Question

I trying to emit dynamic method that sets fields of class by some values and when type of regular field is struct I want to set field with new struct like this: var myStruct = new SomeStruct( );.

But I can’t to find default constructor of that struct.

var type        = valueForField.GetType     ( );

if( type.IsValueType && !type.IsPrimitive && !type.IsEnum )
{
    emit
        .ldarg_0
        .newobj     ( type.GetConstructor( Type.EmptyTypes ) )
        .stfld      ( field );

    continue;
}

It fails at line .newobj ( type.GetConstructor( Type.EmptyTypes ) ) because of passing null to newobj function

Can anybody tell me how to emit new structure creation through it default constructor?

Answer 1

Use initobj

.ldarg_0
.ldflda (field)
.initobj (type)

From msdn:

Value types are not usually created using newobj. They are usually allocated either as arguments or local variables, using newarr (for zero-based, one-dimensional arrays), or as fields of objects. Once allocated, they are initialized using Initobj.