NSDictionary always shows null

I am having problem initializing nsdictionary and adding it to array. I tried two appoaches but failed in both. My dictionary is always null.

Appoach1:

NSMutableDictionary *Data =[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"1",@"State_Name",@"2",@"Name",@"3",@"Address",@"4",@"Ph", nil];// initialized in viewdidload


-(void)find:(NSInteger)Item{


        switch (Item) {
        case 0:

            [Data setValue:string forKey:@"State_Name"];
            break;
        case 1:
            [Data setValue:string forKey:@"Name"];
            break;
        case 2:
            [Data setValue:string f开发者_StackOverflow中文版orKey:@"TAddress"];
            break;
        case 3:
            [Data setValue:string forKey:@"Ph"];
            break;
        default:
            break;
    }         
}

Approach2:

NSMutableDictionary *Data =[[NSMutableDictionary alloc] initWithObjectsAndKeys:str1,@"State_Name",str2,@"Name",str3,@"Address",str4,@"Ph", nil];

Could any one tell whats wrong with this code. Am I using nsdictionary's in a wrong way?

Thanks

I executed your code What change you have to do is:- in your .h file write:-

NSMutableDictionary *Data;

in your .m file write:-

Data =[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"1",@"State_Name",@"2",@"Name",@"3",@"Address",@"4",@"Ph", nil];// initialized in viewdidload

Code looks correct. My guess is string is nil. setValue:forKey: allows nil (in turn removes existing object).
try setObject:forKey: , it will raise exception if value(string) is nil or check if string is nil ...

To your first approach: What exactly is spposed to be your key and what your value in the initialiser? It seems to me you mixed up the order.

Besides that : you put strings into the dictionary but refere to a nsinteger in your switch. Are you doing a conversion somewhere in between ?