Table of Contents

Primitives

Converting between primitive types (ie. int, bool, double, decimal) is supported, including when those types are nullable. For all other types, if you can cast types in c#, you can also cast in Mapster.

decimal i = 123.Adapt<decimal>(); //equal to (decimal)123;

Enums

Mapster maps enums to numerics automatically, but it also maps strings to and from enums automatically in a fast manner.
The default Enum.ToString() in .NET is quite slow. The implementation in Mapster is double the speed. Likewise, a fast conversion from strings to enums is also included. If the string is null or empty, the enum will initialize to the first enum value.

In Mapster, flagged enums are also supported.

var e = "Read, Write, Delete".Adapt<FileShare>();
//FileShare.Read | FileShare.Write | FileShare.Delete

For enum to enum with different type, by default, Mapster will map enum by value. You can override to map enum by name by:

TypeAdapterConfig.GlobalSettings.Default
    .EnumMappingStrategy(EnumMappingStrategy.ByName);

Strings

When Mapster maps other types to string, Mapster will use ToString method. And whenever Mapster maps string to the other types, Mapster will use Parse method.

var s = 123.Adapt<string>(); //equal to 123.ToString();
var i = "123".Adapt<int>();  //equal to int.Parse("123");

Collections

This includes mapping among lists, arrays, collections, dictionary including various interfaces: IList<T>, ICollection<T>, IEnumerable<T>, ISet<T>, IDictionary<TKey, TValue> etc...

var list = db.Pocos.ToList();
var target = list.Adapt<IEnumerable<Dto>>();

Mappable Objects

Mapster can map two different objects using the following rules:

  • Source and destination property names are the same. Ex: dest.Name = src.Name
  • Source has get method. Ex: dest.Name = src.GetName()
  • Source property has child object which can flatten to destination. Ex: dest.ContactName = src.Contact.Name or dest.Contact_Name = src.Contact.Name

Example:

class Staff {
    public string Name { get; set; }
    public int GetAge() {
        return (DateTime.Now - this.BirthDate).TotalDays / 365.25;
    }
    public Staff Supervisor { get; set; }
    ...
}

struct StaffDto {
    public string Name { get; set; }
    public int Age { get; set; }
    public string SupervisorName { get; set; }
}

var dto = staff.Adapt<StaffDto>();
//dto.Name = staff.Name, dto.Age = staff.GetAge(), dto.SupervisorName = staff.Supervisor.Name

Mappable Object types are included:

  • POCO classes
  • POCO structs
  • POCO interfaces
  • Dictionary type implement IDictionary<string, T>
  • Record types (either class, struct, and interface)

Example for object to dictionary:

var point = new { X = 2, Y = 3 };
var dict = point.Adapt<Dictionary<string, int>>();
dict["Y"].ShouldBe(3);

Record types

Important

Mapster treats Record type as an immutable type. Only a Nondestructive mutation - creating a new object with modified properties.

var result = source.adapt(data) 
//equal var result = data with { X = source.X.Adapt(), ...}

Features and Limitations:

Note

By default, all C# Records are defined as a record type. Limitations by count of constructors and constructor parameters used in Mapster version 7.4.0 do not apply.

Using default value in constuctor param

If the source type does not contain members that can be used as constructor parameters, then will be used the default values ​​for the parameter type.

Example:


class SourceData
{
   public string MyString {get; set;}
}

record RecordDestination(int myInt, string myString);

var result = source.Adapt<RecordDestination>()

// equal var result = new RecordDestination (default(int),source.myString)

MultyConsturctor Record types

If there is more than one constructor, by default, mapping will be performed on the constructor with the largest number of parameters.

Example:

record MultiCtorRecord
{
    public MultiCtorRecord(int myInt)
    {
        MyInt = myInt;
    }

    public MultiCtorRecord(int myInt, string myString) // This constructor will be used
        : this(myInt) 
    {
        MyString = myString; 
    }

}

Support additional mapping features:

Mapping features v7.4.0 v10.0
Custom constructor mapping - ✅
Ignore - ✅
IgnoreNullValues - ✅
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