Smartclient is a nice concept for occasionally connected applications. A windows forms application or a WPF application can be made available for easy deployment from a webserver, file share etc.. Not only that it can also serve as an update server too.
Though Wix ClickThrough is another concept for similar use, both got unique advantages. And I feel clickonce is the option for today while and clickthrough is evolving.
In this post I would like describe some of the basic concepts of clickonce. I feel this would be useful for anyone starting with clickonce. Let us start with a bit basic theory then move on to infrastructure required to do this and then to an example.
Concept
The core ClickOnce deployment architecture is based on two XML manifest files –Application manifest and Deployment manifest.
The application manifest describes the application itself, including the assemblies, the dependencies and files that make up the application, the required permissions, and the location where updates will be available.
The deployment manifest describes how the application is deployed, including the location of the application manifest, and the version of the application that clients should run.
Following diagram shows how versions will be maintained in webserver. Each version will have its own Application Manifest file.
At any time deployment manifest points to one of the versions. Deployment manifest contains an URI which client tries to access from web browser. Click once infrastructure sends pointed version to client. If client contains that version previously then download doesn’t takes place, rather application is launched in client. Else assemblies of that version will be copied to client.
In Client each version is stored in separate directory in application cache which is typically at “C:\Documents and Settings\username\Local Settings\Apps\2.0\<xx>”. In addition click once application gets added to add/remove programs (if install option is selected in deployment manifest). In such case application automatically gets added to start menu also. Applications also run under Code Access Security purview. By default click once application gets deployed with Full trust permissions. However this can be tuned in application manifest.
Also click once applications can be updated automatically. Assume that client has 1.0.0.0 version installed. Click once applications can be configured to check for new updates during start up (Other options are also available like, after start up, periodically etc.). During start up if application detects if deployment manifest is pointing to new version. If so then it prompts user to update to new version. If user prefers to update new version is downloaded and made as default version. Incase user is not comfortable with updated version, he or she can prefer to un-install latest update and rollback to previous version. This roll back can be done as many times till lower version is available.
In case of large applications downloading entire application in one lot may not be very much acceptable. For such scenarios click once offers optional group mechanism. With this initial download happens for required assemblies only. Options groups will be downloaded on demand.
With this background let us move to infrastructure needed for this.
Infrastructure
Click expects .Net 3.0 to be available in target applications. If your application depends on higher version of .Net framework, then that becomes as necessary pre-requisite. Pre-requisites can be handled using bootstrapper. I will not cover bootstrap here. Let us assume required .Net framework version is available in client machine.
As mentioned above clickonce installation is nothing but “target assemblies + application manifest” + “deployment manifest”. Assemblies are built by developer. Then manifests can be built using mage.exe or mageui.exe. This is part of Windows SDK. Thus if you have Visual Studio 2005/2008 installed on your machine then you have both of these tools.
Apart from these developer also needs a “Personal Information Exchange (.pfx)” file to sign manifests. Signing manifests is mandatory. You may find this post useful to create a pfx file.
Thus to summaries this section. We need following set of files to create click once installation setup
- Application assemblies
- Personal Information Exchange File (pfx)
- mege.exe or mageUI.exe
Now let us start on example.
Example 1 - Basic
Let us take a forms application. As a first step let us try to create a clickonce installation setup for this forms application.
Just start Visual Studio and create a forms application by name “MyWebForm”. Just change Form title to “MyWebForm”. That is it nothing else. Build Release version. So MyWebFormApp.exe is the only file we want to create clickonce installation setup.
In IIS create a virtual directory by name MyWebForm. Under that create a subdirectory by name “1.0.0.0”. And copy MyWebFormApp.exe to that folder.
Now start mageui.exe from “C:\Program Files\Microsoft SDKs\Windows\<v6.0A>\Bin\”.
Create application manifest
- Click on File – > New – > Application Manifest
- Enter Name as MyWebFormApp
- Enter version as 1.0.0.0
- Select ‘Files’ from list box then select application directory. In this case it is “C:\Inetpub\wwwroot\MyWebForm\1.0.0.0”
- Click on populate.
- Then save manifest to folder 1.0.0.0 as “MyWebFormApp.exe.manifest”. MageUI prompts to sign application before saving. Select pfx file and click on save.
Create deployment manifest
- Click on File – > New – > Deployment Manifest
- Enter Name as MyWebFormApp
- Enter version as 1.0.0.0
- Select ‘Description’ from list box enter product name
- Select ‘Deployment Options’ from list box enter start location as “http://<webserver>/MyWebForm/MyWebForm.application”
- Select ‘Update Options’ from listbox and check on “Before Application Starts”
- Select ‘Application Reference’ from listbox and click on ‘Select Manifest’
- Select “MyWebFormApp.exe.manifest” from “C:\Inetpub\wwwroot\MyWebForm\1.0.0.0\” folder
- Then save manifest to folder “C:\Inetpub\wwwroot\MyWebForm\” as “MyWebForm.application”. MageUI prompts to sign application before saving. Select pfx file and click on save.
Installing first version
Open browser and browse to “http://<webserver>/MyWebForm/MyWebForm.application”
A window pops us prompting to install. Click on install. Application starts automatically and form is shown
You can also observe a new start menu short cut and an entry in Add/Remove programs.
So that is quite simple. Now let us add an optional package.
Example 2 – Optional group
Before we proceed uninstall application installed in last step from Add/Remove programs.
Add another project
Now let us create another form project to solution file by name “MyWebFormOptional1”.
Add reference of this project to main project.
Also add a button to main form MyWebFormApp. In button click event add code to launch second form.
private void button1_Click(object sender, EventArgs e)
{
MyOptionalForm1 opt1 = new MyOptionalForm1();
opt1.ShowDialog();
}
Update code to Dynamically load assembly
Idea here is to make MyWebFormOptional1 as optional group. Thus when click once application is downloaded first time only MyWebFormApp gets downloaded. Upon clicking on button “MyWebFormOptional1.exe” gets downloaded.
In order to this we use Application.LoadFile method. Copy paste following code in MyWebForm.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Reflection;
using System.Deployment.Application;
using System.Security.Permissions;
using System.IO;
using MyWebFormOptional1;
namespace MyWebFormApp
{
public partial class MyWebForm : Form
{
Dictionary<String, String> DllMapping = new Dictionary<String, String>();
[SecurityPermission(SecurityAction.Demand, ControlAppDomain = true)]
public MyWebForm()
{
InitializeComponent();
DllMapping["MyWebFormOptional1"] = "MyWebFormOptional1";
AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
}
/// <summary>
/// Use ClickOnce APIs to download the assembly on demand.
/// </summary>
/// <param name="sender"></param>
/// <param name="args"></param>
/// <returns></returns>
private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
Assembly newAssembly = null;
if (ApplicationDeployment.IsNetworkDeployed)
{
ApplicationDeployment deploy = ApplicationDeployment.CurrentDeployment;
//MessageBox.Show(args.Name);
// Get the assembly name from the Name argument.
string[] nameParts = args.Name.Split(',');
string assemblyName = nameParts[0];
string downloadGroupName = DllMapping[assemblyName];
try
{
deploy.DownloadFileGroup(downloadGroupName);
}
catch (DeploymentException de)
{
MessageBox.Show("Downloading file group failed. Group name: " + downloadGroupName + "; Assembly name: " + args.Name);
throw (de);
}
// Load the assembly.
// Assembly.Load() doesn't work here, as the previous failure to load the assembly
// is cached by the CLR. LoadFrom() is not recommended. Use LoadFile() instead.
try
{
if (File.Exists(Application.StartupPath + @"\" + assemblyName + ".exe"))
newAssembly = Assembly.LoadFile(Application.StartupPath + @"\" + assemblyName + ".exe");
else if (File.Exists(Application.StartupPath + @"\" + assemblyName + ".dll"))
newAssembly = Assembly.LoadFile(Application.StartupPath + @"\" + assemblyName + ".dll");
}
catch (Exception e)
{
throw (e);
}
}
else
{
//Major error - not running under ClickOnce, but missing assembly. Don't know how to recover.
throw (new Exception("Cannot load assemblies dynamically - application is not deployed using ClickOnce."));
}
return (newAssembly);
}
private void button1_Click(object sender, EventArgs e)
{
MyOptionalForm1 opt1 = new MyOptionalForm1();
opt1.ShowDialog();
}
}
}
Build application and copy MyWebFormApp.exe and MyWebFormOptional1.exe to 1.0.0.0 folder.
Update Application manifest
Open MyWebFormApp.exe.manifest file from 1.0.0.0 folder in MageUI.exe.
Select ‘Files’ from list box then populate files again. Now “MyWebFormOptional1.exe ” gets added.
Click on checkbox to select this file as optional. And enter “MyWebFormOptional1” as group. Save application manifest.
Update deployment manifest
Then open deployment manifest. Select ‘Application Reference’ from listbox and click on ‘Select Manifest’. Select same manifest again and save manifest once again.
Installing second version
- Open browser and browse to “http://<webserver>/MyWebForm/MyWebForm.application”
- A window pops us prompting to install. Click on install. Application starts automatically and form is shown
- Now open application cache at C:\Documents and Settings\username\Local Settings\Apps\2.0\<xx>” and observe that only MyWebFormApp.exe is downloaded.
- Now click on button to open MyWebFormOptional1. Window opens.
- Again check application cache. This time observe that application downloads second form automatically.
Example 3 – Update
Now let us target on auto updating application to new version. Don’t un-install previous application.
- Create a new folder under C:\Inetpub\wwwroot\MyWebForm\ as 1.0.1.0
- Update AssemblyInfo.cs file in solution for both project as
[assembly: AssemblyVersion("1.0.1.0")]
[assembly: AssemblyFileVersion("1.0.1.0")]
- Build application and copy MyWebFormApp.exe and MyWebFormOptional1.exe to 1.0.1.0 folder.
- Create Application manifest. But ensure to set version as 1.0.1.0 and also files are populated from 1.0.1.0 folder
- Update deployment manifest by selecting manifest from 1.0.1.0 folder in “Application Reference” pane.
Now launch application from start menu. This time user will be prompted with following dialog.
Hope you found this post useful.
