Navigation:  I Want To... > Miscellaneous > Add a custom external application launcher

Use Case

Relevant Architecture

Relevant Types

Sample Code

using System.Diagnostics;

using System.IO;

using ClearCanvas.Common;

using ClearCanvas.Desktop;

using ClearCanvas.ImageViewer.Externals;

using ClearCanvas.ImageViewer.Externals.General;

using Path=System.IO.Path;

 

// ... (other using namespace statements here)

 

namespace MyPlugin.Miscellaneous

{

   /// <summary>

   /// Defines your custom launcher - the external class, the configuration component for it,

   /// and the descriptive label to be used in the Add External dropdown.

   /// </summary>

   [ExtensionOf(typeof (ExternalFactoryExtensionPoint))]

   public class MyExternalApplicationLauncherFactory : ExternalFactoryBase<MyExternalApplicationLauncher>

   {

      public MyExternalApplicationLauncherFactory() : base("Custom launcher") {}

 

      public override IExternalPropertiesComponent CreatePropertiesComponent()

      {

         return new MyExternalApplicationLauncherProperties();

      }

   }

 

   /// <summary>

   /// This is the actual external class that launches the application.

   /// </summary>

   public class MyExternalApplicationLauncher : ExternalBase

   {

      private string _command;

 

      public string Command

      {

         get { return _command; }

         set { _command = value; }

      }

 

      protected override bool CanLaunch(IArgumentHintResolver hintResolver)

      {

         // check if the supplied hints are enough to launch the external using the current configuration

         return true;

      }

 

      protected override bool PerformLaunch(IArgumentHintResolver hintResolver)

      {

         string filename = Path.GetTempFileName();

 

         // write the desired input to the file

         File.WriteAllText(filename, string.Format("<xml>{0}</xml>", hintResolver.Resolve("$FILENAME$")));

 

         // start the external and tell it the file containing input

         Process.Start(_command, string.Format("\"{0}\"", filename));

 

         return true;

      }

 

      public override string GetState()

      {

         // serialize the external's configuration to a string

         return _command;

      }

 

      public override void SetState(string state)

      {

         // deserialize the external's configuration from a string

         _command = state;

      }

   }

 

   public sealed class MyExternalApplicationLauncherPropertiesViewExtensionPoint : ExtensionPoint<IApplicationComponentView> {}

 

   /// <summary>

   /// This is just an ApplicationComponent for editing the properties of your type of external.

   /// </summary>

   [AssociateView(typeof (MyExternalApplicationLauncherPropertiesViewExtensionPoint))]

   public class MyExternalApplicationLauncherProperties : ExternalPropertiesComponent<MyExternalApplicationLauncher>

   {

      private string _command;

 

      public string Command

      {

         get { return _command; }

         set

         {

            if (_command != value)

            {

               _command = value;

               this.NotifyPropertyChanged("Command");

            }

         }

      }

 

      public override void Load(MyExternalApplicationLauncher external)

      {

         base.Load(external);

 

         // populate this component from the external

         _command = external.Command;

      }

 

      public override void Update(MyExternalApplicationLauncher external)

      {

         // update the external using the values specified in this component

         external.Command = _command;

 

         base.Update(external);

      }

   }

}

Remarks

The ExternalFactoryExtensionPoint class is the main extension point where you can install your custom external application launchers. Each IExternalFactory is responsible for constructing new instances of an IExternal - each entry you see in the list of external applications - as well as the configuration panel that you see when you edit an entry in that list. A custom implementation of an External must provide a way of serializing/deserializing the configuration to a string and, of course, embody the logic to actually launch the application after figuring out what to do with the provided hints. If you need more hints than what the ExternalBase<T> base class provides, then you can inherit from an even lower level and directly access the presentation images and/or display sets being viewed.

Examples in Code Base