Call a Non-Static Method in Another Project and Namespace

Question

I have two Windows forms applications that belong to separate solutions. I'm trying to call a method from one using the other. I created a class library from the solution I'm trying to access (Sol1) and referenced it in the project I'm running (Sol2) but I'm having difficulty accessing the method.

I found this solution that suggests doing it this way:

string s = string InvokeStringMethod3 ("TheProject", "TheNamespace", "TheClass", "TheMethod");

public static string InvokeStringMethod3(
                        string assemblyName,
                        string namespaceName,
                        string typeName,
                        string methodName)
{
    Type calledType = Type.GetType(namespaceName + "." + typeName + "," + assemblyName);
    String s = (String)calledType.InvokeMember(
                    methodName,
                    BindingFlags.InvokeMethod | BindingFlags.Public | 
                        BindingFlags.Static,
                    null,
                    null,
                    null);
}

When I run it, I get a NullReferenceException where calledType is null. According to the comments, this will only work on static methods but the method I'd trying to call is public void.

Is there a way to modify this to work for a non-static method? Or should this be done another way? I'm working with C# in Visual Studio 2015, and both projects are .NET.

why don't you just instantiate the class this method belongs to? — guijob, Jul 06 '16 at 18:56
Do you understand what the difference is between a static method and an instance (non-static) method? You need to understand the difference between the two, not just to answer this question, but to learn C#. — 15ee8f99-57ff-4f92-890c-b56153, Jul 06 '16 at 18:57
@EdPlunkett If I understand it correctly (which I might not, I'm new to C#), static stays the same every time you run the program, instance doesn't. — AxxieD, Jul 06 '16 at 19:03
You could also just reference the compiled DLL of the other solution... — Camilo Terevinto, Jul 06 '16 at 19:05
@AxxieD - no, that's not it. You are thinking of constant or readonly which is something different entirely. — Igor, Jul 06 '16 at 19:07
@AxxieD - This is a good write up on the MSDN site that should describe what the differences are with plenty of examples: [Static Classes and Static Class Members](https://msdn.microsoft.com/en-us/library/79b3xss3.aspx) — Igor, Jul 06 '16 at 19:09
Maybe there is a good reason why this method is private, you know encapsulation. I think you should talk with author of class that contains method that you try to call, maybe there is other better way for you to use that API... — csharpfolk, Jul 06 '16 at 19:21
Just by fact the method is private what you want is not possible — Paul Swetz, Jul 06 '16 at 19:22
@PaulSwetz I made a mistake, it's `public void`, not `private`. I corrected it in the question. — AxxieD, Jul 06 '16 at 19:24

score 2 · Accepted Answer · edited Sep 06 '18 at 02:24

2

Create an object of the class and use its function when you have already referenced the solution. No need to to create a method static. Inside solution 2 instantiate your solution 1class.

Sol1.MyClass cls = new Sol1.MyClass();

Then you can use the method.

cls.somemethod();

Static members belong to the class not to the object and Can be used directly by class name.

edited Sep 06 '18 at 02:24

Juan Salvador Portugal

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answered Jul 06 '16 at 19:42

Saket Choubey

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Please elaborate your answer. Down vote for posting an answer like a comment. – ViVi Jul 07 '16 at 03:30
This was exactly what I needed. Thank you! – AxxieD Jul 07 '16 at 18:26

Call a Non-Static Method in Another Project and Namespace

1 Answers1