You can transfer integer data from a C# listbox by using the Items.Add method of the listbox. This method accepts any object, including integers.

For example, you can add a series of integers to a listbox like this:

listBox1.Items.Add(1);
listBox1.Items.Add(2);
listBox1.Items.Add(3);
listBox1.Items.Add(4);

You can then retrieve the integer data from the listbox by using the Items.IndexOf method. This method returns the index of the specified object in the listbox.

For example, you can retrieve the integer data from the listbox like this:

int value1 = (int)listBox1.Items.IndexOf(1);
int value2 = (int)listBox1.Items.IndexOf(2);
int value3 = (int)listBox1.Items.IndexOf(3);
int value4 = (int)listBox1.Items.IndexOf(4);