C#•3y ago

Calling a function from a string.

Hey, everyone! I have a timer that will run every 100ms, but I have a list of functions named "f1", all the way up to "f255". I know it sounds impractical to even have all of those functions, but I need them. Anyway, is it possible to have an int++ to call the next function on the list? I want it to do this every time the timer runs: 1: add 1 to the framei int. 2: add the 'f' at the start of the function name, then attach framei after it 3: call the function Expected behavior: 100ms elapsed, f1(); another 100ms elapsed f2(); and so on. Here is an example of the code that doesn't work:

97 Replies

ero•3y ago

why would you possibly need all those functions?

PdawgOP•3y ago

I'm doing a challenge. Run bad apple by manually updating a pixel grid that was created in XAML Each frame is a function, setting pixels that need to be set I told you it's impractical, but I want to do it So is it possible?

ero•3y ago

i feel like this would be better of in one single method honestly

mrphil2105•3y ago

What do these methods do?

ero•3y ago

print a bunch of full size blocks i guess

mrphil2105•3y ago

If they just print the same thing but with a different number then use one method with a parameter

PdawgOP•3y ago

Manually updates each pixel on a pixel grid I haven't actually implemented that yet...since I need this to work first

mrphil2105•3y ago

It is possible to call a function knowing its string, but I am not sure that's the solution here

ero•3y ago

"bad apple" is a song with a music video. people have started playing said music video on weird stuff just like "running DOOM on a calculator" or whatever https://youtu.be/2QiDb_khg44

PdawgOP•3y ago

Yup. Precisely. I have the frontend working, just not the backend How would I do that?

PdawgOP•3y ago

mrphil2105•3y ago

Don't in this case

PdawgOP•3y ago

This is the app btw. That black square is actually made up of many small squares

mrphil2105•3y ago

Calling a function by it's name is only necessary when you have no other option It's slow and kind of "bad code"

PdawgOP•3y ago

Would it still hit that 100ms mark? Like execute within 1ms

ero•3y ago

you probably want like a list or if you must, a dictionary

PdawgOP•3y ago

This is a 3532 frame video or something like that So fun

ero•3y ago

and just access the frame via the index/key

PdawgOP•3y ago

Oh, so like

framei++;
var dict = new Dictionary<int, Action>
    {
        { 1, () => Console.WriteLine("Case 1") }
        { 2, () => Console.WriteLine("Case 2") }
        { 3, () => Console.WriteLine("Case 3") }
    }

framei++;
var dict = new Dictionary<int, Action>
    {
        { 1, () => Console.WriteLine("Case 1") }
        { 2, () => Console.WriteLine("Case 2") }
        { 3, () => Console.WriteLine("Case 3") }
    }

Kinda

ero•3y ago

List<string> frames = new()
{
  "",
  ...
}

List<string> frames = new()
{
  "",
  ...
}

i would just do this? and then do

Console.WriteLine(frames[frame]);

Console.WriteLine(frames[frame]);

PdawgOP•3y ago

Wouldn't going through a list every time the timer hits be slower though?

ero•3y ago

what do you mean?

PdawgOP•3y ago

Than just directly generating the call every time

ero•3y ago

no? it will be so much faster you don't create the list anew every time

PdawgOP•3y ago

Ohh, okay. That makes sense I'll try this out Thank you

pip•3y ago

just for education's sake, the way that you're suggesting(the very bad way) might look something like classObject.GetType().GetMethod("namehere").Invoke(classObject, null); or something

ero•3y ago

private static int _frame;
private static readonly List<string> _frames = new List<string>()
{
  // ...
};

private void Timer_Tick(object sender, EventArgs e)
{
  Console.WriteLine(_frames[_frame++]);
}

private static int _frame;
private static readonly List<string> _frames = new List<string>()
{
  // ...
};

private void Timer_Tick(object sender, EventArgs e)
{
  Console.WriteLine(_frames[_frame++]);
}

it's called reflection, if you still care to look it up you probably don't need the GetType call

typeof(YourClass)
.GetMethod($"f{_frame++}", BindingFlags.Static | BindingFlags.NonPublic)
.Invoke(null, null);

typeof(YourClass)
.GetMethod($"f{_frame++}", BindingFlags.Static | BindingFlags.NonPublic)
.Invoke(null, null);

pip•3y ago

oh cool, that works too

ero•3y ago

but yeah, reflection is incredibly slow, and incredibly bad code

PdawgOP•3y ago

This seems to want C# 9.0

PdawgOP•3y ago

ero•3y ago

and why are you on such an old version?

PdawgOP•3y ago

This is a UWP app That's what the blank app generates

ero•3y ago

hm just don't use target typed new then

pip•3y ago

just put List<string> after it right?

ero•3y ago

it's really not a big deal yeah

PdawgOP•3y ago

Ugh My visual studio install broke again Atleast I can still do this @Ero Would I just add each method as a string?

ero•3y ago

what do you mean?

PdawgOP•3y ago

It doesn't like _frames.Add("f1);

ero•3y ago

i'm not sure what you're referring to you'd put whatever you want to print on that frame

PdawgOP•3y ago

Wait, so this doesn't call another method? This frame can require from 1-256 changes at the same time The methods need to be separate from the list because it would become a jumbled mess

ero•3y ago

you don't even have any of the methods

PdawgOP•3y ago

f1() and f2() for testing

ero•3y ago

this is literally your entire code

PdawgOP•3y ago

Yeah, but the pixels are different for each frame, so it can't be in one single set of code

ero•3y ago

what do you mean? you'd obviously have the pixels be different for each list entry

private static readonly List<string> _frames = new List<string>()
{
  "pixels here",
  "different pixels here",
  "more different pixels"
};

private static readonly List<string> _frames = new List<string>()
{
  "pixels here",
  "different pixels here",
  "more different pixels"
};

PdawgOP•3y ago

Ok. So what I mean then is it won't let me create an entry. I've never used a list before, only arrays and ObservableCollections You just...put that?

ero•3y ago

yes

PdawgOP•3y ago

Does each comma start the next frame?

ero•3y ago

it doesn't "start" anything it's just a different list entry accessible by the list's index you could even use an array, might even be better

PdawgOP•3y ago

By the way, each pixel is set by a color value So example: P12 = Colors.White; P24 = Colors.Black; That would change the color of each pixel Oh okay. Also, it won't let me access the pixel grid from the list

PdawgOP•3y ago

PdawgOP•3y ago

If I put it into an event handler, it's there

PdawgOP•3y ago

PdawgOP•3y ago

In the list, it has no idea what it is @Ero Is there a fix for this? I think it has to do with routing the event(?)

Anchy•3y ago

the issue lies with that the list is expecting a string inside of the initializer however you are trying to assign a brush to a control property inside of that initializer

PdawgOP•3y ago

Yeah, but even trying to get the P(number)s to come up doesn’t work either

Anchy•3y ago

I don't follow?

PdawgOP•3y ago

Basically, each pixel has a name: (example), P1, P2, P3, and so on Each "pixel" is created in xaml But I can't access the pixels from the list Okay, I understand what you're talking about now. Is there a way to fix this? Can I make it expect a control property?

Anchy•3y ago

what exactly are you trying to do

PdawgOP•3y ago

So...I have a grid of "pixels" (rectangles) and I need them to be updated every frame. Bad Apple is two colors, black and white So every frame, some pixels will have a P1.Fill = new SolidColorBrush(Colors.White); or a P1.Fill = new SolidColorBrush(Colors.Black); And I have P1-P256 Each rectangle is one pixel, in a 16x16 grid

Anchy•3y ago

right, so im assuming you will be reading this pixel data in from somewhere

PdawgOP•3y ago

Nope. This is a challenge, I will be manually creating each frame in a function So P1-P256 can be changed each time the timer is called, to whatever value they need to change to I tried earlier, the List thing didn't want to work

Anchy•3y ago

just create a class which defines a frame, then create an ordered list of frames then you can loop through your list of frames and render them based on your frame definition creating 256 functions for each frame is really stupid

PdawgOP•3y ago

Oh I was gonna create 3288 functions to update each pixel at once Lol Though that would be like 800k lines of code (not even joking, I did the math)

Anchy•3y ago

i don't really see the point in doing that

PdawgOP•3y ago

So a loop that counts up to 3288 That makes sense, but the issue lies in the list itself The List does not want to cooperate with me...at all

PdawgOP•3y ago

@Anchy

PdawgOP•3y ago

Here is the issue It doesn't want to let me create a list of pixels for each frame This code is what the person who previously tried to solve this gave me

Anchy•3y ago

public class Pixel
{
   public Color Color { get; set; }
   public int X { get; set; }
   public int Y { get; set; }

   public Pixel(Color color, int x, int y) { this.Color = color; this.X = x; this.Y = y; }
}

public List<Pixel[]> Frames = new List<Pixel[]>
{
  new Pixel[] 
  {
    new Frame(Color.White, 0, 1),
    new Frame(Color.Black, 1, 1)
  }
};

public class Pixel
{
   public Color Color { get; set; }
   public int X { get; set; }
   public int Y { get; set; }

   public Pixel(Color color, int x, int y) { this.Color = color; this.X = x; this.Y = y; }
}

public List<Pixel[]> Frames = new List<Pixel[]>
{
  new Pixel[] 
  {
    new Frame(Color.White, 0, 1),
    new Frame(Color.Black, 1, 1)
  }
};

you could do something like this I suppose, however even this would be really slow

PdawgOP•3y ago

As long as it hits around the +-5ms mark, it'll be okay

Anchy•3y ago

I have no idea what the performance would be like

pip•3y ago

You can thread diff parts of the image youre recoloring but ye idk the performance either

PdawgOP•3y ago

This code seems to be for an actual pixel grid. The "pixels" don't have x and y values. Instead, they are all assigned names

Anchy•3y ago

wat

PdawgOP•3y ago

I know, it's confusing, but the challenge was to create a grid of "pixels" in XAML, and then change their color each frame

PdawgOP•3y ago

PdawgOP•3y ago

Look at this xaml

Anchy•3y ago

oh you mean the Rectangles

PdawgOP•3y ago

This is literally how each pixel out of the 256 are made

Anchy•3y ago

well just replace X and Y with one Rectangle then

PdawgOP•3y ago

Up to 256 of them will need to be changed at once Don't think that'll do

Anchy•3y ago

public class Pixel
{
   public Color Color { get; set; }
   public Rectangle Rect { get; set; }

   public Pixel(Color color, Rectangle rect) { this.Color = color; this.Rect = rect; }
}

public List<Pixel[]> Frames = new List<Pixel[]>
{
  new Pixel[] 
  {
    new Frame(Color.White, P1),
    new Frame(Color.Black, P2)
  }
};

public class Pixel
{
   public Color Color { get; set; }
   public Rectangle Rect { get; set; }

   public Pixel(Color color, Rectangle rect) { this.Color = color; this.Rect = rect; }
}

public List<Pixel[]> Frames = new List<Pixel[]>
{
  new Pixel[] 
  {
    new Frame(Color.White, P1),
    new Frame(Color.Black, P2)
  }
};

again, trying to do this by hand would just be a lot of work for no reason i'd sooner try and read the video file directly and fetch the pixel data before trying to hardcode each frame

PdawgOP•3y ago

This gives the same issue as before

PdawgOP•3y ago

PdawgOP•3y ago

The original video is 320x320 The content area of xaml pixels is 16x16

Anchy•3y ago

oh rename Frame to Pixel originally it was called Frame

PdawgOP•3y ago

I'm talking about these It doesn't like the fact that it's pointing to a rectangle So unless I put 102,400 small rectangles on a page, that's not gonna work

Anchy•3y ago

no it just doesn't like using that reference inside the initializer so instead I would just create the list inside the constructor

PdawgOP•3y ago

Actually, I could do that I have a 16x16 dump of all the frames

PdawgOP•3y ago

Why doesn't discord support bitmaps Anyway, these are pretty good. I could try and "decode" these for each frame

Anchy•3y ago

I think the System.Drawing namespace supports opening bitmaps and you can even loop through all of the pixels

PdawgOP•3y ago

Awesome! Will try it out tomorrow. Thanks!

MasterSubarashii•3y ago

(sorry this is not related to your question but is this WPF? Because it looking quite good)

PdawgOP•3y ago

No, it’s UWP with winui 2.8 lol It would be a lot of work to make a WPF app look this good

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Calling a function from a string.