cannot access a disposed object in c#

Disposing of object has nothing to do with its accessibility. Actually, objects are not even classified into disposed and non-disposed.

The method <code>Dispose itself has no predefined meaning, except using in the "using" construct, only if this method is written as implementation of IDisposable.Dispose.

The standard purpose of Dispose is 1) cleaning up unmanaged resources, 2) calling IDisposable.Dispose of other objects thus disposing a chain of related objects of some hierarchy of the object model (typical example: System.Windows.Forms.Form); the ultimate purpose of such chain of calls is -- again -- cleaning of associated unmanaged resources.

There can be some other uses of the interface and its implementation, mainly thanks to the "using" construct functionality. For a funny example, see my Tips/Tricks article (and alternative Tips on the same page; they are good): Hourglass Mouse Cursor Always Changes Back to its Original Image. How?[^].

This should explain the purpose of using and the fact it cannot affect accessibility of any object. Maybe, the question was caused to some different unrelated problem which was misinterpreted.

google with keywords

c# dispose

and you will find, that the reason for using Dispose is to clean up some stuff (as SAKryukov explained), and therefor you cannot access a disposed object.

It's meaning that you have closed any form and then the program cannot any access to form which is disposed. If there aren't information you can write that:
...{
[Your Form] f = new [Your Form];
if(f.IsDisposed){
f = new [Your Form];
}
f.Show();
}
else having information write it to any file and Write to it:


System.IO.StreamWriter sw = System.IO.File.CreateText(@"your path\\...\\your file.your file type");
if you don't want to write the information on new line
sw.Write();
else
sw.WriteLine();