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I have a form (Report). In public partial class Form1 I have:-
public Report report;

In Form1_Load I have:-
Report report = new Report();

In button1_Click I have:-
This shows no error until run, when it gives the error "Object reference not set to an instance of an object."
I need to make updates to the form Report from several methods.

What I have tried:

Read everything I can google on passing data between forms, working with multiple forms.
Many Questions Answered at Once — Collaboration between Windows Forms or WPF Windows[^]
appears to be authoritative but I am not advanced enough to understand it fully.
Updated 6-Mar-22 17:47pm

1 solution

The thing you're not understanding is "scope". Since you defined the report variable in the Form1_Load method, it is only visible in that method. You also don't need the "public Report report;" line either.

Move the line that defines the report variable to the Button1_Click method and the error goes away.
Report report = new Report();
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ormonds 7-Mar-22 2:32am    
Thank you. However I also have a number of other methods, each of which needs to update textBox1.text on form report.
Is it possible to make the form and its controls global?
Dave Kreskowiak 7-Mar-22 7:39am    
Then you can keep the "private Report report = new Report();" at the class level. You still do not need the line in Form_Load and remove the line from Button1_Click.

That will make the report variable visible to al methods in your form class.
ormonds 7-Mar-22 7:50am    
Thank you. Now I get it.

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