Question

I have an XML document defined like so

XML File

<TABLE>     <RECORD>         <PAGENUMBER> 1 Of 1</PAGENUMBER>         <OtherFields1>..</OtherFields1>         <OtherFields2>..</OtherFields2>     </RECORD>     <RECORD>         <PAGENUMBER> 1 Of 2</PAGENUMBER>         <OtherFields1>..</OtherFields1>         <OtherFields2>..</OtherFields2>     </RECORD>     <RECORD>         <PAGENUMBER> 2 Of 2</PAGENUMBER>         <OtherFields1>..</OtherFields1>         <OtherFields2>..</OtherFields2>     </RECORD>     <RECORD>         <PAGENUMBER> 1 Of 1</PAGENUMBER>         <OtherFields1>..</OtherFields1>         <OtherFields2>..</OtherFields2>     </RECORD> </TABLE> 

I’m trying to create a dynamic query where i can put a ‘Fieldname’, ‘Operand’, ‘Value’ in a config and LINQ can build a predicate based on it.

Config File

<CLAUSES>     <CLAUSE name='PAGENUMBER' operand='!='>Page 1 Of 1</CLAUSE>     <CLAUSE name='OtherFields1' operand='!='>String.Empty</CLAUSE> </CLAUSES> 

Here is the LINQ i’m using now

LINQ Query

        XDocument jobXML = XDocument.Load(JobFile);          List<ClauseObj> clauses = new List<ClauseObj>();         clauses.Add(new ClauseObj { Field = 'PAGENUMBER', Operand = '!=', Value = ' Page 1 Of 1' });          var q = jobXML.Descendants('RECORD').AsEnumerable();          foreach (var c in clauses)         {             switch (c.Operand)             {                 case '!=':                     q = q.Where(r => r.Element(c.Field).Value != c.Value);                     break;             }         } 

how can i make it read the where clauses ‘dynamically’ and also specify which field names to return?

Answer 1

string clause = 'PAGENUMBER'; string operand = '!='; string value= ' Page 1 Of 1';    var q = from r in jobXML.Descendants('RECORD')                  select new                  {                      PAGENUMBER = (string)r.Element('PAGENUMBER'),                      OtherFields1 = (string)r.Element('OtherFields1')                  }     switch(operand)    {        case '!=':           q = q.Where(r=> r.Element(clause).Value != value);           break;        case 'etc':    }     var list = q.ToList();