c# - Searching each property value of an IQueryable collection of T against the value of a search query. How do I test for NOT NULL and CONTAINS together? -

i trying search each property value of iqueryable collection of t against value of search query. have following function , know how test not null , contains together?

private expression<func<t, bool>> propertysearch {     {      // object passed lambda expression      parameterexpression instance = expression.parameter(typeof(t), "val");      expression whereexpr = expression.constant(true); // default val => true       var _properties = typeof(t).getproperties();      foreach (var prop in _properties)      {         var query = _httprequest["query"].tolower();         var property = expression.property(instance, prop);         var tostringcall = expression.call(expression.call(             property,             "tostring",              new type[0]),              typeof(string).getmethod("tolower", new type[0]));         whereexpr = expression.and(whereexpr,              expression.call(tostringcall, typeof(string).getmethod("contains"),              expression.constant(query)));      }      return expression.lambda<func<t, bool>>(whereexpr, instance); }} 

i have created search extensions nuget package performs type of check. example following.

note, without ide may have errors

/* *** start: these can made private reaonly fields ***/ var comparisonexpr = expression.constant(stringcomparison.ordinalignorecase); var zeroexpression = expression.constant(0) var nullexpression = expression.constant(null) methodinfo indexofmethod = typeof(string).getmethod("indexof", new[] { typeof(string), typeof(stringcomparison) });   /* *** end ***/  expression finalexpression = null parameterexpression instance = expression.parameter(typeof(t), "val"); var _properties = typeof(t).getproperties(); var query = _httprequest["query"].tolower(); var queryexpr = expression.constant(query);  foreach (var prop in _properties) {     //get property     var propertyexpr = expression.property(instance, prop);     //get property string     var propstringexpr = expression.call(property, "tostring", new type[0]);     //perform indexof call     var indexofexpr = expression.call(propstringexpr,                                         indexofmethod,                                         queryexpr,                                         comparisonexpr);      // check index of greater or equal 0     var containsexpr = expression.greaterthanorequal(containsexpr, zeroexpression);      if(finalexpression == null)     {         finalexpression = containsexp;     }     else     {         finalexpression = expression.andalso(containsexpr);     } }  return expression.lambda<func<t, bool>>(finalexpression, instance); 

i've removed need tolower() , instead used indexof string comparison type

if want see how have achieved similar functionality, take @ ninjanye.searchextensions on github

https://github.com/ninjanye/searchextensions

if wanted search collection of iqueryable use ninjanye.searchextensions follows

string query = _httprequest["query"]; var result = data.searchall().containing(query); 

this search string properties (not properties have above) , return any property mathes search term.

hope helps