windowsform, checkbox, button clicks

Two immediate options Change the order of the if statements so they are in the order you prefer them to be checked. or better, test the state of all checkboxes in each if statement; that is, don’t just test if some are checked and assume the rest are unchecked — test the unchecked checkboxes as … Read more

Error message in calculator code

I tested the following code and it works fine. Like the comments have said you will get this error if you have not yet created an element with the name txtDisplay. More code would be helpful so I can edit my answer accordingly. public partial class Form1 : Form { public Form1() { InitializeComponent(); } … Read more