Object reference not set to an instance of an object.

ankit r

Hello everyone and thanks in advance.
I am getting an error " Object reference not set to an instance of an object." when I try to add an item to a integer list of class "FreeHoursClass" which has a public list "FreeHoursList".

This is my code.

public class FreeHoursClass

{

public List FreeHoursList = new List();

}

private void button1_Click(object sender, EventArgs e)

{

FreeHoursClass[] ff = new FreeHoursClass[30];

ff[5].FreeHoursList.Add(9);

MessageBox.Show(ff[5].FreeHoursList[0].ToString());

}

3 Replies

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Vulpes14y ago
I'd use a loop:

FreeHoursClass[] ff = new FreeHoursClass[30];
for(int i = 0; i < 30; i++) ff[i] = new FreeHoursClass();
ankit r14y ago
Thanks a lot .It worked but do I have to manually do this for all 30 objects.?ff[1],ff[2]....ff[29]
Vulpes14y ago
The problem is that all the elements of the 'ff' array are null by default.

At the very least, you need to set ff[5] to refer to a new FreeHoursClass object:

FreeHoursClass[] ff = new FreeHoursClass[30];
ff[5] = new FreeHoursClass();
ff[5].FreeHoursList.Add(9);
Console.WriteLine(ff[5].FreeHoursList[0].ToString());