YGMapper 3.0.0

YGMapper

A simple object mapper for .NET that maps one DTO to another DTO where the types may or may not be identical.
Also supports mapping DataTable to List<T> and vice versa.
Supports .NET 8 and up.

Installation

Include this package in your project file:

xml <PackageReference Include="YGMapper" Version="3.0.0" />

Usage

Map all matching fields

MapObjects mo1 = new MapObjects();   
var result = mo1.Map<Entity2>(entity1);   

Map with included fields only

MapObjects mo2 = new MapObjects(new string[] { "Name", "EmailAddress" }, null);   
var result2 = mo2.Map<Entity2>(entity1);  

Map with excluded fields

MapObjects mo3 = new MapObjects(null, new string[] { "EmailAddress" });   
var result3 = mo3.Map<Entity2>(entity1);   

Mapping into an existing entity

Entity2 e2 = new Entity2()  
{  
     Entity2Id = 1,  
     Name = "Butter",  
     EmailAddress = "butter@butter.com"  
};  

MapObjects mo6 = new MapObjects(null, new string[] { "Name", "EmailAddress", "Entity2Id" });  
var result6  = mo6.Map<Entity2>(entity1, ref e2);  

Mapping DataTable to List<T>

MapObjects modb = new MapObjects();
List<ViolationEntity> violationEntities = modb.Map<ViolationEntity>(ds.Tables[0]);

Mapping List<T> to DataTable

MapObjects mo0 = new MapObjects();
DataTable dt = mo0.ToDataTable<Entity3>(entity1.Projects);

Output

The Map<T>(object source) method returns:

Tuple<bool, string, T>

Item1 → Success flag
Item2 → Status / error message
Item3 → Mapped destination object

The overload Map<T>(object source, ref T destination) returns:

Tuple<bool, string>

Examples

Test project is provided in the solution to illustrate how to map a DTO, with included or excluded field names.

Output:

The output is Tuple<bool,string,T> , where Item1 represents whether or not the function has executed successfully, Item2 states the success or error message, and Item3 is the output DTO where the source object is mapped to.

Overload output is Tuple<bool,string>, where the destination object is passed as a ref object to Map function

Dependencies

none

Release Notes 3.0.0:

Breaking: Mapping correctness & safety overhaul

✅ Fixed nullable type mapping (int → int?, DateTime → DateTime?)

✅ Added safe type conversion during mapping

✅ Fixed include/exclude filter logic

✅ Prevented mapping into read-only properties

✅ Improved error diagnostics for mapping failures

✅ Normalized DataTable null handling

⚠️ This release includes behavioral changes to mapping logic and is a breaking change for consumers relying on previous implicit behavior.

If you rely on exact 2.x mapping semantics, stay on 2.3.x. v3.x prioritizes correctness, null safety, and explicit type conversion.

Contributing

This project was built with a mix of human experience and AI-assisted refactoring.
PRs and improvements are welcome.

License

This project is licensed under the MIT License(LICENSE).