public static Expression BindMethodExpression(MethodCallExpression m, bool allowPolymorphics)
{
if (m.Method.DeclaringType == typeof(ExpressionExtensions) && m.Method.Name == "Evaluate")
{
LambdaExpression lambda = (LambdaExpression)(ExpressionEvaluator.Eval(m.Arguments[0]));
return(Expression.Invoke(lambda, m.Arguments.Skip(1).ToArray()));
}
if (m.Method.HasAttributeInherit <PolymorphicExpansionAttribute>() && !allowPolymorphics)
{
return(null);
}
MethodExpanderAttribute attribute = m.Method.GetCustomAttribute <MethodExpanderAttribute>();
if (attribute != null)
{
if (attribute.ExpanderType.IsGenericTypeDefinition)
{
if (!typeof(GenericMethodExpander).IsAssignableFrom(attribute.ExpanderType))
{
throw new InvalidOperationException("Expansion failed, '{0}' does not implement IMethodExpander or GenericMethodExpander".FormatWith(attribute.ExpanderType.TypeName()));
}
Expression[] args = m.Object == null?m.Arguments.ToArray() : m.Arguments.PreAnd(m.Object).ToArray();
var type = attribute.ExpanderType.MakeGenericType(m.Method.GetGenericArguments());
GenericMethodExpander expander = Activator.CreateInstance(type) as GenericMethodExpander;
return(Expression.Invoke(expander.GenericLambdaExpression, args));
}
else
{
if (!typeof(IMethodExpander).IsAssignableFrom(attribute.ExpanderType))
{
throw new InvalidOperationException("Expansion failed, '{0}' does not implement IMethodExpander or GenericMethodExpander".FormatWith(attribute.ExpanderType.TypeName()));
}
IMethodExpander expander = (IMethodExpander)Activator.CreateInstance(attribute.ExpanderType);
Expression exp = expander.Expand(
m.Object,
m.Arguments.ToArray(),
m.Method);
return(exp);
}
}
LambdaExpression lambdaExpression = GetFieldExpansion(m.Object?.Type, m.Method);
if (lambdaExpression != null)
{
Expression[] args = m.Object == null?m.Arguments.ToArray() : m.Arguments.PreAnd(m.Object).ToArray();
return(Expression.Invoke(lambdaExpression, args));
}
return(null);
}
static async Task <R> Bind <R>(CancellationToken cancellationToken, Expression <Func <R> > bind)
{
var mce = (MethodCallExpression)bind.Body;
IQueryable query = (IQueryable)ExpressionEvaluator.Eval(mce.Arguments.FirstEx()) !;
List <Expression> otherExpressions = mce.Arguments.Skip(1).Select(a => (Expression)ExpressionEvaluator.Eval(a) !).ToList();
var mc2 = Expression.Call(mce.Method, otherExpressions.PreAnd(query.Expression));
var provider = (IQueryProviderAsync)query.Provider;
var value = await provider.ExecuteAsync(mc2, cancellationToken);
return((R)value !);
}