protected override Expression VisitConstant(ConstantExpression node)
{
if (Orm.IsColumnTypeSupported(node.Type))
{
return(new HostParameterExpression(node.Type, node.Value));
}
return(base.VisitConstant(node));
}
/// <summary>
/// Determines whether the given expression can be represented as a column in a select expressionss
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
private bool CanBeColumn(Expression expression)
{
switch (expression.NodeType)
{
case ExpressionType.Add:
case ExpressionType.AddChecked:
case ExpressionType.Subtract:
case ExpressionType.SubtractChecked:
case ExpressionType.Multiply:
case ExpressionType.MultiplyChecked:
case ExpressionType.Divide:
case ExpressionType.Modulo:
case ExpressionType.And:
case ExpressionType.AndAlso:
case ExpressionType.Or:
case ExpressionType.OrElse:
case ExpressionType.ExclusiveOr:
case ExpressionType.OnesComplement:
case ExpressionType.Not:
case ExpressionType.Negate:
case ExpressionType.NegateChecked:
case ExpressionType.UnaryPlus:
case ExpressionType.RightShift:
case ExpressionType.LeftShift:
case ExpressionType.Equal:
case ExpressionType.NotEqual:
case ExpressionType.GreaterThan:
case ExpressionType.GreaterThanOrEqual:
case ExpressionType.LessThan:
case ExpressionType.LessThanOrEqual:
case ExpressionType.Coalesce:
return(true);
case ExpressionType.Constant:
return(Orm.IsColumnTypeSupported(expression.Type));
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
return(true);
case ExpressionType.Conditional:
return(true);
case ExpressionType.Call:
Type declaringType = ((MethodCallExpression)expression).Method.DeclaringType;
if (declaringType == typeof(DateTime) || declaringType == typeof(DateTimeOffset) ||
declaringType == typeof(TimeSpan) || declaringType == typeof(string) ||
declaringType == typeof(decimal) || declaringType == typeof(Math))
{
return(true);
}
goto default;
case ExpressionType.MemberAccess:
Type mDeclaringType = ((MemberExpression)expression).Member.DeclaringType;
if (mDeclaringType == typeof(DateTime) || mDeclaringType == typeof(DateTimeOffset) ||
mDeclaringType == typeof(TimeSpan) || mDeclaringType == typeof(string))
{
return(true);
}
goto default;
default:
return(MustBeColumn(expression));
}
}
