The TaskPlugin library is set of classes, interfaces, enumerations and attributes that collectively support the ITaskPlugin interface. The ITaskPlugin interface is a .NET interface created to demonstrate how to create a “Plug-in” architecture utilizing the Microsoft .NET framework.
The solution provided, Plug-in, includes 5 C# projects:
Step 1: Include a reference to the TaskPluginInterface.dll in your solution.
Step 2: Get the folder location for the plug-ins. I use \Plugins. Call the Utilities.GetPluginFolder() method.
Step 3: Get a list of plug-ins. Call Utilities.GetPlugins(folderName).
Step 4: Call the plug-ins Execute Method.
Option 1: Code from scratch.
Step 1: Include a reference to the TaskPluginInterface.dll in your solution.
Step 2: Create a class that inherits from ITaskPlugin.
public class RunCommand
: ITaskPlugin
{
}
Step 3: If you are using Visual Studio 2005 you can use the Intellisense or SmartTag to create the stub implementation of ITaskPlugin.
Step 4: Place your code in the Execute method.
Option 2: Use the PluginShellPlugin class.
Step 1: Rename the class to what ever name you want.
Step 2: Change the resource file strings to accurately describe your plug-in.
Step 3: Change the code in the DoWork() method.
The ITaskPlugin interface defines the methods, events, and properties that the plug-ins must implement.
Enumeration Name |
Description |
Execute |
Executes the task |
Enumeration Name |
Description |
Author |
The author of the plug-in |
Description |
The description of the plug-in |
Extension |
The file extension(s) that this plug-in handles. This is currently not used. |
Extension Description |
A description of the extension(s) that this plug-in handles. This is currently not used. |
Name |
The name of the plug-in. |
Schedule |
The schedule for the plug-in. This was created for a future project, the pluggable task scheduler. |
Version |
The version of the plug-in. |
Enumeration Name |
Description |
EventEnd |
This is used to notify the host about the ending of the Execute Method. |
EventException |
This is used to notify the host about any Exceptions that have occurred. |
EventProcessing |
This is used to notify the host about the processing of the Execute Method. |
EventStart |
This is used to notify the host about the starting of the Execute Method. |
The PluginAttribute class defines the class attributes that can be applied to a class that is implementing the ITaskPlugin interface.
This class defines on Attribute which is PluginType. The PluginType corresponds to the PluginType class.
Syntax:
[TaskPluginInterface.Plugin(PluginType.Executable)]
public class RunCommand
: ITaskPlugin
{
}
This enumeration is used as the return value of Execute method for the ITaskPlugin interface.
Enumeration Name |
Description |
Cancelled |
Indicates that the Execute method of the plug-in was cancelled. |
Exception |
Indicates that an exception was raised by the plug-in. |
Failed |
Indicates that the plug-in has failed. |
Ok |
Indicates that everything went OK with execute of the plug-in. |
This enumeration is used to indicate the type of plug-in that is being created. Applying the PluginType attribute to a class does not have an affect the functionality of the class. Its only purpose is to provide a classification of the plug-ins available for list boxes or separate functionality.
Enumeration Name |
Description |
Executable |
Indicates the plug-in is used for launching executables. |
Import |
Indicates the plug-in is used for importing data. |
SQL |
Indicates the plug-in is used for processing SQL statements. |
Unknown |
Denotes the type of plug-in is not known. |
The PluginEventArgs class provides information back to the plug-in host. This information is provided back to the plug-in host via one of the four events.
PluginEventArgs properties:
Name |
Description |
Indicates if the operation should be canceled. |
|
A message returned from the plug-in. |
|
Indicates the current progress of the plug-in. The Progress is returned as a struct which is defined in the Utilities class. |
|
An exception raised from the plug-in. |
The ScheduleConfig class provides functions that will load the schedule configuration.
Note: This was created for a future version of the application.
This Utilities class provides helper functions to interact with and discover plug-ins. All of the provided methods are static so there is no need to create an instance of the Utilities class.
Utilities class methods:
Method Name |
Description |
FileContainsPlugins |
Determines if the file contains at least one plug-in. There is one overload which allows you specify a PluginType. |
GetPlugin |
Returns a plug-in of the specified class from the specified file. |
GetPluginFileList |
Gets a list files that contain plug-ins within the specified directory. There is one overload which allows you specify a PluginType. |
GetPluginFolder |
Returns the plug-in directory. |
GetPlugins |
Gets a List of plug-ins from the specified file. There is one overload which allows you specify a PluginType. |
The FileCopy plug-in provides the ability to copy files that fit a mask from one directory to another.
This plug-in reads the configuration file (FileCopyPlugin.Settings.xml) for all of the Directory nodes listed in the Directories element.
Sample:
<Directories>
<Directory FromDir="C:\Temp\" ToDir="d:\Temp\" FileMask="*.*" />
<Directory FromDir="C:\Temp\junk" ToDir="d:\Temp\junk" FileMask="*.txt" />
<Directory FromDir="C:\Temp\junk" ToDir="d:\Temp\junk" FileMask="*.xyz" />
</Directories>
The following configuration contains three copy commands.
The PluginShell plug-in provides a class that contains everything needed to implement the ITaskPluginInterface.
The RunCommand plug-in provides the ability to execute processes using the System.Diagnostics.Process namespace.
This plug-in reads the configuration file (RunCommandPlugin.Settings.xml) for Command elements listed in the Commands node. Each command element has XmlChildNodes that correspond to parameters of the ProcessStartInfo struct of the Process object.
The TaskPluginTest is sample application that demonstrates the use of the TaskPluginInterface library. This application utilizes the TaskPluginInterface .Utilities to load the list of application plug-ins. In addition, this application displays the plug-in meta-data, executes the plug-in and handles events from the plug-in.
Version |
Date |
|
What was done |
1.0 |
4/21/07 |
|
Initial Release. |