[RESOLVED] Cant Quit :(

[RobDog888]

What am I doing wrong when trying to .Quit an office app?

...Form1.cs(116): No overload for method 'Quit' takes '0' arguments
'Or
...Form1.cs(116): No overload for method 'Quit' takes '1' arguments
...Form1.cs(116): Argument '1': cannot convert from 'bool' to 'ref object'

'Or
...Form1.cs(116): No overload for method 'Quit' takes '3' arguments
...Form1.cs(116): Argument '1': cannot convert from 'bool' to 'ref object'
...Form1.cs(116): Argument '2': cannot convert from 'int' to 'ref object'
...Form1.cs(116): Argument '3': cannot convert from 'bool' to 'ref object'

None of these work...

oApp.Quit();
oApp.Quit([color=blue]false[/color]);
oApp.Quit([color=blue]false[/color],1,[color=blue]false[/color]);
[color=darkgreen]//Destroy the reference[/color]
oApp = [color=blue]null[/color];

[dynamic_sysop]

depending on how many parameters you need to quit ...
you need to create a ref object of each parameter.
eg:

[COLOR=Blue]object[/COLOR] a = ( [COLOR=Blue]object[/COLOR] ) [COLOR=Blue]true[/COLOR]; [COLOR=Green]///  a [B]bool[/B][/COLOR]
[COLOR=Blue]object[/COLOR] b = ( [COLOR=Blue]object[/COLOR] ) 1; [COLOR=Green]/// an [B]int[/B][/COLOR]
[COLOR=Blue]object[/COLOR] c = ( [COLOR=Blue]object[/COLOR] ) [COLOR=Blue]false[/COLOR];
 
oApp.Quit([COLOR=Blue]ref[/COLOR] a , [COLOR=Blue]ref[/COLOR] b , [COLOR=Blue]ref[/COLOR] c);

[RobDog888]

It worked. Man, VB.NET lets you do it easily with .Quit(False).
I searched MSDN and couldnt find anything on .Quit and C#.

Thanks a million
Hopefully you will settle for 10.

[color=blue]object[/color] a = ([color=blue]object[/color]) [color=blue]false[/color];
[color=blue]object[/color] b = ([color=blue]object[/color]) 1;
oApp.Quit([color=blue]ref[/color] a, [color=blue]ref[/color] b, [color=blue]ref[/color] a);
oApp = [color=blue]null[/color];

Edit: just seen you changed your avatar. Congrats on your new Baby

[RobDog888]

Another question, Why do I have to pass an argument as it wont let me pass nothing? Each argument has a default so like in VB.NET and VB 6 you dont need to specify one.

[jmcilhinney]

Note that the methods you call in Office apps are written in VB and many use optional arguments. There is no support for optional arguments in C# so you ALWAYS have to provide a value for EVERY argument when calling those methods from C#. That's a good reason to use overloading in your own VB code rather than optional parameters. I've made the switch for that very reason.

[RobDog888]

Ah, yes. I remember reading that C# has no optional parameters/arguments. That makes sense now. Thanks for the Tip too.

For more clarification, the a and b object variables are just empty containers of the designated types for filling in the required args, correct?

Edit: Since I have your attention, is there an Option Explicit and Otpion Strict for C#? I couldnt find one.

[jmcilhinney]

is there an Option Explicit and Otpion Strict for C#?

No. Assume that they are both set to On and there is no way to turn them Off, as it should really be in VB.NET as well, or at least have Option strict On by default. Those Options are part of the reason that VB.NET is probably easier for the beginner than C#, but C# enforces good practices more strictly so I think you tend to become a better programmer more quickly in C# as a result. How mystified do people get when they have been using VB.NET for six months or so and then someone suggests that they turn Option Strict On and they suddenly have hundreds of errors?

[RobDog888]

Yup I know what you mean. I always use it On but until I realized that it was On by default in C#, I dont have to worry about it. Thanks.

[dynamic_sysop]

if you use the Type.InvokeMethod of your object, you can often avoid having to specify extra paramters ( it's a way around the Optional items of a method / function )

eg:
take the Webbrowser Control, in C# you must specify the ref objects when navigating

[COLOR=Green]/// if you use the normal method, you pass all the parameters...[/COLOR]
browser.Navigate2("the url" , ref object , ref object , ref object , ref object);

but you can avoid using all the extra bits like this ...

[COLOR=Green]/// to bypass any optional paramters ...[/COLOR]
[COLOR=Blue]object[/COLOR][] args = {"http://google.co.uk"}; [COLOR=Green]/// ignore the extra parameters[/COLOR]
axWebBrowser1.GetType().InvokeMember("Navigate2" , System.Reflection.BindingFlags.InvokeMethod , [COLOR=Blue]null[/COLOR], axWebBrowser1 , args);

btw, thanks for the Congrats

[penagate]

It worked. Man, VB.NET lets you do it easily with .Quit(False).
I searched MSDN and couldnt find anything on .Quit and C#.

Thanks a million
Hopefully you will settle for 10.

[color=blue]object[/color] a = ([color=blue]object[/color]) [color=blue]false[/color];
[color=blue]object[/color] b = ([color=blue]object[/color]) 1;
oApp.Quit([color=blue]ref[/color] a, [color=blue]ref[/color] b, [color=blue]ref[/color] a);
oApp = [color=blue]null[/color];

Edit: just seen you changed your avatar. Congrats on your new Baby

I guess you could do it a bit shorter

oApp.Quit(ref (object) false, ref (object) 1, ref (object) false);
oApp = null;

tedious as it still is.

[RobDog888]

How come if you can do it that shorter way you dont have to explicitly instanciate the object as you dont get an "Object not set to an instance ..." error?

[penagate]

If you cast something to an object, you make an object instance, and you can pass a reference to it without keeping one yourself. So my code is the same as yours without actually storing local references to the newly created objects.

[RobDog888]

I'm still new to C# PG. Could you explain a little more? "(object) false" is casting false to an object varaible type?

[penagate]

Yep that's it. "false" is obviously a Boolean which is a value type. The brackets () in front of a variable is the cast operator. Inside the brackets you specify what type you want to cast to. In this case we are just casting to a generic object. The process here of casting a value type to a reference type (object) containing the value is known as "boxing", and there is a decent page detailing it here. Going the other way is, as you would expect, "unboxing". In VB.NET, I think the one-line version is unachievable, without using an object-typed variable and setting that variable to your value-type variable, due to the lack of a cast operator.

[RobDog888]

Ok, Thanks. Seems C# is reverse from vb.net when it comes to variables. Maybe now my dyslexia will come in handy.

[jmcilhinney]

"CObj(False)" is the VB.NET equivalent of "(object)false" in C#. I doubt that the IL is exactly the same but the effect within your app is the same: a reference-type Object instance containing the boolean value False is created.

[penagate]

I thought C...() were functions, so it would be a little bit different under the hood. Although, the JIT compiler might look for and optimise that.

[jmcilhinney]

I'm quite sure that the IL is different in each case, but using CObj, et al. is not like using most VB.NET functions:

These functions are compiled inline, meaning the conversion code is part of the code that evaluates the expression. Execution is faster because there is no call to a procedure to accomplish the conversion.