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Have you ever wanted to be able to add scripting to your application?  So your users can write a script and you can have it run inside it, adding menus, etc. - like Microsoft Visual Basic for Applications allows in Office.

This is a preliminary article, I'll try to rewrite this but I just took a 20 minute break from work (need to have something done for tomorrow - so yes, still working at 10PM!  GRR) and finally managed to get scripting using Microsoft.VSA working from a C# application.  Apologies for the lack of tabs in the formatting and lack of explanation.

This is missing the ability to access anything in the running application - you need to register a global item (in the same way as code items and references are added) to do that - then it is exposed as an object inside the environment running the script.

Add references to Microsoft.VisualBasic.Vsa and Microsoft.Vsa (when I repost I'll be using JScript.NET - never fear!) and add the following using clauses:

using System.Reflection;

using Microsoft.Vsa;

using Microsoft.Win32;

And then add the following code to a button or similar (with a textbox to enter your script in) - this will create a scripting engine object, then run your script inside it.  The best test is to show a message using MessageBox.Show(""); (remember though, it's VB!)

ScriptEngine eng = new ScriptEngine();
eng.Start();
IVsaCodeItem c = eng.CreateCodeItem(
"ScriptItem");
c.SourceText = textBox1.Text; //Where this is a simple vb.net script with a class called Script and a Sub called Main
eng.Run();

And now, the main code chunk snippet that is the scripting engine:

public class ScriptEngine : IVsaSite
{
private IVsaEngine Engine;
public ScriptEngine()
{
Start();
}

public void Start()
{
try
{
Engine =
new Microsoft.VisualBasic.Vsa.VsaEngine();
Engine.RootMoniker =
"myapp://net.nullify.www/ScriptEngine";
Engine.Name =
"vsaEngine";
Engine.RootNamespace =
"VsaEngine";
Engine.Site =
this;
Engine.InitNew();
CreateReference(
"Mscorlib.dll");
CreateReference(
"System.dll");
CreateReference(
"System.Windows.Forms.dll");
CreateReference(
"System.Data.dll");
CreateReference(
"System.Drawing.dll");
CreateReference(
"System.XML.dll");
}
catch (VsaException ex)
{
MessageBox.Show(
"Scripting engine error: "+ex.Message);
}
}

public IVsaReferenceItem CreateReference(string assemblyName)
{
IVsaReferenceItem item = (IVsaReferenceItem)Engine.Items.CreateItem(assemblyName, VsaItemType.Reference, VsaItemFlag.None);
item.AssemblyName = assemblyName;
return item;
}

public IVsaCodeItem CreateCodeItem(string itemName)
{
try
{
IVsaCodeItem item = (IVsaCodeItem)Engine.Items.CreateItem(itemName, VsaItemType.Code, VsaItemFlag.Class);
return item;
}
catch (VsaException ex)
{
MessageBox.Show(
"Problem creating the code item: "+ex.Message);
}
return null;
}

public void Run()
{
if (Engine.Compile())
{
Engine.Run();
Type type = Engine.Assembly.GetType(
"VsaEngine.Script");
MethodInfo method = type.GetMethod(
"Main");
method.Invoke(
null, null);
}
}

#region IVsaSite Members

public object GetEventSourceInstance(string itemName, string eventSourceName)
{
// TODO: Add ScriptEngine.GetEventSourceInstance implementation
return this;
}

public object GetGlobalInstance(string name)
{
// TODO: Add ScriptEngine.GetGlobalInstance implementation
return null;
}

public void Notify(string notify, object info)
{
// TODO: Add ScriptEngine.Notify implementation
}

public bool OnCompilerError(IVsaError error)
{
MessageBox.Show(
"["+error.Line+"] Compiler error: "+error.Description);
return true;
}

public void GetCompiledState(out byte[] pe, out byte[] debugInfo)
{
// TODO: Add ScriptEngine.GetCompiledState implementation
pe = null;
debugInfo =
null;
}

#endregion

}

And finally to test this you can use the following code:

imports System
imports System.Diagnostics

module Script
sub Main()
MessageBox.Show("Boo")
end sub
end module

Permalink  2 Comments 

Congratulations by gadafi10 at 22/05/2006 14:54:57
Hi, It's brilliant your example. It has helped me a while. Anyway, do you know where I can get more info about VSA??? I will apreciate a lot. Cheers

Good work by Piter at 19/10/2007 11:38:06
Hi, good work. This is another way to achieve this goal: http://www.codeproject.com/useritems/ScriptNET.asp