Dynamic linq query with multiple/unknown criteria

I am looking to implement a system whereby a use that 'build' conditions and then return the resulting data back from the database. At present, there is a stored procedure which generates SQL on the fly and executes it. This is a particular issue that I want to remove.

My problem is coming from the fact that I can have multiple fields within my criteria, and for each of these fields, there could be 1 or more values, with different potential operators.

For example,

from t in Contacts 

where t.Email == "email@domain.com" || t.Email.Contains ("mydomain")

where t.Field1 == "valuewewant"

where t.Field2 != "valuewedontwant"

select t

The field, criteria and operator are stored in the database (and ) and would be some thing like this (based on above);

Email, Equals, "email@domain.com"

Email, Contains, "mydomain" Field1,

Equals, "valuewewant" Field2,

DoesNotEqual, "valuewedontwant"

or

new FieldCriteria

{

FieldName = "Email",

Operator = 1, 

Value = "email@mydomain.com"

}

So using the information that I have, I want to be able to build a query with any number of conditions. I have seen previous links to Dynamic Linq and PredicateBuilder, but am not able to visualise this as a solution to my own problem.

Any suggestions would be appreciated.

Update

Following on from the suggestion about Dynamic Linq, I came up with a very basic solution, using a Single Operator, with 2 Fields and multiple Criteria. A little crude at the moment as coded in LinqPad, but the results are exactly what I wanted;

enum Operator

{

    Equals = 1,

}



class Condition

{

    public string Field { get; set; }

    public Operator Operator { get; set;}

    public string Value { get; set;}

}



void Main()

{

    var conditions = new List<Condition>();



    conditions.Add(new Condition {

        Field = "Email",

        Operator = Operator.Equals,

        Value = "email1@domain.com"

    });



    conditions.Add(new Condition {

        Field = "Email",

        Operator = Operator.Equals,

        Value = "email2@domain.com"

    });



    conditions.Add(new Condition {

        Field = "Field1",

        Operator = Operator.Equals,

        Value = "Chris"

    });



    var statusConditions = "Status = 1";



    var emailConditions = from c in conditions where c.Field == "Email" select c;

    var field1Conditions = from c in conditions where c.Field == "Field1" select c;





    var emailConditionsFormatted = from c in emailConditions select string.Format("Email=\"{0}\"", c.Value);

    var field1ConditionsFormatted = from c in field1Conditions select string.Format("Field1=\"{0}\"", c.Value);



    string[] conditionsArray = emailConditionsFormatted.ToArray();

    var emailConditionsJoined = string.Join("||", conditionsArray);

    Console.WriteLine(String.Format("Formatted Condition For Email: {0}",emailConditionsJoined));



    conditionsArray = field1ConditionsFormatted.ToArray();

    var field1ConditionsJoined = string.Join("||", conditionsArray);

    Console.WriteLine(String.Format("Formatted Condition For Field1: {0}",field1ConditionsJoined));







    IQueryable results = ContactView.Where(statusConditions);



    if (emailConditions != null)

    {

        results = results.Where(emailConditionsJoined);

    }



    if (field1Conditions != null)

    {

        results = results.Where(field1ConditionsJoined);

    }



    results = results.Select("id");



    foreach (int id in results)

    {

        Console.WriteLine(id.ToString());

    }

}

With an SQL generated of;

-- Region Parameters

DECLARE @p0 VarChar(1000) = 'Chris'

DECLARE @p1 VarChar(1000) = 'email1@domain.com'

DECLARE @p2 VarChar(1000) = 'email2@domain.com'

DECLARE @p3 Int = 1

-- EndRegion

SELECT [t0].[id]

FROM [Contacts].[ContactView] AS [t0]

WHERE ([t0].[field1] = @p0) AND (([t0].[email] = @p1) OR ([t0].[email] = @p2)) AND ([t0].[status] = @p3)

And Console Output:

Formatted Condition For Email: Email="email1@domain.com"||Email="email2@domain.com"

Formatted Condition For Field1: Field1="Chris"

Just need clean this up and add the other Operators and it is looking good.

If anyone has any comments on this so far, any input would be appreciated