Using a referenced C# object in a seperate class/form - c#

I've got a Windows Form program that creates a Config object which contains various configuration variables used by my program.
Within the main form, it contains a button to open a new configuration form, where it passes the Config object as a reference -
FormConfig button = new FormConfig(ref config);
button.ShowDialog();
Now in the FormConfig class, I can access the Config object within the main constructor
public FormConfig(ref Config config)
{
InitializeComponent();
// can access config.xyz OK here
}
However within the new form, I've got a button that calls another function that needs to access the reference Config object, however I'm struggling to find a clean way to do so.
I can create another Config object as part of the FormConfig class, and then copy the referenced Config to it in the main constructor, however then the original config object doesn't get updated.
How can I achieve this?
PS apologies in advance if this is already answered, but my searches have so far failed to find a solution, possibly because I'm not sure what the correct search terms should be.

And the solution thanks to #cmos, is to declare the Config class as static, which negates the need to use any referencing or passing objects between classes/functions -
public static class Config
{
public static bool SettingA = true;
}
Which means I can access and modify the Config object from anywhere within the same namespace with the following code, without needing to have a class instance -
Config.SettingA
Thanks to all those who helped point me in the right direction.

Related

Get right instance of VS2017 for self developed extension

I'm developing a Visual Studio Extension to replace text in the current active .cs file using a custom command that is invoked from the right click context menu in the Code Window.
Accessing the document works so far, but if I start more than one instance of VS2017, then changes which I expect to be done in the new instance are made in the first opened instance.
Is there a possibility to get the right instance to access only the current active Document no matter how many instances are open?
At the moment I get the instance with following code:
dte = (EnvDTE.DTE)System.Runtime.InteropServices.Marshal
.GetActiveObject("VisualStudio.DTE.15.0");
Does anybody have an idea how to solve this?
You need to use in the class of your package (that inherits from the AsyncPackage base class):
EnvDTE.DTE dte = (EnvDTE.DTE) base.GetService(typeof(Microsoft.VisualStudio.Shell.Interop.SDTE));
The code that you were using returns some DTE instance running on your system, not necessarily the one where your extension is hosted.
As Carlos Quintero already said, you should get the DTE Object by using his example.
Lets say your extension name is YourExtension:
In my case, I added a Property in my YourExtension.cs
public EnvDTE.DTE DTEObject { get; set; }
Then in YourExtensionPackage.cs you can get the desired DTEObject right after your package got initialized:
protected override void Initialize ()
{
YourExtension.Initialize (this);
base.Initialize ();
YourExtension.Instance.DTEObject = (EnvDTE.DTE)base.GetService (typeof (Microsoft.VisualStudio.Shell.Interop.SDTE));
}
Now you can work with the DTEObject within your extension and get any Object via GetObject. In My case for example I'm getting the current instance of the VersionControlEx.

Access properties in App.xaml.cs from different project UWP

Like what I said in the title, how can we access the property in App in a different project? I want to access it from normal class like a service. Not in viewmodel. Hope we can do something like Application as App.
Access properties in App.xaml.cs from different project UWP
You may try to use one App.xaml.cs for the two projects. For example, if the second project wants to access App.xaml.cs in the first project without reference the first project, you may consider remove the App.xaml.cs which is belonged to the second project, and Add-ExitingItem to add the App.xaml.cs from the first project. In that case, the two projects will share the same App.xam.cs and then you can directly access the properties as Marian Dolinský mentioned.
Otherwise, the two projects may not be able to communicate with each other directly. If the above method is not suit for you, please detail why you need this feature and we may need to consider other ways without accessing the App.xaml.cs.
Method 1
You could cast Application.Current to App:
App app = (App)Application.Current;
app.YourProperty = something;
Method 2
Create some static property holding the reference of App. In my projects I do it by creating a new property called Current as follows:
// in App.xaml.cs
public static new App Current { get; private set; }
public App()
{
Current = this;
// Another code
}

sharing a static class with a DLL in C# without passing a reference

VS2012 for desktop .net framework 4.5 normal windows forms applications, not WPF
Hello, I tried to search for an answer, but I'm not sure of the correct terminology. I've managed to break my code, and can't understand what I've done wrong. (i didn't think i had changed anything, but ...)
I have a solution which contains 2 projects. The first project is an executable program, and the second is a DLL, which is loaded at run time and used by the first project.
the first project contains a form, and a static class with public static strings in the same namespace. (and some other unconnected classes). specifically:
namespace project1_namespace
{
static class settings
{
public static string some_words = "some words in a string";
}
class dll_callback{
//.. some public methods here
}
dll_callback dllcallback; // instance is initialised in the code (not shown)
Form form;
public partial class frm_splash : Form
{
private void frm_splash_FormClosing(object sender, FormClosingEventArgs e)
{
// this function actually loads the DLL, ensuring its the last step
//... some error checking code removed for brevity
Assembly assembly = Assembly.LoadFrom("c:\dllpath\project2.dll");
Type type_init = assembly.GetType("project2_class");
object init = Activator.CreateInstance(type_init, form, dllcallback);
//... some error checking code removed for brevity
}// end method
}// end form class
}// end namespace
when the form is closing, the method shown above is called which calls the second projects class project2_class constructor.
in project 2, the DLL, there is:
namespace project2_namespace
{
// how did i get this working to reference "settings" class from project 1??
public class project2_class
{
public project2_class(project2_namespace.Form1 form_ref, object callback)
{
settings.some_words = "the words have changed";
//... some more stuff
}
}
}
Now, i was experimenting with some code in an entirely different part of project2, and VS2012 suddenly started refusing to compile stating:
error CS0103: The name 'settings' does not exist in the current context
the standard solution to this appears to be to add a reference to project2, but that would create circular dependencies because project 1 calls 2 as a DLL.
I really honestly don't think i had changed anything relevant to this, but also clearly I have.
looking at it, i cant see how project 2 would have access to a class in project 1 without a reference, but the list of arguments to the project2_class constructor doesn't include one, and I am absolutely positive that it hasn't changed (and I cant change it for backwards compatibility reasons).
would really appreciate help with this, as its been a lot of work to get this working.
as a side note, I've definitely learned my lesson about not using source control. and not making "how this works" comments instead of "what this does" comments.
may dynamic help you? You can not get the setting string at complie time.

App.config multi-project access strategies

My current solution has 3 project with 2 app.config (one for common settings and another for service settings). As of now I'm simply creating static classes to act as a mediator to access values. I do this so I don't have to write ConfigurationManager.AppSettings["SomeKey"] everywhere. This works fine until you want to access an app.config file from a different project.
Here is what I'm currently doing (all properties omitted for brevity).
public class ServiceConfiguration
{
public static readonly string SyncEvery = ConfigurationManager.AppSettings["SyncEveryMinutes"];
}
How can I access an app.config file located in another project? I thought perhaps setting VS to copy the file to the output directory would do the trick however my configuration object is still null.
I can't imaging many good reasons to read another app's configuration in the first place, it just opens a can of worms that isn't worth dealing with.
Expose a class that exposes the project's configured values as properties, and access them from a consuming class.
public class FirstProjectClass
{
public static int SyncEveryMinutes
{
get { return (int)ConfigurationManager.AppSetting["SyncEveryMinutes"] };
}
}
public class SecondProjectClass
{
public void ShowConfigedValue()
{
Console.Writeline("Syncing every {0} minutes", FirstProjectClass.SyncEveryMinutes);
}
}
if you've got complex configuration requirements you can also look into custom configuration sections
ConfigurationManager.OpenExeConfiguration can be helpfull:
http://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager.openexeconfiguration.aspx
Also: what Jason said - it is usually a bad idea.

Accessing HttpApplication.Application variables from a class

I set up various global parameters in Global.asax, as such:
Application["PagePolicies"] = "~/Lab/Policies.aspx";
Application["PageShare"] = "/Share.aspx";
Application["FileSearchQueries"] = Server.MapPath("~/Resources/SearchQueries.xml");
...
I have no problem accessing these variables form .ascx.cs or .aspx.cs file -- ie. files that are part of the Web content. However, I can't seem to access 'Application' from basic class objects (ie. standalone .cs files). I read somewhere to use a slight variations in .cs files, as follows, but it always comes throws an exception when in use:
String file = (String)System.Web.HttpContext.Current.Application["FileSearchQueries"];
While it's true that you can use HttpContext.Current from any class you must still be processing an HTTP request when you call it - otherwise there is no current context. I presume that's the reason you're getting an exception, but posting the actual exception would help clarify matters.
to share your variable across app, and to be able to access it from standalone class, you can use static variable of a class, instead of using HttpApplication variable.
public MyClass{
public static int sharedVar;
}
//and than you can write somwhere in app:
MyClass.sharedVar= 1;
//and in another location:
int localVar = MyClass.sharedVar;

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