Joining multiple where clauses in LINQ as OR instead of AND

Question

Is there anyway to join LINQ where clauses as OR ?

var ints = new [] { 1, 3, 5, 7 };

var query = from i in ints select i;

query = query.Where (q => q ==         


        

Answer 1

Using ExpressionVisitor to help to build the expression base on two expressions with OR/AND relationship. This answer is from Jeffery Zhao's blog.

internal class ParameterReplacer : ExpressionVisitor
{
    public ParameterReplacer(ParameterExpression paramExpr)
    {
        this.ParameterExpression = paramExpr;
    }

    public ParameterExpression ParameterExpression { get; private set; }

    public Expression Replace(Expression expr)
    {
        return this.Visit(expr);
    }

    protected override Expression VisitParameter(ParameterExpression p)
    {
        return this.ParameterExpression;
    }
}

public static Expression> And(this Expression> one, Expression> another)
{
    var candidateExpr = Expression.Parameter(typeof(T), "candidate");
    var parameterReplacer = new ParameterReplacer(candidateExpr);

    var left = parameterReplacer.Replace(one.Body);
    var right = parameterReplacer.Replace(another.Body);
    var body = Expression.And(left, right);

    return Expression.Lambda>(body, candidateExpr);
}

public static Expression> Or(this Expression> one, Expression> another)
{
    var candidateExpr = Expression.Parameter(typeof(T), "candidate");
    var parameterReplacer = new ParameterReplacer(candidateExpr);

    var left = parameterReplacer.Replace(one.Body);
    var right = parameterReplacer.Replace(another.Body);
    var body = Expression.Or(left, right);

    return Expression.Lambda>(body, candidateExpr);
}