如果想在C#編程中解析並運行JavaScript代碼，常見的方式有兩種：
這兩種方式都能達到在C#中執行JavaScript代碼的效果，不過各有利弊。 方法一對程序運行環境有要求，程序只能以x86為目標平台。方法二實際是將JavaScript代碼編譯成為了.NET程序集，對JavaScript代碼有嚴格的格式要求，但是可以在任意平台發布（支持跨平台）。 除此之外，其實還有另一種方法來實現這個功能，兼容x86和x64平台，不過僅限於在Windows下使用。而且對JavaScript代碼沒有嚴格的格式要求。
Microsoft® Windows® Script Interfaces introduce a new way for an application to add scripting and OLE Automation capabilities. With the advent of the interfaces, hosts can call upon disparate scripting engines from multiple sources and vendors to perform scripting between components. The implementation of the script itself—language, syntax, persistent format, execution model, and so on—is left to the script vendor. The designers have taken care to allow hosts that rely on Windows Script to use arbitrary language back ends.
以上是微軟對Windows Script Engines的官方解釋，詳細信息可以參看：Microsoft Windows Script Interfaces - Introduction。簡單的說，Windows Script Engines 提供了一種新的方式，讓我們可以為應用程序添加腳本功能。 所以我們只需要將Windows Script Engines進行包裝即可。
1、直接執行表達式：
Console.WriteLine(ScriptEngine.Eval("jscript", "1+2/3"));
將會輸出：1.66666666666667
2、調用有參數的方法：
using (ScriptEngine engine = new ScriptEngine("jscript"))
{
ParsedScript parsed = engine.Parse("function MyFunc(x){return 1+2+x}");
Console.WriteLine(parsed.CallMethod("MyFunc", 3));
}
將會輸出：6
3、調用可選參數NameItem方法：
using (ScriptEngine engine = new ScriptEngine("jscript"))
{
ParsedScript parsed = engine.Parse("function MyFunc(x){return 1+2+x+My.Num}");
MyItem item = new MyItem();
item.Num = 4;
engine.SetNamedItem("My", item);
Console.WriteLine(parsed.CallMethod("MyFunc", 3));
}
[ComVisible(true)] // Script engines are COM components.
public class MyItem
{
public int Num { get; set; }
}
將會輸出：10
如果宿主服務中安裝有IE9+的浏覽器，那麼我們可以調用更快的JavaScript引擎"chakra"：
using (ScriptEngine engine = new ScriptEngine("{16d51579-a30b-4c8b-a276-0ff4dc41e755}"))
{
// continue with chakra now
}
上面只是部分的調用示例，但是應該可以滿足80%的業務需求。上面的代碼依賴於ScriptEngine類，完整的ScriptEngine.cs代碼如下：
/// <summary>
/// Represents a Windows Script Engine such as JScript, VBScript, etc.
/// </summary>
public sealed class ScriptEngine : IDisposable
{
/// <summary>
/// The name of the function used for simple evaluation.
/// </summary>
public const string MethodName = "EvalMethod";
/// <summary>
/// The default scripting language name.
/// </summary>
public const string DefaultLanguage = JavaScriptLanguage;
/// <summary>
/// The JavaScript or jscript scripting language name.
/// </summary>
public const string JavaScriptLanguage = "javascript";
/// <summary>
/// The javascript or jscript scripting language name.
/// </summary>
public const string VBScriptLanguage = "vbscript";
/// <summary>
/// The chakra javascript engine CLSID. The value is {16d51579-a30b-4c8b-a276-0ff4dc41e755}.
/// </summary>
public const string ChakraClsid = "{16d51579-a30b-4c8b-a276-0ff4dc41e755}";
private IActiveScript _engine;
private IActiveScriptParse32 _parse32;
private IActiveScriptParse64 _parse64;
internal ScriptSite Site;
private Version _version;
private string _name;
[Guid("BB1A2AE1-A4F9-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScript
{
[PreserveSig]
int SetScriptSite(IActiveScriptSite pass);
[PreserveSig]
int GetScriptSite(Guid riid, out IntPtr site);
[PreserveSig]
int SetScriptState(ScriptState state);
[PreserveSig]
int GetScriptState(out ScriptState scriptState);
[PreserveSig]
int Close();
[PreserveSig]
int AddNamedItem(string name, ScriptItem flags);
[PreserveSig]
int AddTypeLib(Guid typeLib, uint major, uint minor, uint flags);
[PreserveSig]
int GetScriptDispatch(string itemName, out IntPtr dispatch);
[PreserveSig]
int GetCurrentScriptThreadID(out uint thread);
[PreserveSig]
int GetScriptThreadID(uint win32ThreadId, out uint thread);
[PreserveSig]
int GetScriptThreadState(uint thread, out ScriptThreadState state);
[PreserveSig]
int InterruptScriptThread(uint thread, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo, uint flags);
[PreserveSig]
int Clone(out IActiveScript script);
}
[Guid("4954E0D0-FBC7-11D1-8410-006008C3FBFC"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptProperty
{
[PreserveSig]
int GetProperty(int dwProperty, IntPtr pvarIndex, out object pvarValue);
[PreserveSig]
int SetProperty(int dwProperty, IntPtr pvarIndex, ref object pvarValue);
}
[Guid("DB01A1E3-A42B-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptSite
{
[PreserveSig]
int GetLCID(out int lcid);
[PreserveSig]
int GetItemInfo(string name, ScriptInfo returnMask, out IntPtr item, IntPtr typeInfo);
[PreserveSig]
int GetDocVersionString(out string version);
[PreserveSig]
int OnScriptTerminate(object result, System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int OnStateChange(ScriptState scriptState);
[PreserveSig]
int OnScriptError(IActiveScriptError scriptError);
[PreserveSig]
int OnEnterScript();
[PreserveSig]
int OnLeaveScript();
}
[Guid("EAE1BA61-A4ED-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptError
{
[PreserveSig]
int GetExceptionInfo(out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int GetSourcePosition(out uint sourceContext, out int lineNumber, out int characterPosition);
[PreserveSig]
int GetSourceLineText(out string sourceLine);
}
[Guid("BB1A2AE2-A4F9-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptParse32
{
[PreserveSig]
int InitNew();
[PreserveSig]
int AddScriptlet(string defaultName, string code, string itemName, string subItemName, string eventName, string delimiter, IntPtr sourceContextCookie, uint startingLineNumber, ScriptText flags, out string name, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int ParseScriptText(string code, string itemName, IntPtr context, string delimiter, int sourceContextCookie, uint startingLineNumber, ScriptText flags, out object result, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
}
[Guid("C7EF7658-E1EE-480E-97EA-D52CB4D76D17"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptParse64
{
[PreserveSig]
int InitNew();
[PreserveSig]
int AddScriptlet(string defaultName, string code, string itemName, string subItemName, string eventName, string delimiter, IntPtr sourceContextCookie, uint startingLineNumber, ScriptText flags, out string name, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int ParseScriptText(string code, string itemName, IntPtr context, string delimiter, long sourceContextCookie, uint startingLineNumber, ScriptText flags, out object result, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
}
[Flags]
private enum ScriptText
{
None = 0,
//DelayExecution = 1,
//IsVisible = 2,
IsExpression = 32,
IsPersistent = 64,
//HostManageSource = 128
}
[Flags]
private enum ScriptInfo
{
//None = 0,
//IUnknown = 1,
ITypeInfo = 2
}
[Flags]
private enum ScriptItem
{
//None = 0,
IsVisible = 2,
IsSource = 4,
//GlobalMembers = 8,
//IsPersistent = 64,
//CodeOnly = 512,
//NoCode = 1024
}
private enum ScriptThreadState
{
//NotInScript = 0,
//Running = 1
}
private enum ScriptState
{
Uninitialized = 0,
Started = 1,
Connected = 2,
Disconnected = 3,
Closed = 4,
Initialized = 5
}
private const int TYPE_E_ELEMENTNOTFOUND = unchecked((int)(0x8002802B));
private const int E_NOTIMPL = -2147467263;
/// <summary>
/// Determines if a script engine with the input name exists.
/// </summary>
/// <param name="language">The language.</param>
/// <returns>true if the engine exists; false otherwise.</returns>
public static Version GetVersion(string language)
{
if (language == null)
throw new ArgumentNullException("language");
Type engine;
Guid clsid;
if (Guid.TryParse(language, out clsid))
{
engine = Type.GetTypeFromCLSID(clsid, false);
}
else
{
engine = Type.GetTypeFromProgID(language, false);
}
if (engine == null)
return null;
IActiveScript scriptEngine = Activator.CreateInstance(engine) as IActiveScript;
if (scriptEngine == null)
return null;
IActiveScriptProperty scriptProperty = scriptEngine as IActiveScriptProperty;
if (scriptProperty == null)
return new Version(1, 0, 0, 0);
int major = GetProperty(scriptProperty, SCRIPTPROP_MAJORVERSION, 0);
int minor = GetProperty(scriptProperty, SCRIPTPROP_MINORVERSION, 0);
int revision = GetProperty(scriptProperty, SCRIPTPROP_BUILDNUMBER, 0);
Version version = new Version(major, minor, Environment.OSVersion.Version.Build, revision);
Marshal.ReleaseComObject(scriptProperty);
Marshal.ReleaseComObject(scriptEngine);
return version;
}
private static T GetProperty<T>(IActiveScriptProperty prop, int index, T defaultValue)
{
object value;
if (prop.GetProperty(index, IntPtr.Zero, out value) != 0)
return defaultValue;
try
{
return (T)Convert.ChangeType(value, typeof(T));
}
catch
{
return defaultValue;
}
}
/// <summary>
/// Initializes a new instance of the <see cref="ScriptEngine"/> class.
/// </summary>
/// <param name="language">The scripting language. Standard Windows Script engines names are 'jscript' or 'vbscript'.</param>
public ScriptEngine(string language)
{
if (language == null)
throw new ArgumentNullException("language");
Type engine;
Guid clsid;
if (Guid.TryParse(language, out clsid))
{
engine = Type.GetTypeFromCLSID(clsid, true);
}
else
{
engine = Type.GetTypeFromProgID(language, true);
}
_engine = Activator.CreateInstance(engine) as IActiveScript;
if (_engine == null)
throw new ArgumentException(language + " is not an Windows Script Engine", "language");
Site = new ScriptSite();
_engine.SetScriptSite(Site);
// support 32-bit & 64-bit process
if (IntPtr.Size == 4)
{
_parse32 = (IActiveScriptParse32)_engine;
_parse32.InitNew();
}
else
{
_parse64 = (IActiveScriptParse64)_engine;
_parse64.InitNew();
}
}
private const int SCRIPTPROP_NAME = 0x00000000;
private const int SCRIPTPROP_MAJORVERSION = 0x00000001;
private const int SCRIPTPROP_MINORVERSION = 0x00000002;
private const int SCRIPTPROP_BUILDNUMBER = 0x00000003;
/// <summary>
/// Gets the engine version.
/// </summary>
/// <value>
/// The version.
/// </value>
public Version Version
{
get
{
if (_version == null)
{
int major = GetProperty(SCRIPTPROP_MAJORVERSION, 0);
int minor = GetProperty(SCRIPTPROP_MINORVERSION, 0);
int revision = GetProperty(SCRIPTPROP_BUILDNUMBER, 0);
_version = new Version(major, minor, Environment.OSVersion.Version.Build, revision);
}
return _version;
}
}
/// <summary>
/// Gets the engine name.
/// </summary>
/// <value>
/// The name.
/// </value>
public string Name
{
get
{
if (_name == null)
{
_name = GetProperty(SCRIPTPROP_NAME, string.Empty);
}
return _name;
}
}
/// <summary>
/// Gets a script engine property.
/// </summary>
/// <typeparam name="T">The expected property type.</typeparam>
/// <param name="index">The property index.</param>
/// <param name="defaultValue">The default value if not found.</param>
/// <returns>The value of the property or the default value.</returns>
public T GetProperty<T>(int index, T defaultValue)
{
object value;
if (!TryGetProperty(index, out value))
return defaultValue;
try
{
return (T)Convert.ChangeType(value, typeof(T));
}
catch
{
return defaultValue;
}
}
/// <summary>
/// Gets a script engine property.
/// </summary>
/// <param name="index">The property index.</param>
/// <param name="value">The value.</param>
/// <returns>true if the property was successfully got; false otherwise.</returns>
public bool TryGetProperty(int index, out object value)
{
value = null;
IActiveScriptProperty property = _engine as IActiveScriptProperty;
if (property == null)
return false;
return property.GetProperty(index, IntPtr.Zero, out value) == 0;
}
/// <summary>
/// Sets a script engine property.
/// </summary>
/// <param name="index">The property index.</param>
/// <param name="value">The value.</param>
/// <returns>true if the property was successfully set; false otherwise.</returns>
public bool SetProperty(int index, object value)
{
IActiveScriptProperty property = _engine as IActiveScriptProperty;
if (property == null)
return false;
return property.SetProperty(index, IntPtr.Zero, ref value) == 0;
}
/// <summary>
/// Adds the name of a root-level item to the scripting engine's name space.
/// </summary>
/// <param name="name">The name. May not be null.</param>
/// <param name="value">The value. It must be a ComVisible object.</param>
public void SetNamedItem(string name, object value)
{
if (name == null)
throw new ArgumentNullException("name");
_engine.AddNamedItem(name, ScriptItem.IsVisible | ScriptItem.IsSource);
Site.NamedItems[name] = value;
}
internal class ScriptSite : IActiveScriptSite
{
internal ScriptException LastException;
internal Dictionary<string, object> NamedItems = new Dictionary<string, object>();
int IActiveScriptSite.GetLCID(out int lcid)
{
lcid = Thread.CurrentThread.CurrentCulture.LCID;
return 0;
}
int IActiveScriptSite.GetItemInfo(string name, ScriptInfo returnMask, out IntPtr item, IntPtr typeInfo)
{
item = IntPtr.Zero;
if ((returnMask & ScriptInfo.ITypeInfo) == ScriptInfo.ITypeInfo)
return E_NOTIMPL;
object value;
if (!NamedItems.TryGetValue(name, out value))
return TYPE_E_ELEMENTNOTFOUND;
item = Marshal.GetIUnknownForObject(value);
return 0;
}
int IActiveScriptSite.GetDocVersionString(out string version)
{
version = null;
return 0;
}
int IActiveScriptSite.OnScriptTerminate(object result, System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo)
{
return 0;
}
int IActiveScriptSite.OnStateChange(ScriptState scriptState)
{
return 0;
}
int IActiveScriptSite.OnScriptError(IActiveScriptError scriptError)
{
string sourceLine = null;
try
{
scriptError.GetSourceLineText(out sourceLine);
}
catch
{
// happens sometimes...
}
uint sourceContext;
int lineNumber;
int characterPosition;
scriptError.GetSourcePosition(out sourceContext, out lineNumber, out characterPosition);
lineNumber++;
characterPosition++;
System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo;
scriptError.GetExceptionInfo(out exceptionInfo);
string message;
if (!string.IsNullOrEmpty(sourceLine))
{
message = "Script exception: {1}. Error number {0} (0x{0:X8}): {2} at line {3}, column {4}. Source line: '{5}'.";
}
else
{
message = "Script exception: {1}. Error number {0} (0x{0:X8}): {2} at line {3}, column {4}.";
}
LastException = new ScriptException(string.Format(message, exceptionInfo.scode, exceptionInfo.bstrSource, exceptionInfo.bstrDescription, lineNumber, characterPosition, sourceLine));
LastException.Column = characterPosition;
LastException.Description = exceptionInfo.bstrDescription;
LastException.Line = lineNumber;
LastException.Number = exceptionInfo.scode;
LastException.Text = sourceLine;
return 0;
}
int IActiveScriptSite.OnEnterScript()
{
LastException = null;
return 0;
}
int IActiveScriptSite.OnLeaveScript()
{
return 0;
}
}
/// <summary>
/// Evaluates an expression using the specified language.
/// </summary>
/// <param name="language">The language.</param>
/// <param name="expression">The expression. May not be null.</param>
/// <returns>The result of the evaluation.</returns>
public static object Eval(string language, string expression)
{
return Eval(language, expression, null);
}
/// <summary>
/// Evaluates an expression using the specified language, with an optional array of named items.
/// </summary>
/// <param name="language">The language.</param>
/// <param name="expression">The expression. May not be null.</param>
/// <param name="namedItems">The named items array.</param>
/// <returns>The result of the evaluation.</returns>
public static object Eval(string language, string expression, params KeyValuePair<string, object>[] namedItems)
{
if (language == null)
throw new ArgumentNullException("language");
if (expression == null)
throw new ArgumentNullException("expression");
using (ScriptEngine engine = new ScriptEngine(language))
{
if (namedItems != null)
{
foreach (KeyValuePair<string, object> kvp in namedItems)
{
engine.SetNamedItem(kvp.Key, kvp.Value);
}
}
return engine.Eval(expression);
}
}
/// <summary>
/// Evaluates an expression.
/// </summary>
/// <param name="expression">The expression. May not be null.</param>
/// <returns>The result of the evaluation.</returns>
public object Eval(string expression)
{
if (expression == null)
throw new ArgumentNullException("expression");
return Parse(expression, true);
}
/// <summary>
/// Parses the specified text and returns an object that can be used for evaluation.
/// </summary>
/// <param name="text">The text to parse.</param>
/// <returns>An instance of the ParsedScript class.</returns>
public ParsedScript Parse(string text)
{
if (text == null)
throw new ArgumentNullException("text");
return (ParsedScript)Parse(text, false);
}
private object Parse(string text, bool expression)
{
const string varName = "x___";
object result;
_engine.SetScriptState(ScriptState.Connected);
ScriptText flags = ScriptText.None;
if (expression)
{
flags |= ScriptText.IsExpression;
}
try
{
// immediate expression computation seems to work only for 64-bit
// so hack something for 32-bit...
System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo;
if (_parse32 != null)
{
if (expression)
{
// should work for jscript & vbscript at least...
text = varName + "=" + text;
}
_parse32.ParseScriptText(text, null, IntPtr.Zero, null, 0, 0, flags, out result, out exceptionInfo);
}
else
{
_parse64.ParseScriptText(text, null, IntPtr.Zero, null, 0, 0, flags, out result, out exceptionInfo);
}
}
catch
{
if (Site.LastException != null)
throw Site.LastException;
throw;
}
IntPtr dispatch;
if (expression)
{
// continue our 32-bit hack...
if (_parse32 != null)
{
_engine.GetScriptDispatch(null, out dispatch);
object dp = Marshal.GetObjectForIUnknown(dispatch);
try
{
return dp.GetType().InvokeMember(varName, BindingFlags.GetProperty, null, dp, null);
}
catch
{
if (Site.LastException != null)
throw Site.LastException;
throw;
}
}
return result;
}
_engine.GetScriptDispatch(null, out dispatch);
ParsedScript parsed = new ParsedScript(this, dispatch);
return parsed;
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
if (_parse32 != null)
{
Marshal.ReleaseComObject(_parse32);
_parse32 = null;
}
if (_parse64 != null)
{
Marshal.ReleaseComObject(_parse64);
_parse64 = null;
}
if (_engine != null)
{
Marshal.ReleaseComObject(_engine);
_engine = null;
}
}
}
public sealed class ParsedScript : IDisposable
{
private object _dispatch;
private readonly ScriptEngine _engine;
internal ParsedScript(ScriptEngine engine, IntPtr dispatch)
{
_engine = engine;
_dispatch = Marshal.GetObjectForIUnknown(dispatch);
}
public object CallMethod(string methodName, params object[] arguments)
{
if (_dispatch == null)
throw new InvalidOperationException();
if (methodName == null)
throw new ArgumentNullException("methodName");
try
{
return _dispatch.GetType().InvokeMember(methodName, BindingFlags.InvokeMethod, null, _dispatch, arguments);
}
catch
{
if (_engine.Site.LastException != null)
throw _engine.Site.LastException;
throw;
}
}
void IDisposable.Dispose()
{
if (_dispatch != null)
{
Marshal.ReleaseComObject(_dispatch);
_dispatch = null;
}
}
}
[Serializable]
public class ScriptException : Exception
{
public ScriptException()
: base("Script Exception")
{
}
public ScriptException(string message)
: base(message)
{
}
public ScriptException(Exception innerException)
: base(null, innerException)
{
}
public ScriptException(string message, Exception innerException)
: base(message, innerException)
{
}
protected ScriptException(SerializationInfo info, StreamingContext context)
: base(info, context)
{
}
public string Description { get; internal set; }
public int Line { get; internal set; }
public int Column { get; internal set; }
public int Number { get; internal set; }
public string Text { get; internal set; }
}
提示：該方法同樣可以用來執行VBScript代碼。
