Change Color keys on a gradient

Hey,
I'm trying to tint the color keys on a gradient startColor on a particle system by code. It doesn't seem to let me.
here is what I'm doing:

Code (CSharp):

1.  
2. ParticleSystem ps = getComponent<ParticleSystem>();
3. var psMain = ps.main;
4. var grad = psMain.startColor.gradient;
5. grad.colorKeys[0].color = Color.blue;
6.                  
7. psMain.startColor = grad;
8.  

So this just does nothing at all. But if I create a new empty Gradient and assign it the same way it works.
I just don't want to create a new gradient and copy every keys every time I want to change the color of one key.

Is there a way to do this?

(Unity 5.5)
Thanks!

 

Ok, I had to use SetKeys() on the gradient to update the keys

 

Code (CSharp):

1.         List<GradientColorKey> keys = m_Gradient.colorKeys.ToList();
2.  
3.         keys[0] = new GradientColorKey(NewColor, m_Gradient.colorKeys[0].time);
4.         keys[m_Gradient.colorKeys.Length - 1] = new GradientColorKey(NewColor, m_Gradient.colorKeys[m_Gradient.colorKeys.Length - 1].time);
5.      
6.         m_Gradient.SetKeys(keys.ToArray(), m_Gradient.alphaKeys);

If someone is still looking for a solution, this is how I changed the first and last keys of a gradient. Perhaps it can be of some help!

 

This:

Code (CSharp):

1. keys[m_Gradient.colorKeys.Length - 1] =...

really should be

Code (CSharp):

1. keys[keys.Count - 1] =...

Note that "colorKeys" is a property that is calling a native method. This does create a new array each time it is read since the actual keys have to be copied from the native side into managed memory. I haven't really tried it, but I don't think you have to use SetKeys at all, especially when you just want to change the color keys. The colorKeys property does have a setter as well. So you can simply do

Code (CSharp):

1. GradientColorKey[] keys = m_Gradient.colorKeys;
2. keys[0].color = NewColor;
3. keys[keys.Length - 1].color = NewColor;
4. m_Gradient.colorKeys = keys;

Note: changing the "color" of a GradientColorKey directly only works when using an array. When using a List it would not work because GradientColorKey is a struct and a List uses an indexer (get and set methods) to access the elements of the list. Therefore you get a local copy of the key and changing that won't affect the actual element in the list. This does work with an array though. If you really need / want to use a List (only if you need to insert or remove keys) you would could use the GradientColorKey constructor to essentially replace the whole key, or do the same thing, read the key into a local variable, change the color and assign the key back to the same element. This would have the same effect.

 

For anyone trying this, this will not work unfortunately. I will post my solution as an edit as soon I figure it out.