Set object property using reflection

Question

Is there a way in C  where I can use reflection to set an object property   Ex   MyObject obj   new MyObject    obj Name    Value     I want to set obj Name with reflection  Something like   Reflection SetProperty obj   Name      Value     Is there a way of doing this

User · Answer

You can also do    Type type   target GetType     PropertyInfo prop   type GetProperty  propertyName     prop SetValue  target  propertyValue  null     where target is the object that will have its property set

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Reflection  basically  i e   myObject GetType   GetProperty property  SetValue myObject   Bob   null     or there are libraries to help both in terms of convenience and performance  for example with FastMember   var wrapped   ObjectAccessor Create obj    wrapped property     Bob      which also has the advantage of not needing to know in advance whether it is a field vs a property

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You can try this out when you want to mass-assign properties of an Object from another Object using Property names   public static void Assign this object destination  object source                if  destination is IEnumerable  amp  amp  source is IEnumerable                        var dest enumerator    destination as IEnumerable  GetEnumerator                var src enumerator    source as IEnumerable  GetEnumerator                while  dest enumerator MoveNext    amp  amp  src enumerator MoveNext                    dest enumerator Current Assign src enumerator Current                     else                       var destProperties   destination GetType   GetProperties                foreach  var sourceProperty in source GetType   GetProperties                                  foreach  var destProperty in destProperties                                        if  destProperty Name    sourceProperty Name  amp  amp  destProperty PropertyType IsAssignableFrom sourceProperty PropertyType                                                 destProperty SetValue destination      sourceProperty GetValue source  new object         new object                                 break

User · Answer

Yes  you can use Type InvokeMember     using System Reflection  MyObject obj   new MyObject    obj GetType   InvokeMember  Name       BindingFlags Instance   BindingFlags Public   BindingFlags SetProperty      Type DefaultBinder  obj   Value      This will throw an exception if obj doesn t have a property called Name  or it can t be set   Another approach is to get the metadata for the property  and then set it  This will allow you to check for the existence of the property  and verify that it can be set   using System Reflection  MyObject obj   new MyObject    PropertyInfo prop   obj GetType   GetProperty  Name   BindingFlags Public   BindingFlags Instance   if null    prop  amp  amp  prop CanWrite        prop SetValue obj   Value   null

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Or you could wrap Marc s one liner inside your own extension class   public static class PropertyExtension             public static void SetPropertyValue this object obj  string propName  object value                obj GetType   GetProperty propName  SetValue obj  value  null             and call it like this   myObject SetPropertyValue  myProperty    myValue      For good measure  let s add a method to get a property value   public static object GetPropertyValue this object obj  string propName            return obj GetType   GetProperty propName  GetValue  obj  null

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Use somethings like this    public static class PropertyExtension             public static void SetPropertyValue this object p object  string p propertyName  object value           PropertyInfo property   p object GetType   GetProperty p propertyName       property SetValue p object  Convert ChangeType value  property PropertyType   null            or  public static class PropertyExtension             public static void SetPropertyValue this object p object  string p propertyName  object value           PropertyInfo property   p object GetType   GetProperty p propertyName       Type t   Nullable GetUnderlyingType property PropertyType     property PropertyType      object safeValue    value    null    null   Convert ChangeType value  t        property SetValue p object  safeValue  null

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I have just published a Nuget package that allows setting up not only the first level Properties but also nested properties in the given object in any depth   Here is the package  Sets the value of a property of an object by its path from the root   The object can be a complex object and the property can be multi level deep nested property or it can be a property directly under the root  ObjectWriter will find the property using the property path parameter and update its value  Property path is the appended names of the properties visited from root to the end node property which we want to set  delimited by the delimiter string parameter   Usage   For setting up the properties directly under the object root   Ie  LineItem class has an int property called ItemId  LineItem lineItem   new LineItem     ObjectWriter Set lineItem   ItemId   13  delimiter  null     For setting up nested property multiple levels below the object root   Ie  Invite class has a property called State  which has a property called Invite  of Invite type   which has a property called Recipient  which has a property called Id   To make things even more complex  the State property is not a reference type  it is a struct   Here is how you can set the Id property  to string value of    outlook     at the bottom of the object tree in a single line   Invite invite   new Invite     ObjectWriter Set invite   State Invite Recipient Id    outlook   delimiter

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Based on MarcGravell s suggestion  I have constructed the following static method The method generically assigns all matching properties from source object to target using FastMember   public static void DynamicPropertySet object source  object target                  SOURCE         var src accessor   TypeAccessor Create source GetType             if  src accessor    null                        throw new ApplicationException  Could not create accessor                       var src members   src accessor GetMembers            if  src members    null                        throw new ApplicationException  Could not fetch members                       var src class members   src members Where x   gt  x Type IsClass  amp  amp   x Type IsPrimitive           var src class propNames   src class members Select x   gt  x Name           var src propNames   src members Except src class members  Select x   gt  x Name              TARGET         var trg accessor   TypeAccessor Create target GetType             if  trg accessor    null                        throw new ApplicationException  Could not create accessor                       var trg members   trg accessor GetMembers            if  trg members    null                        throw new ApplicationException  Could not create accessor                       var trg class members   trg members Where x   gt  x Type IsClass  amp  amp   x Type IsPrimitive           var trg class propNames   trg class members Select x   gt  x Name           var trg propNames   trg members Except trg class members  Select x   gt  x Name              var class propNames   trg class propNames Intersect src class propNames           var propNames   trg propNames Intersect src propNames            foreach  var propName in propNames                        trg accessor target  propName    src accessor source  propName                     foreach  var member in class propNames                        var src   src accessor source  member               var trg   trg accessor target  member               if  src    null  amp  amp  trg    null                                DynamicPropertySet src  trg

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You can also access fields using a simillar manner   var obj new MyObject    FieldInfo fi   obj GetType      GetField  Name   BindingFlags NonPublic   BindingFlags Instance   fi SetValue obj value    With reflection everything can be an open book   In my example we are binding to a private instance level field

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Yes  using System Reflection   using System Reflection            string prop    name       PropertyInfo pi   myObject GetType   GetProperty prop       pi SetValue myObject   Bob   null

[c#] Set object property using reflection

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