public static ParameterExpression[] GetExpressionParameters(Expression expr)
{
var paramsVisitor = new ExtractParamsVisitor();
paramsVisitor.Visit(expr);
return(paramsVisitor.ParamsList.ToArray());
}
public object Eval(string expr, IDictionary <string, object> vars)
{
CompiledExpression compiledExpr;
if (!CachedExpressions.TryGetValue(expr, out compiledExpr))
{
var linqExpr = Parse(expr, vars);
var paramsVisitor = new ExtractParamsVisitor();
paramsVisitor.Visit(linqExpr);
compiledExpr = new CompiledExpression()
{
Parameters = paramsVisitor.ParamsList.ToArray()
};
var lambdaExpr = Expression.Lambda(linqExpr, compiledExpr.Parameters);
compiledExpr.Lambda = lambdaExpr.Compile();
lock (CachedExpressions) {
CachedExpressions[expr] = compiledExpr;
}
}
var valuesList = new List <object>();
foreach (var paramExpr in compiledExpr.Parameters)
{
valuesList.Add(new LambdaParameterWrapper(vars.ContainsKey(paramExpr.Name) ? vars[paramExpr.Name] : null));
}
var lambdaRes = compiledExpr.Lambda.DynamicInvoke(valuesList.ToArray());
if (lambdaRes is LambdaParameterWrapper)
{
lambdaRes = ((LambdaParameterWrapper)lambdaRes).Value;
}
return(lambdaRes);
}
public static ParameterExpression[] GetExpressionParameters(Expression expr) {
var paramsVisitor = new ExtractParamsVisitor();
paramsVisitor.Visit(expr);
return paramsVisitor.ParamsList.ToArray();
}
