Work with the application each time with a different comoboxvalue

[highfly884]

what do you mean bye debug your code properly ? the combobox has the worksheets that are in the excel file and no i'm not opening the wrong file . sorry if i offended you but what you're suggestion is just not logical for me sorry again

[Shaggy Hiker]

what do you mean bye debug your code properly ? the combobox has the worksheets that are in the excel file and no i'm not opening the wrong file . sorry if i offended you but what you're suggestion is just not logical for me sorry again

Put a breakpoint on the line that causes the exception, or a line just before that. Run until the breakpoint is reached. At that point, you can see all the values in all the objects on that line. Without breakpoints, you are just guessing. With breakpoints, you can see what the computer sees.

Once you find what is Nothing, then you can look earlier to where you thought the variable was set. Putting a breakpoint there, you will be able to see whether or not it really IS set there, and might also see why it is Nothing. You WILL see that it is being set to Nothing, or else you will find out that it is not being set where you thought it was being set.

[highfly884]

thank you for your suggestion but i don't know how to insert a break point. im new to vb.net and working on a really complicated app so i didn't have the time to look on the basics of vb.net . thank you for your suggestion i will look on the internet how do we insert breakpoints