C#•16mo ago

❔ Class with Func<> and class initializers

If I define a class with members to be passed to known create type functions how do I set the Func<> member to the known function? For example,

public class Known
{
     public string param1;
     public string param2;
     public IRet myObj;
     public Func<string, string, IRet> Create;
}

Dictionay<string, Known> myData = new Dictionary<string, Known>()
{
     {
          "one",                                       // dictionary key
          {
               "abc",                                  // func parameters
               "xyz",
               null,                                   // func returrn value

               CreateFunc,                             // PROBLEM HERE?
          }
     }
};


public static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new IRet(param1, param2);
     return iret;
}

public class Known
{
     public string param1;
     public string param2;
     public IRet myObj;
     public Func<string, string, IRet> Create;
}

Dictionay<string, Known> myData = new Dictionary<string, Known>()
{
     {
          "one",                                       // dictionary key
          {
               "abc",                                  // func parameters
               "xyz",
               null,                                   // func returrn value

               CreateFunc,                             // PROBLEM HERE?
          }
     }
};


public static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new IRet(param1, param2);
     return iret;
}

Thank you in advance.

50 Replies

Angius•16mo ago

Besides public fields, the code seems fine What is the PROBLEM HERE??

r2d25551OP•16mo ago

Thank you for the reponse. Let me look at it. . . Sorry, around this expression the compiler is compainong about :

error CS1525: Invalid expression term '{'
error CS1003: Syntax error, ',' expected

error CS1525: Invalid expression term '{'
error CS1003: Syntax error, ',' expected

Right at the comma at the end of "one",

Angius•16mo ago

Probably because of the missing new Known or at least a new C# is not Javascript

r2d25551OP•16mo ago

And I just tried adding that too

Angius•16mo ago

To create a new Known it would either need a) a constructor b) properties instead of fields

r2d25551OP•16mo ago

It was complaining so I removed it Adding constructor now . .

Angius•16mo ago

new() {
    Param1 = "abc",
    Param2 = "xyz",
    MyObj = null,
    Create = CreateFunc
}

new() {
    Param1 = "abc",
    Param2 = "xyz",
    MyObj = null,
    Create = CreateFunc
}

would work, if you used properties instead of fields

new (
    "abc",
    "xyz",
    null,
    CreaeFunc
)

new (
    "abc",
    "xyz",
    null,
    CreaeFunc
)

would work, if you had a constructor

r2d25551OP•16mo ago

tried too earlier, let me go back to it.

Angius•16mo ago

The first method didn't work because you have public fields Instead of public properties

Thinker•16mo ago

(new() {...})

MODiX•16mo ago

Angius

REPL Result: Success

class Foo {
    public int Bar { get; set; }
}
new { Bar = 69 }

class Foo {
    public int Bar { get; set; }
}
new { Bar = 69 }

Result: <>f__AnonymousType0#1<int>

{
  "bar": 69
}

{
  "bar": 69
}

Compile: 482.180ms | Execution: 115.355ms | React with ❌ to remove this embed.

Angius•16mo ago

No need for ()

Thinker•16mo ago

That didn't create a Foo tho

Angius•16mo ago

Ah, huh You're right Fixed

r2d25551OP•16mo ago

With new { . . . } now the compiler complains about using null for the return type member:

 error CS0828: Cannot assign '<null>' to anonymous type property

 error CS0828: Cannot assign '<null>' to anonymous type property

Angius•16mo ago

Show code

r2d25551OP•16mo ago

Which makes sense given that is literally an c# interface. I need to replace it with the baseclass. . .

Angius•16mo ago

True, null cannot implement an interface But, also, that field is not nullable either

ero•16mo ago

should be able to be null just fine what definitely won't work is new IRet

MODiX•16mo ago

Angius

REPL Result: Success

public interface IFoo {}
public class Bar {
    public IFoo Foo { get; set; }
}

new Bar { Foo = null }

public interface IFoo {}
public class Bar {
    public IFoo Foo { get; set; }
}

new Bar { Foo = null }

Result: Bar

{
  "foo": null
}

{
  "foo": null
}

Compile: 481.026ms | Execution: 52.361ms | React with ❌ to remove this embed.

Angius•16mo ago

It seems to work, yeah, you're right In that case something else is wrong But since we don't have the updated code... the answer is ¯\_(ツ)_/¯

ero•16mo ago

Cannot assign '<null>' to anonymous type property

seems pretty clear to me

MODiX•16mo ago

ero

REPL Result: Failure

public interface IRet { }

public record Known(
    string Param1,
    string Param2,
    IRet? MyObj,
    Func<string, string, IRet> Create);

Dictionay<string, Known> myData = new()
{
    ["one"] = new(
        "abc",
        "xyz",
        null,
        CreateFunc)
};

static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new(param1, param2); // error here
     return iret;
}

public interface IRet { }

public record Known(
    string Param1,
    string Param2,
    IRet? MyObj,
    Func<string, string, IRet> Create);

Dictionay<string, Known> myData = new()
{
    ["one"] = new(
        "abc",
        "xyz",
        null,
        CreateFunc)
};

static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new(param1, param2); // error here
     return iret;
}

Exception: CompilationErrorException

- The type or namespace name 'Dictionay<,>' could not be found (are you missing a using directive or an assembly reference?)
- Cannot create an instance of the abstract type or interface 'IRet'

- The type or namespace name 'Dictionay<,>' could not be found (are you missing a using directive or an assembly reference?)
- Cannot create an instance of the abstract type or interface 'IRet'

Compile: 687.224ms | Execution: 0.000ms | React with ❌ to remove this embed.

ero•16mo ago

typor

Angius•16mo ago

Cannot create an instance of the abstract type or interface 'IRet' That's a different message

ero•16mo ago

i mean yeah i'm referring to this

Angius•16mo ago

Which... is a different error

r2d25551OP•16mo ago

An abstract class didn't help. But if I understood correctly the interface should work too?

Angius•16mo ago

Just show us your updated code already

r2d25551OP•16mo ago

There is a lot of it. And, more importantly, sensitive. It is painstaking to recreate in Discord,

Angius•16mo ago

Then we're wading in the dark "Doctor, it hurts" "Show me where?" "Me hurty" "Okay, but what hurts?" "Tea didn't help" "???" If there's nothing to work with, well, let's hope Ero and Thinker can help you, because I'm out

ero•16mo ago

it's almost difficult to believe there can possibly be any sensitive data where there isn't even any working code

r2d25551OP•16mo ago

Does this work?

Dictionay<string, Known> myData = new()
{
    ["one"] = new(
        "abc",
        "xyz",
        null,
        CreateFunc)
};

static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new(param1, param2); // error here
     return iret;
}

Dictionay<string, Known> myData = new()
{
    ["one"] = new(
        "abc",
        "xyz",
        null,
        CreateFunc)
};

static IRet CreateFunc(string param1, string param2)
{
     IRet iret = new(param1, param2); // error here
     return iret;
}

ero•16mo ago

i don't know, does it?

Angius•16mo ago

You can't instantiate an interface

r2d25551OP•16mo ago

Added the ?

public IRet? myObj;

public IRet? myObj;

But that didn't help. ? means nullable?

Angius•16mo ago

It does, yes IRet iret = new(param1, param2); You can't instantiate an interface

r2d25551OP•16mo ago

Would the construtor help with (trying now):

error CS0746:   Anonymous type members must be declared with a member assignment, simple name or member access.

error CS0746:   Anonymous type members must be declared with a member assignment, simple name or member access.

Angius•16mo ago

No Instantiating a concrete class would You cannot instantiate an interface You cannot instantiate an abstract class You can only ever instantiate a concrete class

r2d25551OP•16mo ago

As in new Known(. . .)?

Angius•16mo ago

As in

IRet iret = new ClassThatImplementsIRet(param1, param2)

IRet iret = new ClassThatImplementsIRet(param1, param2)

r2d25551OP•16mo ago

I am getting two. . .

error CS1922: Cannot initialize type 'Known' with a collection initializer because it does not implement 'System.Collections.IEnumerable'

error CS1922: Cannot initialize type 'Known' with a collection initializer because it does not implement 'System.Collections.IEnumerable'

Changine frm { to )

Angius•16mo ago

Are you initializing a Known with

{
    "foo",
    "bar",
    null
}

{
    "foo",
    "bar",
    null
}

again...?

r2d25551OP•16mo ago

That was my initial setup . . . since added new Known { . . . } now trying new Know( . . . ) and adding the constructor

Angius•16mo ago

new Known {
    Foo = "bar",
    Baz = 421
}

new Known {
    Foo = "bar",
    Baz = 421
}

will work ONLY if you write your code properly and turn those public fields into public properties

r2d25551OP•16mo ago

Can do that. Let me try now. . .

Angius•16mo ago

For reference, $structure

MODiX•16mo ago

namespace Namespace;

[Attribute]
public class Class
{
  public string PublicField;
  private bool _privateField;
  protected double protectedField;    

  public int PublicProperty { get; set; }

  public Class() {} // Constructor

  public void Method(int parameter)
  {
    var localVariable = parameter; 
  } 
}

namespace Namespace;

[Attribute]
public class Class
{
  public string PublicField;
  private bool _privateField;
  protected double protectedField;    

  public int PublicProperty { get; set; }

  public Class() {} // Constructor

  public void Method(int parameter)
  {
    var localVariable = parameter; 
  } 
}

For C# versions older than 10, see $StructureOld

r2d25551OP•16mo ago

Making changes (a few) be right back . . . thank you all for the help. Thank you. The compile and build worked. I need to test it now. Using as properties did the trick. And I am still using an interface as the base. Continued use and improvements of what I worked on is successful. Thank you all.

Accord•16mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Class with Func<> and class initializers