I am new to C# and I'm having a little problem with calling a function from the Main() method.
class Program
{
static void Main(string[] args)
{
test();
}
public void test()
{
MethodInfo mi = this.GetType().GetMethod("test2");
mi.Invoke(this, null);
}
public void test2()
{
Console.WriteLine("Test2");
}
}
I get a compiler error in test();:
An object reference is required for the non-static field.
I don't quite understand these modifiers yet so what am I doing wrong?
What I really want to do is have the test() code inside Main() but it gives me an error when I do that.
If you still want to have test() as an instance method:
class Program
{
static void Main(string[] args)
{
Program p = new Program();
p.test();
}
void Test()
{
// I'm NOT static
// I belong to an instance of the 'Program' class
// You must have an instance to call me
}
}
or rather make it static:
class Program
{
static void Main(string[] args)
{
Test();
}
static void Test()
{
// I'm static
// You can call me from another static method
}
}
To get the info of a static method:
typeof(Program).GetMethod("Test", BindingFlags.Static);
Just put all logic to another class
class Class1
{
public void test()
{
MethodInfo mi = this.GetType().GetMethod("test2");
mi.Invoke(this, null);
}
public void test2()
{
Console.Out.WriteLine("Test2");
}
}
and
static void Main(string[] args)
{
var class1 = new Class1();
class1.test();
}
The method must be static in order to call it.
Related
How can be call the method from another class inherited
let's see my code please:
class Program : classA
{
static void Main(string[] args)
{
// how i can call method ToDo without create an instance like below
//classA c = new classA();
//c.ToDo();
Console.ReadLine();
}
}
class Program2 : classB
{
static void Main(string[] args)
{
// how i can call method ToDo
//ToDo()
Console.ReadLine();
}
}
public abstract class classB
{
public void ToDo()
{
Console.WriteLine("classB");
}
}
public class classA
{
public void ToDo()
{
Console.WriteLine("classA");
}
}
how i can call the method in Either way, please help me.
There are a couple ways to do what you want to do (they're kind of similar or even the same).
One way is to create a class with a static method:
public class classA
{
public static void ToDo()
{
Console.WriteLine("classA");
}
}
then call it like:
classA.ToDo();
Another way is to add another static method to the class that contains Main:
class Program2 : classB
{
static void Main(string[] args)
{
ToDo()
Console.ReadLine();
}
static void Todo()
{
// do stuff here
}
}
If u want to call ToDo() function into [class Program : classA] and [class Program : classB]
Without creating Instance.
U have to Define ToDo() function as static, then u can call this method with class name in anywhere.
public static void ToDo(){}
What is the problem in this code?
namespace ConsoleApplication1
{
public delegate void del();
class Program
{
static void Main(string[] args)
{
del d = new del(add);
d += sub;
}
public static void add()
{
Console.WriteLine("add");
}
public static void sub()
{
Console.WriteLine("Sub");
}
}
}
You need to invoke your delegate:
class Program
{
static void Main(string[] args)
{
del d = new del(add);
d += sub;
d.Invoke();
}
public static void add()
{
Console.WriteLine("add");
}
public static void sub()
{
Console.WriteLine("Sub");
}
}
}
If i implement a default async/await method like:
class Program
{
static void Main(string[] args)
{
new Program().TestMethod();
}
private async void TestMethod()
{
await Task.Delay(10);
}
}
The generated IL-Code and the async state machine contains a field "this" with a reference to the instance which invoked the method. If the code is adjusted to a static one, there is of course no "this" value.
Not to do this via reflection, more from perspective of the CLR or the debugger.
Does anyone know how i can determine within the "static TestMethod" from which method i was called - on the IL level!
class Program
{
static void Main(string[] args)
{
TestMethod();
}
private static async void TestMethod()
{
await Task.Delay(10);
}
}
how i can determine within the "static TestMethod" from which method i was called
You can use CallerMemberName attribute
static void Main(string[] args)
{
new Program().TestMethod();
Console.ReadLine();
}
private async void TestMethod([CallerMemberName]string caller = "")
{
Console.WriteLine(caller);
}
PS: You can also use CallerFilePath or CallerLineNumber
using System;
using System.Diagnostics;
namespace Cli
{
class Program
{
static void Main(string[] args)
{
new Program().TestMethod();
}
private void TestMethod()
{
var sf = new StackFrame(1); //get caller stackframe
var mi = sf.GetMethod(); //get method info of caller
Console.WriteLine("{0}::{1}", mi.DeclaringType, mi.Name);
// Cli.Program::Main
}
}
}
I want to call a public Methode(Send) in a process from my c# project!
This is the process with the Methode that i want to call :
namespace Test123
{
class Program
{
static void Main(string[] args)
{
while(true)
{
}
}
public void Send()
{
Console.WriteLine("Test");
}
}
}
I know how to get the process but not how to invoke the methode!
I already searched on other websites and i din´t found anything that helps me.
Create a instance of the program in the static and call the method.
class Program
{
static void Main(string[] args)
{
var p = new Program();
while(true)
{
p.Send();
}
}
public void Send()
{
Console.WriteLine("Test");
}
}
If your in the same Program class, you can just call the method. The other approach listed where you declare a new Program, would be needed if you were in a different class.
static void Main(string[] args)
{
while(true)
{
Send();
}
}
Hello friends I face this question in one Interview in statics(Myclass). I have two clases one is M1 and M2.
How can I call m2 in m1 and m1 in m2? and also How to create an Instance of an static?
static void Main(string[] args)
{
//in this Portion How can I call all member if MyClass
}
public static class Myclass
{
public static class M1
{
//Here How can I call m2
}
public class m2
{
//Here How can I call m1
}
}
For static class M1, you need to call using class name.
For non static class M2, you need to create instance.
you can call methods/properties, and not classes.
public static class Myclass
{
public static void Main(String[] args)
{
// call something on m2
var m2 = new Myclass.m2();
m2.A2(); // call m2.A2 method
// call something on m1
Myclass.m1.A1();
}
public static class M1
{
//Here How can I call m2
public static void A1()
{
var m2 = new Myclass.m2(); // create m2instance
m2.A2(); // call m2
}
}
public class m2
{
//Here How can I call m1
public void A2()
{
Myclass.M1.A1(); // called M1.A1
}
}
}
You can not call a class, and as it is static you can not Generate new class of that type but you can call methods and functions of it easily like this:
public static class Myclass
{
public static class M1
{
public static class Method2(){
}
new m2().AMethod();
}
public class m2
{
//Here How can I call m1
public static void AMethod(){
//method
}
}
}
And for main:
static void Main(string[] args)
{
new MyClass.m2().AMethod();
MyClass.M1.Method2();
}