DynamicFilter.Sql

A Fast and efficient dotnet library to dynamically generate compiled lambda expressions from sql style filters.

Installation

DynamicFilter.Sql package can be install via Nuget

dotnet add package DynamicFilter.Sql

Usage/Examples

The Compile function takes a generic parameter that is used to determine the entity fields. This could be a user defined class or it could be a Dictionary<string, object> type.

User defined class

With a user defined class, the field names within the filter expression have to match the property names defined within the class. This is resolved at compile time.

var myfilter = FilterExpression.Compile<User>("(Age > 10) and (Name like 'Alice%' or Name like 'Bob%')");

//Evaluate a single object
bool match = myFilter(new User {Age = 15, Name="Alice Wonderland"})

//Filter a collection
var names = users.Where(myfilter).Select(u => u.Name);

Dictionary

var dict = new Dictionary<string, object> {
                {"Name" , "Alice"},
                {"Age" , 12},
            };

var filter = FilterExpression.Compile<Dictionary<string, object>>("(Age > 10) and (Name like 'Alice%' or Name like 'Bob%')");

var match = filter(dict); //returns true

Features

• Compile to .NET IL code.
• Support Sql Comparison operations
  • =, <, >, <=, >=
  • like, not like
  • in, not in
  • is null, is not null
• Dictionary and User objects

Use cases

• Dynamically generate code to filter objects in memory
• Filter a stream of data with a multiple criteria
• User Preferences/Filters that could be potentially saved/loaded from a File/Database.

Authors

• @prakashrx