dosent work

hi community i wrote this script but it dosent update the text in the grid buttons do you have any ideas why this could happen? heres the code:

using UnityEngine; using System.Collections; using System.Collections.Generic;

public class TutorialInventar : MonoBehaviour {

public Rect [] gridRects= new Rect[50];

public int countRects=0;

Dictionary items = new Dictionary();

public string[] showNamesInGrid= new string[50];

int countItems=0;

void AddItems(){

items.Add("schwert","Schwert"); items.Add ("schild","Schild");

}

void OnGUI(){

for( int y=0; y<10; y++){ for(int x =0; x<5; x++){

 if(countRects<49){
 

countRects++;

}

gridRects[countRects]= new Rect(0+60*x,0+60*y,60,60);

GUI.Button (new Rect(gridRects[countRects]),showNamesInGrid[countRects]);

} }

if(GUI.Button (new Rect(300,300,60,60),"schwert")){

countItems++; showNamesInGrid[countItems]=items["schwert"];

} }

void Start(){

AddItems ();

}

}