Contact Us", Url = "contactus.aspx" });
        linkControlList.Add(new LinkControl { Name = "tou", Title = "Term of use", Url = "TOU.aspx" });
        CreateLinkButtons();
    }
    public void CreateLinkButtons()
    {
        foreach (var link in linkControlList)
        {
            //Create LinkButton programmatically 
            LinkButton lb = new LinkButton();
            lb.ID = link.Name;
            lb.Text = link.Title;
            lb.CommandArgument = link.Url;
            lb.Click += new EventHandler(this.LinkButtonClick);
            //Add LinkButton to PlaceHolder
            PlaceHolder1.Controls.Add(new LiteralControl(@"<li>"));
            PlaceHolder1.Controls.Add(lb);
            PlaceHolder1.Controls.Add(new LiteralControl(@"</li>"));
        }
    }
    protected void LinkButton_Click(object sender, EventArgs e)
    {
        if (LinkButtonClick != null)
            LinkButtonClick(sender, e);
    }
}
//Data Transfer Object class  
public class LinkControl
{
    public string Name{get; set; }
    public string Title { get; set; }
    public string Url { get; set; }
}
Second, create one .aspx page("UserControlTest.aspx") and add the follow CSS to <head> tag for link button layout.
<style type="text/css">
    ul 
    {
        list-style-type: none;
        margin: 0;
        padding: 0;
    }
</style>
Finally, drag and drop our user control ("LinkButtonControl.ascx") to .aspx page and add "OnLinkButtonClick" event manually as below :
<uc1:LinkButtonControl ID="LinkButtonControl1" runat="server" OnLinkButtonClick="LinkButtonControl1_Click" />    
Copy the following code snippet to code-behind for event implementation.   
protected void LinkButtonControl1_Click(object sender, EventArgs e)
{
    LinkButton lb = sender as LinkButton;
    if (lb != null)
        Response.Redirect(lb.CommandArgument);
}
That's it.

Hope this helps
SI THU WIN

Sunday, July 21, 2013

How to create and read Xml in asp.net

We often have to deal with Xml message when our applications are integrated with SMS Api, Email Api or Payment Api. At that time, we prepare Xml message and feed the services. Likewise, it gets the Xml message from the service of API and extracts the message from Xml message for on-going process. This post explain step by step how to create Xml message and read the message from Xml elements.

First, copy and paste the following Xml message to new file "XmlMessage.xml" in "App_Data" folder in your project. You see "[xxxxxxx]" and it is place holder for data we put.
<?xml version="1.0" encoding="utf-8" ?>
<paymentService version="1.4" merchantCode="[merchantCode]">
  <reply>
    <orderStatus orderCode="[orderCode]">
      <payment>
        <paymentMethod>[paymentMethod]</paymentMethod>
        <amount value="[value]" currencyCode="[currencyCode]" exponent="[exponent]"/>
        <lastEvent>[lastEvent]</lastEvent>
        <CVCResultCode description="[CVCResultCode]"/>
        <ISO8583ReturnCode code="[ISO8583ReturnCode]" description="[ISO8583ReturnDescription]"/>
      </payment>
    </orderStatus>
  </reply>
</paymentService>
Second, we need to add Textbox server control to .aspx page as below:
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="txtXml" runat="server" Height="250px" Width="576px" 
            TextMode="MultiLine"></asp:TextBox>
    </div>
    </form>
</body>
Third, copy and paste the following code in code behind.
protected void Page_Load(object sender, EventArgs e)
{
    //Set the data here.
    string merchantCode = "MYMERCHANT";
    string orderCode = "T0211234";
    string paymentMethod = "ECMC-SSL";
    string value = "162095";
    string currencyCode = "GPB";
    string exponent = "2";
    string lastEvent = "REFUSED";
    string CVCResultCode = "NOT SUPPLIED BY SHOPPER";
    string ISO8583ReturnCode = "33";
    string ISO8583ReturnDescription = "CARD EXPIRED";

    string xmlMsg = GetXmlMessage();
    //Fill the data in place holder in Xml message.
    xmlMsg = xmlMsg.Replace("[merchantCode]", merchantCode);
    xmlMsg = xmlMsg.Replace("[orderCode]", orderCode);
    xmlMsg = xmlMsg.Replace("[paymentMethod]", paymentMethod);
    xmlMsg = xmlMsg.Replace("[value]", value);
    xmlMsg = xmlMsg.Replace("[currencyCode]", currencyCode);
    xmlMsg = xmlMsg.Replace("[exponent]", exponent);
    xmlMsg = xmlMsg.Replace("[lastEvent]", lastEvent);
    xmlMsg = xmlMsg.Replace("[CVCResultCode]", CVCResultCode);
    xmlMsg = xmlMsg.Replace("[ISO8583ReturnCode]", ISO8583ReturnCode);
    xmlMsg = xmlMsg.Replace("[ISO8583ReturnDescription]", ISO8583ReturnDescription);
    txtXml.Text = xmlMsg;
    ReadXmlMessage(xmlMsg);
}

public string GetXmlMessage()
{
    //Get Xml message from file.
    string XmlFile = "~/App_Data/XmlMessage.xml";
    StreamReader sr = new StreamReader(Server.MapPath(XmlFile));
    string str = sr.ReadToEnd();
    return str;
}

public void ReadXmlMessage(string xmlMsg)
{
    if (!string.IsNullOrEmpty(xmlMsg))
    {
        //Read the data from Xml elements.
        XmlDocument document = new XmlDocument();
        document.LoadXml(xmlMsg);
        string merchantCode = document.GetElementsByTagName("paymentService")[0].Attributes["merchantCode"].Value;
        string orderCode = document.GetElementsByTagName("orderStatus")[0].Attributes["orderCode"].Value;
        string paymentMethod = document.SelectSingleNode("//paymentMethod").InnerText;
        string value = document.GetElementsByTagName("amount")[0].Attributes["value"].Value;
        string currencyCode = document.GetElementsByTagName("amount")[0].Attributes["currencyCode"].Value;
        string exponent = document.GetElementsByTagName("amount")[0].Attributes["exponent"].Value;
        string lastEvent = document.SelectSingleNode("//lastEvent").InnerText;
        string CVCResultCode = document.GetElementsByTagName("CVCResultCode")[0].Attributes["description"].Value;
        string ISO8583ReturnCode = document.SelectSingleNode("//ISO8583ReturnCode").Attributes["code"].Value;
        string ISO8583ReturnDescription = document.SelectSingleNode("//ISO8583ReturnCode").Attributes["description"].Value;
    }
}
I use XmlNode.SelectSingleNode method to get xml data. It selects the first XmlNode that matches the XPath expression. The first XmlNode that matches the XPath query or null if no matching node is found.
I used aslo XmlDocument.GetElementsByTagName method to return an XmlNodeList containing a list of all descendant elements that match the specified Name. If no nodes match name, the returned collection will be empty.

Finally, run and see the result. It look like as below:

Sunday, May 5, 2013

How to use Pass-through authentication to Access Resources in different domain environment

Our web application often need to access local or network resources in production environment. For example, our application have to access file server for read/write access in different domain (not in a domain). In the above cases, we can use mirrored local accounts known as "Pass-through authentication". With this approach, you use two local accounts with the same user name and password on both servers (such as web server and file server). For network resources in the same domain, see previous post. Let's start here.

Step 1. Create a New User Account on Web Server

1. Click Start, select Administrative Tools and click Computer Management.
2. In Computer Management, click Local Users and Groups.
3. Double click the Users folder.
4. Right click in the users list and click New User.
5. Fill in the information for the new user (e.g. newacc) and click Create.


6. Make that account a member of the IIS_IUSRS group (In IIS 6, it is IIS_WPG group instead of IIS_IUSRS) as below:


Step 2. Create an Application Pool with a Custom Identity

1. Right click on Applicaton Pools node underneath the Machine node and Click Add Application Pool...
2. Type the name of new application pool (e.g. NewAppPool) on Add Application Pool dialog and press OK.


3. Select new application pool (NewAppPool) under Application Pools node and click Advanced Settings.


4. Advanced Settings dialog will appear and select the "Identity" list item and click the ellipsis (the button with the three dots).


5. Select Custom account option and press Set..


6. Type the new created account information (newacc) and press OK.


Step 3. Configure Your Application to Run in the New Application Pool

1. Go to IIS, click on your web application and click "Advanced Settings".
2. Click the ellipsis (the button with the three dots) on Application Pool item list.


3. Select the new application pool (NewAppPool) on Select Application Pool dialog and press OK.


Step 4. Create a New User Account on File Server

1. Create a local account with the same username and password as the one in Web Server (Step 1).

Step 5. Set permission of folder on File Server

1. Go to the given folder (e.g. FileShare) in File Server
2. Right click the folder and select "Properties"
3. Select the "Security" tab and click Edit


4. Click Add for new user account.


5. Type the created user account (newacc) and click Check Names and OK.


6. Set permission for that created local accout as below:


7. Click OK to finish.

By doing this, the file or directory you selected in file server will now allow the custom account  identity access from your web application in web farm.

Reference :
How To: Create a Service Account for an ASP.NET 2.0 Application
Understanding Built-In User and Group Accounts in IIS 7

Saturday, March 23, 2013

How to use Network Service Account to Access Resources in ASP.NET in the same domain

Our web application often need to access local or network resources in production environment. For example, our application have to access file server for read/write access in the same domain. In case, web application upload and save user account photo or document such as excel and word file. At that time, it need the Network Service Account that is least privileged, although it have network credentials which means that you can use it to authenticate against network servers.

By default, Microsoft Internet Information Services (IIS) 6.0 on Windows Server 2003 runs ASP.NET applications in application pools that use the NT AUTHORITY\Network Service account identity. This account is a least privileged machine account with limited permissions and an application that runs using this account has restricted access, network credentials, which means you can use it to access network resources and remote databases by using Windows authentication. The network resources must be in the same domain as your Web server or in a trusted domain. Normally, the Application Pool Identity in IIS7 is "ApplicationPoolIdentity" by default and in IIS5 or IIS6, is "NetworkService" by default. Let's start here, to use the NT AUTHORITY\Network Service machine account to access local and network resources in Web Farm.

1. Configuring IIS Application Pool Identities
First, we check what Application Pool our web application use as follow:


Go to IIS, click on your web application and click "Advanced Settings".


Now, you see your application use "DefaultAppPool" Application Pool. If you want to change it to another, click the ellipsis (the button with the three dots). The following dialog appears.


Select the Application Pool you want from the combo box and Press OK button. Now, we know already what Application pool we used. Then we change the Identity Type for Application Pool.
Go to IIS, select "Application Pool" node and then select Application Pool you want to change as shown below:


Click "Advanced Setttings" and you will see the following dialog box:


Now, Identity is "NetworkService" already. Otherwise, select the "Identity" list item and click the ellipsis (the button with the three dots). The following dialog appears.


Select the Identity Type "NetworkService" from the combo box and press OK button. So, we finished marking sure that our web application that run using "NetworkService" Application Pool Identity.

2. Securing Resources
Whenever a new Application Pool is created, the IIS management process creates a security identifier (SID) that represents the name of the Application Pool itself. For example, if you create an Application Pool with the name "MyNewAppPool," a security identifier with the name "MyNewAppPool" is created in the Windows Security system. From this point on, resources can be secured by using this identity. However, the identity is not a real user account; it will not show up as a user in the Windows User Management Console.
Let's start giving permission to folder in remote server here.

1. Open Windows Explorer
2. Select a file or directory.
3. Right click the file and select "Properties"
4. Select the "Security" tab
5. Click the "Edit" and then "Add" button



6. Click "Locatoins" and make sure you select your domain and then enter the Network Service account.


The Network Service account's credentials are of the form DomainName\AspNetServer$, where DomainName is the domain of the ASP.NET server and AspNetServer is your Web server name.For example, if your ASP.NET application runs on a server named SVR1 in the domain CONTOSO, the Network Service account is CONTOSO\SVR1$.

7. Click the "Check Names" button and click "OK".
8. Set permission for new account as below:


By doing this, the file or directory you selected in file server will now allow the Network Service identity access from your web application.

Reference :

How To: Use the Network Service Account to Access Resources in ASP.NET
Application Pool Identities