Access variable by string name?

Let's say I have a variable named myVar.

I want to call it using the string "myVar". Other than setting up hashtables ahead of time, does anyone know a way to do this?

Is there a way to cast/convert "myVar" to myVar?

 

There sure is, using our old friend Reflection. Try the following:

Code (csharp):

1. public int myVar = 42;
2.  
3. void OnGUI () {
4.     if (GUILayout.Button("Output Variable Value")) {
5.         int newVar = (int)this.GetType().GetField("myVar").GetValue(this);
6.         Debug.Log("Variable value: " + newVar);
7.     }
8. }

If you want to access a variable in another object, simple change this to a reference to that object.

 

Thanks! Do you know the jscript equivalent?

 

Sure, there's just a few minor syntax differences.

Code (csharp):

1. var myVar : int = 42;
2.  
3. function OnGUI () {
4.     if (GUILayout.Button("Output Variable Value")) {
5.         var newVar : int = this.GetType().GetField("myVar").GetValue(this);
6.         Debug.Log("Variable value: " + newVar);
7.     }
8. }

 

Hmm... I'm getting the following error:

Code (csharp):

1. NullReferenceException: Object reference not set to an instance of an object

 

Never mind, it's working now.

Thanks again!

 

Sorry for bumping this old thread but could anyone tell me how tonyd actually corrected the nullreference error ?

 

He probably initialized the object to a value (string myVar = "some data")

... But you should probably make a new thread instead of necroing one from four years ago.

 

Sorry, is it too late now ?

I am trying to call a quaternion by using a bunch of string's value to recreate the quaternion variable's name, is that the correct way to do it ?
i.e.: the quaternion is called RunKey1HipsRot,
the string used are Animation+"Key"+IntKey+Bodypart+Type

 

I think he read the docs.

Reflection in the .NET Framework

 

It's unfortunately a maze for anyone who doesn't know what he should look at.
"using System.Reflection" on top of the script did the trick but i still dont know how i should proceed.
doing this just gives me the same null error at the Quaternion newVar line.

Code (csharp):

1.  
2. string CurrentAnimation = "Run";
3. int Key = 1;
4.  
5. void Start () {
6.  string HipsString = CurrentAnimation+"Key"+Key+"HipsRot";
7.  Quaternion newVar = (Quaternion)this.GetType().GetField("HipsString").GetValue(this);
8. }
9.  

 

1. Is the quaternion you're trying to reference a field, or is it a property?
2. Is the quaternion you're trying to reference a field / property of the class that has the Update() function?

Edit:

Also, your current code is searching for a field named "HipsString", not a field with the name in the HipsString var.

 

It's a field : Quaternion RunKey1HipsRot = Quaternion.Euler(0f, 0f, 340.2343f);
Ill use it in a Slerp, that's why it isn't a vector3.
I dont even do anything besides the Start() yet.

i didn't really know if

Code (csharp):

1. Quaternion newVar = (Quaternion)this.GetType().GetField(CurrentAnimation+"Key"+Key+"HipsRot").GetValue(this);

would work and since i had the same error i thought that it didn't.
Even with that i have the same error.

That's the whole script

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4. using System.Reflection;
5.  
6. public class IKAnimation : MonoBehaviour {
7.  public string CurrentAnimation = "Run";
8.  int Key = 1;
9.  Quaternion RunKey1HipsRot = Quaternion.Euler(0f, 0f, 340.2343f);
10.  void Start () {
11.   Quaternion newVar = (Quaternion)this.GetType().GetField(CurrentAnimation+"Key"+Key+"HipsRot").GetValue(this);
12.   Debug.Log("Variable value: " + newVar);
13.  }
14. }
15.  

Still the same error, thanks alot for at least trying to help me .

 

GetField(String) only finds public fields.

You can use reflection to find private fields, but you'll need to look at the docs for GetField(String, BindingFlags).

 

Thanks a lot, that worked !

 

Hello SmoothP. I see you know how to solve this. Its the same, but i dont get how i have to do it...
i did a post asking almost the same. can you help me please?

http://answers.unity3d.com/question...g-other-variables-values.html#comment-1204626

Thanks a lot!

 

What about if I would like to get a string from an array?
string[] myVar={"a","b","c"};
How do I use this.GetType().GetField thing?

 

I Only Entered Here, to say you: Thanks!!!! For Sharing that Method, it worked me perfectly to asign a Sprite Value from a String name. Me ahorraste muchísimo código! saludos desde República Dominicana.

 

this["myVar"]

have you tried something like this?

 

@yaroslav_ It says, that Type "*file name* (in my case) Inventory.js" does not supports slicing.

 

wow !!!!
this is caviar !!!!

Thanks for the clue