getting error pixelInset when converted script from js to c#

Unity Engine
1

getting error pixelInset when converted script from js to c#

using UnityEngine;
using System.Collections;

public class MYCLASSNAME : MonoBehaviour {

 

private bool  yPositionFromTop = true;
private bool  xPositionFromRight = false;
public Vector2 buttonPosition;
public float buttonSize = 1.0f;
public GUITexture getGuiTexture;

void  Start (){
	getGuiTexture = GetComponent<GUITexture>();
	transform.position = Vector3.zero;
}

void  Update (){
	if(xPositionFromRight){
		guiTexture.pixelInset.x = Screen.width - buttonPosition.x - guiTexture.texture.width * .5f * buttonSize;
	}
	else{
		guiTexture.pixelInset.x = buttonPosition.x - guiTexture.texture.width * .5f * buttonSize;
	}
	if(yPositionFromTop){
		guiTexture.pixelInset.y = Screen.height - buttonPosition.y - guiTexture.texture.height * .5f * buttonSize;
	}
	else{
		guiTexture.pixelInset.y = buttonPosition.y - guiTexture.texture.height * .5f * buttonSize;
	}
	guiTexture.pixelInset.width = guiTexture.texture.width * buttonSize;
	guiTexture.pixelInset.height = guiTexture.texture.height * buttonSize;
}

}

error message is:
Error Cannot modify a value type return value of UnityEngine.GUITexture.pixelInset'. Consider storing the value in a temporary variable)(1): skipped because it was sent more than once in 0.10 seconds** **Cannot modify a value type return value of UnityEngine.GUITexture.pixelInset’. Consider storing the value in a temporary variable

2

guiTexture.pixelInset = new Rect(x,y,width,height);