private Expression ConvertIfNeeded(Expression expression, Type type)
{
if (expression.Type != type)
{
return(Expression.Dynamic(
OldConvertToAction.Make(Binder, type, ConversionResultKind.ExplicitCast),
type,
_rule.Context,
expression
));
}
return(expression);
}
/// <summary>
/// Helper that checkes both types to see if either one defines the specified conversion
/// method.
/// </summary>
private MetaObject TryOneConversion(ConversionResultKind kind, Type toType, Type type, Type fromType, string methodName, bool isImplicit, Restrictions restrictions, MetaObject arg)
{
OldConvertToAction action = OldConvertToAction.Make(this, toType, kind);
MemberGroup conversions = GetMember(action, fromType, methodName);
MetaObject res = TryUserDefinedConversion(kind, toType, type, conversions, isImplicit, restrictions, arg);
if (res != null)
{
return(res);
}
// then on the type we're trying to convert to
conversions = GetMember(action, toType, methodName);
return(TryUserDefinedConversion(kind, toType, type, conversions, isImplicit, restrictions, arg));
}
/// <summary>
/// Converts the provided expression to the given type. The expression is safe to evaluate multiple times.
/// </summary>
public virtual Expression ConvertExpression(Expression expr, Type toType, ConversionResultKind kind, Expression context)
{
ContractUtils.RequiresNotNull(expr, "expr");
ContractUtils.RequiresNotNull(toType, "toType");
Type exprType = expr.Type;
if (toType == typeof(object))
{
if (exprType.IsValueType)
{
return(Expression.Convert(expr, toType));
}
else
{
return(expr);
}
}
if (toType.IsAssignableFrom(exprType))
{
return(expr);
}
Type visType = CompilerHelpers.GetVisibleType(toType);
Expression[] args;
if (context != null)
{
args = new Expression[] { context, expr };
}
else
{
args = new Expression[] { expr };
}
return(Expression.Dynamic(
OldConvertToAction.Make(this, visType, kind),
visType,
args
));
}
