this is a known restriction. as there is little active development on vsa
its not likely to be lifted. the problem i believe is that the eval code is
not running in the correct context, so the global data is not found.
the simple fix for you is to switch from context based global data to
instance based global data. this means instead of calling static functions,
you call a static that returns an object that has props for the global data
(I generally pass the global objects to the constructor) . then call your
script methods off the class instance.
-- bruce (sqlwork.com)
"Tiaan via .NET 247" <anonymous (AT) dotnet247 (DOT) com> wrote
The C# code below shows a problem I'm having with the VSA engine where a
global object seems to get lost during script evaluation. It looks like the
engine recognizes the name of the global object, but simply returns null
when accessing it from an evaluation string -- although it works just fine
when accessing the global object from within other code items (as long as
those items are not evaluated themselves).
The example code can be compiled into a console executable that takes a
single argument as input from the command line (e.g., compile with "csc.exe
/t:exe ExampleCode.cs /r:Microsoft.JScript.dll,Microsoft.Vsa.dll"), which in
turn is evaluated as some JScript code. To illustrate the problem, the
supplied argument gets executed in four different ways. Running the
application with an argument like "System.Console.WriteLine(123);" would
produce the following output:
Executing code directly...
123
Executing code as a function...
123
Evaluating code as a function...
123
Evaluating code directly...
123
Done
However, when trying to access the global object, named "globStrDict", with
an argument such as "System.Console.WriteLine(globStrDict != null);" would
show the problem:
Executing code directly...
True
Executing code as a function...
True
Evaluating code as a function...
False
Evaluating code directly...
False
Done
Obviously, an argument such as
"System.Console.WriteLine(globStrDict.Count);" results in an exception as
soon as it hits the first evaluation point in the application. Why does the
evaluator know that the global object exists, but not return a reference to
it? Is there any way to access the global object with a simple call to
JScriptEvaluate so that I don't need to compile the code that needs to be
evaluated?
-- Tiaan.
==============================
using System;
using System.Collections.Specialized;
using Microsoft.Vsa;
using Microsoft.JScript;
using Microsoft.JScript.Vsa;
class ScriptSite : IVsaSite
{
private StringDictionary m_StringDictionary = new StringDictionary();
public object GetGlobalInstance(string name)
{
if (name == "globStrDict")
return m_StringDictionary;
return null;
}
public void GetCompiledState(out byte[] pe, out byte[] dbgInfo)
{
pe = null; dbgInfo = null;
}
public object GetEventSourceInstance(string itemName, string sourceName)
{
return null;
}
public void Notify(string notify, object info) {}
public bool OnCompilerError(IVsaError error)
{
Console.WriteLine("Error: {0}", error.Description);
return false;
}
}
class ScriptGlobals
{
public static void Main(string[] args)
{
if (args.Length != 1)
{
Console.WriteLine("USAGE: <ThisAppName> <JScriptCode>");
Console.WriteLine("EXAMPLE: <ThisAppName> " +
"\"System.Console.WriteLine(globStrDict.Count);\"" );
return;
}
string code = args[0];
try
{
VsaEngine eng = new VsaEngine();
eng.RootMoniker = "ScriptGlobals://JScript";
eng.Site = new ScriptSite();
eng.InitNew();
eng.RootNamespace = "blah";
eng.Name = "ScriptGlobals JScript Engine";
IVsaReferenceItem refItem;
refItem = (IVsaReferenceItem)eng.Items.CreateItem(
"mscorlib", VsaItemType.Reference, VsaItemFlag.None);
refItem.AssemblyName = "mscorlib.dll";
refItem = (IVsaReferenceItem)eng.Items.CreateItem(
"system", VsaItemType.Reference, VsaItemFlag.None);
refItem.AssemblyName = "System.dll";
IVsaGlobalItem globItem;
globItem = (IVsaGlobalItem)eng.Items.CreateItem(
"globStrDict", VsaItemType.AppGlobal, VsaItemFlag.None);
globItem.TypeString =
"System.Collections.Specialized.StringDictionary";
IVsaCodeItem codeItem;
codeItem = (IVsaCodeItem)eng.Items.CreateItem(
"intro", VsaItemType.Code, VsaItemFlag.None);
codeItem.SourceText = "import System;" +
"function WrapperFunc() { " + code + " } " +
"System.Console.WriteLine(\"Executing code directly...\");";
codeItem = (IVsaCodeItem)eng.Items.CreateItem(
"code", VsaItemType.Code, VsaItemFlag.None);
codeItem.SourceText = code;
codeItem = (IVsaCodeItem)eng.Items.CreateItem(
"wrap", VsaItemType.Code, VsaItemFlag.None);
codeItem.SourceText = "import System;" +
"System.Console.WriteLine(\"Executing code as a function...\");" +
"WrapperFunc();";
if (!eng.Compile())
return;
eng.Run();
System.Console.WriteLine("Evaluating code as a function...");
Eval.JScriptEvaluate("WrapperFunc();", eng);
System.Console.WriteLine("Evaluating code directly...");
Eval.JScriptEvaluate(code, eng);
Console.WriteLine("Done");
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
-----------------------
Posted by a user from .NET 247 (
http://www.dotnet247.com/)
<Id>XbY2l/UcXUWT2mmd+7r+fQ==</Id>
Global objects get lost during JScript evaluations -
06-09-2004
, 02:23 PM
Linear Mode
