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What's the difference between new Show(), ShowDialog() and Application.Run() functions? In main (winforms) I saw :

Application.Run(new Form1());

Then, for Form1, I also saw Form1.Show() with description: "Shows the control to the user." For ShowDialog, it said "Shows the form as a modal dialog box".

What does this mean?

What are each of their uses and which is most common?

Gareth Davis
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lost_in_the_source
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    Try them each and find out...that, and look through the documentation for each of the functions. – Servy Dec 31 '13 at 14:55
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    @Servy That comment was even more useless than this one. – orfdorf May 02 '15 at 09:53
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    @Servy I guess you resorted to getting defensive instead of evaluating why your comments are useless. Allow me to explain: It's useless because it answers a question with "just look it up," which is precisely what someone is trying to do when they land on this page and read your comment. – orfdorf May 06 '15 at 08:22
  • @SchizoidSpag How is it useless to know that all of the information is in the documentation, which is going to be readily available to them? The entire question itself is useless, as all it's doing is providing a very poor summary of the already readily available information. It ought not to exist, so that people don't find it when searching for this information; they should simply be looking at the documentation. – Servy May 06 '15 at 13:55
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    @Servy You're right, reading 888 words of documentation and deducing the answer from that is far more efficient than reading the 53-word selected answer. Too bad you didn't put your comment as an answer so the rest of us could show our appreciation for it with upvotes. – orfdorf May 07 '15 at 14:12
  • @SchizoidSpag If by 888 words, you mean the few dozen words at the start of each page, or the few sentences of description for each method in the intellisense documentation. You've probably wasted more time in the comments that you've posted than has been saved by all of the people who have read this answer *combined*, had this answer never existed. It's doing nothing but repeating already readily available information because someone couldn't be bothered to do any work before asking a question, and other people mistakenly encouraged that behavior. – Servy May 07 '15 at 14:16
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    Not an exact duplicate (but the linked question is very useful for anyone wanting the details). I just did a quick google to confirm that the only difference between `Show` and `ShowDialog` is that `Show` is non-modal and `ShowDialog` is non-modal, and this is the top result. – Joey Adams Sep 11 '15 at 13:49

3 Answers3

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The Show function shows the form in a non modal form. This means that you can click on the parent form.

ShowDialog shows the form modally, meaning you cannot go to the parent form

Application.Run() runs the main parent form, and makes that form the main form. Application.Run() is usually found in main.

lost_in_the_source
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  • Show displays the form in a non-modal way.
  • ShowDialog displays the form in a modal way.
  • Application.Run starts a message loop for the application and shows the form as the application's main form
Thomas Levesque
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Application.Run() starts the message loop for the windows forms application. At its most basic level it keeps the process alive until the last form is closed.

http://msdn.microsoft.com/en-us/library/system.windows.forms.application.run(v=vs.110).aspx

Show() method shows a windows form in a non-modal state.

http://msdn.microsoft.com/en-us/library/szcefbbd(v=vs.110).aspx

ShowDialog() method shows a window in a modal state and stops execution of the calling context until a result is returned from the windows form open by the method.

http://msdn.microsoft.com/en-us/library/c7ykbedk(v=vs.110).aspx

Austin
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