将文件路径传递给Main（string [] args）不起作用

Question

I am trying to pass a file path into a C# Console Application but am having problems with the string being incorrect by the time it reaches the console application.

If I run my application from the command line, with a file path parameter:

MyApp "C:\Users\DevDave\Documents\Visual Studio 2012\Projects\MyProject\"

A windows dialogue pops up and informs me that my application has stopped working, and when I click the Debug option, I can see that the result of args[0] is:

C:\\Users\\DevDave\\Documents\\Visual Studio 2012\\Projects\\MyProject"

Note there is still a trailing quote at the end.

If I pass a second argument:

MyApp "C:\Users\DevDave\Documents\Visual Studio 2012\Projects\MyProject\" "any old string"

I get an error again, and after viewing in debug I see that args[0] is:

C:\\Users\\DevDave\\Documents\\Visual Studio 2012\\Projects\\MyProject" any

I am baffled as to why this is happening. My only guess is that the backslashes in the string are causing some kind of escape sequence from the string? Edit : I notice that the same is happening in the string example above! It seems \\" is causing problems here.

I just want to pass in the file path of the current solution directory and am calling my app from a pre-build event using $(SolutionDir), and know that I can get the path of the current solution in other ways. But this is simplest and I am curious as to why it does not work as expected.

Answer 1

Yes, the rules for commandline arguments are a little murky.

The \\ is the escape char and you can use it to escape quotes ( " ). You'll have to escape a backslash but only when it is preceding a quote. So use (note the '\\\\' at the end):

MyApp "C:\Users\DevDave\Documents\Visual Studio 2012\Projects\MyProject\\" 

or, simpler but you'll have to deal with it in C# somehow:

MyApp "C:\Users\DevDave\Documents\Visual Studio 2012\Projects\MyProject" 

Also see this question

Answer 2

That's why it's always better to use / in path

"C:/Users/DevDave/Documents/Visual Studio 2012/Projects/MyProject/" "any old string"

take a look: http://en.wikipedia.org/wiki/Path_(computing) , you can use both \\ and / in path but if you want any shell compatibility I suggest to use /

Answer 3

Anything that comes after MyApp will be the first argument (args[0]). In your case, the first argument is "C:\\Users\\DevDave\\Documents\\Visual Studio 2012\\Projects\\MyProject\\" . Also, the quote at the end of the string seems to happen because \\" means that you want to want to escape the quote and write it as a string. In this case, the quote is not closing the string. That is the reason that your args[0] is the whole thing that comes after MyApp

If you don't want to scape the quote and have a slash behind it, you should do \\\\"

You could try this and tell me what happens:

MyApp "C:\Users\DevDave\Documents\Visual Studio 2012\Projects\MyProject\\"

(look at the double slash)

Hope it helps.

Answer 4

Continuation of Henk's answer, and choose to add a \\ at the end of the path, then:

If you choose to hack the bug by choosing this code in Henk's answer ("simpler but you'll have to deal with it in C# somehow:"), then you should realize some bugs that will occur:

1. args[0] will only be set, even if you pass multiple parameters in. The length of args will be equal to 1. So you have to split args[0] into multiple pieces for your hack.

2. You have to replace any " characters with a \\ if they are at the end of the pieces you split.