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Unable to Set and Get the values in C#

I am trying to use setter and getter. When i debug, the value gets set but when i try to retrieve, it gets null value.
Class1.cs
private string setMAX;
public string SETMax
{
get
{
return setMAX;
}
set
{
setMAX = value;
}
}
private string value1;
public string MaxValue
{
get
{
return value1;
}
set
{
value1= value;
}
}
Class2.cs
Class1.SETMax = Class1.value1; //This gets set
Class3.cs
//When i debug, first Class1.cs and Class2.cs completes, then it comes in Class3.cs
string max = Class1.SETMax; //I GET NULL here.
I dont know where I am wrong here.Can anyone please explain me ?

You are referencing File1 as an instance. You are probably referencing different instances. You probably want static properties.
private static string setMAX;
public static string SETMax
{
get
{
return setMAX;
}
set
{
setMAX = value;
}
}

I think you have a few things mixed up so lets start from the beginning
Class1.SETMax = Class1.value1;
// for a start you are assigning a
// private variable to a public one
// via the Class definition I'm not even sure how that compiles.
Have a look here see if this makes sense to you
// This is a Class definition
public class Class1 {
public string SETMax {get; set;}
public int MaxValue {get; set;}
}
// This is your application
public class MyApp{
// this is a private field where you will assign an instance of Class1
private Class1 class1Instance ;
public MyApp(){
//assign the instance in the constructor
class1Instance = new Class1();
}
public void Run {
// now for some fun
class1Instance.SETMax = "Hello";
Console.WriteLine(class1Instance.SETMax); // outputs "Hello"
var localInstance = new Class1();
localInstance.SETMax = class1Instance.SETMax;
Console.WriteLine(localInstance.SETMax); // outputs "Hello"
}
}

C# How to treat static class as a variable

I have a static Class and within it I have multiple public static attributes. I treat this class as my global class.
However now I need to treat this class as a variable so that I can pass it to a method of another class for processing..
I can't instantiate this class.. So in effect I can only assign the variables inside this class.
Is my understanding correct or am I missing something?
public static class Global
{
public const int RobotMax = 2;
// GUI sync context
public static MainForm mainForm;
public static SynchronizationContext UIContext;
// Database
public static Database DB = null;
public static string localDBName = "local.db";
public static Database localDB = null;
public static Database ChangeLogDB = null;
public static string changeLogDBName = "ChangeLog.db";
}
Let say I have a class like this, and I need to somehow keep a copy of this in another class maybe
public static class Global_bk
{
public const int RobotMax = 2;
// GUI sync context
public static MainForm mainForm;
public static SynchronizationContext UIContext;
// Database
public static Database DB = null;
public static string localDBName = "local.db";
public static Database localDB = null;
public static Database ChangeLogDB = null;
public static string changeLogDBName = "ChangeLog.db";
}
I need to copy the contents from Global to Global_bk.
And after that I need to compare the contents of the two classes in a method like
static class extentions
{
public static List<Variance> DetailedCompare<T>(T val1, T val2)
{
List<Variance> variances = new List<Variance>();
FieldInfo[] fi = val1.GetType().GetFields();
foreach (FieldInfo f in fi)
{
Variance v = new Variance();
v.Prop = f.Name;
v.valA = f.GetValue(val1);
v.valB = f.GetValue(val2);
if (!v.valA.Equals(v.valB))
variances.Add(v);
}
return variances;
}
}
class Variance
{
string _prop;
public string Prop
{
get { return _prop; }
set { _prop = value; }
}
object _valA;
public object valA
{
get { return _valA; }
set { _valA = value; }
}
object _valB;
public object valB
{
get { return _valB; }
set { _valB = value; }
}
}
So on my main form, how do I go about calling the compare method and passing the static Global class inside?
example: extentions.DetailedCompare(Global, Global_bk) ? Of course this would give me an error because I cant pass a type as a variable.
Please help me, this is driving me nuts...

How about the singleton pattern ? You can pass reference to shared interface (IDoable in exable below) and still have just one instance.
I.E.:
public interface IDoable {
int Value { get; set; }
void Foo();
}
public static class DoableWrapper {
private MyDoable : IDoable {
public int Value { get;set; }
public void Foo() {
}
}
private static IDoable s_Doable = new MyDoable();
public static IDoable Instance {
get { return s_Doable; }
}
}

Singleton is the way to go here. You can do it like this:
internal class SomeClass
{
private static SomeClass singleton;
private SomeClass(){} //yes: private constructor
public static SomeClass GetInstance()
{
return singleton ?? new SomeClass();
}
public int SomeProperty {get;set;}
public void SomeMethod()
{
//do something
}
}
The GetInstance Method will return you a SomeClass object that you can edit and pass into whatever you need.

You can access the members with classname.membername.
internal static class SomeClass
{
public static int SomeProperty {get;set;}
public static void SomeMethod()
{
//do something
}
}
static void main()
{
SomeClass.SomeProperty = 15;
SomeClass.SomeMethod();
}

The only way you are going to obtain a variable with the "class" information is using reflection. You can get a Type object for the class.
namespace Foo {
public class Bar
{
}
}
Type type = Type.GetType("Foo.Bar");
Otherwise, if you are really describing a class "instance" then use an object and simply instantiate one.
C# offers no other notation for class variables.

How do I get the value from a variable which has it's values assigned in another class?

I need to have a class for Variables and Methods for the sake of manageability.
The problem is I am not sure how I can access the value of the variable assigned in the method class.
Here is the variable class, it just holds variables:
namespace Classes
{
class MyVariableClass
{
public string MyVariable { get; set; }
}
}
Here is the method:
I am calling an instance of the variable class in the method class so that I can assign the variable to the values of the method.
namespace Classes
{
class MyMethods
{
MyVariableClass myVarClass = new MyVariableClass();
public void DoSomeStuff(string myString1, string myString2)
{
myVarClass.MyVariable = (!string.IsNullOrEmpty(myString2)
? myString2 : "String 2 has nothing!");
}
}
}
Finally, below is the Main Method:
When I run this code, MyVariable returns null, I am assuming I am accessing the variable before it is assigned it's values?
How do I get the variable with the values assigned in the Method class?
namespace Classes
{
class Program
{
static void Main(string[] args)
{
MyMethods myMethod = new MyMethods();
MyVariableClass myVarClass = new MyVariableClass();
string something = "something";
string nothingHere = null;
myMethod.DoSomeStuff(something, nothingHere);
//I need to call MyVariable here
//Or be able to access it's values assigned in the MyMethod Class.
Console.Write(myVarClass.MyVariable);
Console.ReadKey();
}
}
}

Problem : You are working on two different objects.
you are creating an object with an instance variable myVarClass in MyMethods class.
you are creating one more new object with an instance variable myVarClass in Main() method.
Note : You should always remeber that in object oriented programming objects are independent and maintain their own copy so modifying one object parameters/properties doesnot effect the other object parameters or properties.
Solution : instead of creating two different object create only one object with instance variable myVarClass in Main() method and pass it to the myClass method.
so you should change your myClass method DoSomeStuff() as below to accept the instance variable of `MyVariableClass``
public void DoSomeStuff(MyVariableClass myVarClass, string myString1, string myString2)
{
//do something
}
from Main() method call the above method as below:
MyVariableClass myVarClass = new MyVariableClass();
string something = "something";
string nothingHere = null;
myMethod.DoSomeStuff(myVarClass, something, nothingHere);
Complete Code:
namespace Classes
{
class MyMethods
{
public void DoSomeStuff(MyVariableClass myVarClass, string myString1, string myString2)
{
myVarClass.MyVariable = (!string.IsNullOrEmpty(myString2)
? myString2 : "String 2 has nothing!");
}
}
}
and Main Program should be :
namespace Classes
{
class Program
{
static void Main(string[] args)
{
MyMethods myMethod = new MyMethods();
MyVariableClass myVarClass = new MyVariableClass();
string something = "something";
string nothingHere = null;
myMethod.DoSomeStuff(myVarClass, something, nothingHere);
//I need to call MyVariable here
//Or be able to access it's values assigned in the MyMethod Class.
Console.Write(myVarClass.MyVariable);
Console.ReadKey();
}
}
}

The myVarClass member of MyMethods is private by default, so if you want to be able to call it from outside the class itself, then you need to make it public.
Once public, you'll able to do:
static void Main(string[] args)
{
MyMethods myMethod = new MyMethods();
MyVariableClass myVarClass = new MyVariableClass();
string something = "something";
string nothingHere = null;
myMethod.DoSomeStuff(something, nothingHere);
//I need to call MyVariable here
//Or be able to access it's values assigned in the MyMethod Class.
Console.Write(myMethod.myVarClass.MyVariable);
Console.ReadKey();
}
Also, be careful with the fact that the myVarClass defined in main is a completely different object.
Cheers

Define you class as:
namespace Classes
{
class MyMethods
{
public MyVariableClass MyVarClass {get; private set;}
public void DoSomeStuff(string myString1, string myString2)
{
if(MyVarClass == null)
{
MyVarClass = new MyVariableClass();
}
MyVarClass.MyVariable = (!string.IsNullOrEmpty(myString2)
? myString2 : "String 2 has nothing!");
}
}
}
then use as:
namespace Classes
{
class Program
{
static void Main(string[] args)
{
MyMethods myMethod = new MyMethods();
string something = "something";
string nothingHere = null;
myMethod.DoSomeStuff(something, nothingHere);
//I need to call MyVariable here
//Or be able to access it's values assigned in the MyMethod Class.
Console.Write(myMethod.MyVarClass.MyVariable);
Console.ReadKey();
}
}
}

How to access the Property value of nested class in c#

I have the following code in an assembly.
public class a
{
public class b
{
public static string obj;
public static string result
{
get
{
return obj;
}
set
{
obj = value;
}
}
}
public class c
{
string result1;
public void invoke()
{
result1 = "abc";
b.result = result1;
}
}
}
I had referenced this in another application(say for eg: client app) and trying to access the value of obj
If i invoke a value by creating an instance of the class b how i can access the value it set in the previous scope without return from the invoked method?

Since everything involved is public, you can access this value outside the assembly as follows:
public class SomeExternalClass
{
public void SomeMethod()
{
string val = a.b.result;
}
}

Delegate to an instance method cannot have null 'this'

Say I have a class declared as follows:
public class ExampleClass
{
public Action<int> Do { get; set; }
public ExampleClass()
{
}
public void FuncA(int n)
{
//irrelevant code here
}
public void FuncB(int n)
{
//other irrelevant code here
}
}
I want to be able to use this class like this
ExampleClass excl = new ExampleClass() { Do = FuncA }
or
ExampleClass excl = new ExampleClass() { Do = excl.FuncA }
or
ExampleClass excl = new ExampleClass() { Do = ExampleClass.FuncA }
I can compile the second option there, but I get a "Delegate to an instance method cannot have null 'this'." exception when I hit that code. The third one doesn't even make sense, because FuncA isn't static.
In my actual code, there will be maybe 10-15 different functions it could get tied to, and I could be adding or removing them at any time, so I don't want to have to have a large switch or it-else statement. Additionally, being able assign a value to 'Do' when instantiating the class is very convenient.
Am I just using incorrect syntax? Is there a better way to create a class and assign an action in one line? Should I just man up and manage a huge switch statement?

You have to create the instance of the class and later set the property to the instance member. Something like:
ExampleClass excl = new ExampleClass();
excl.Do = excl.FuncA;
For your line:
ExampleClass excl = new ExampleClass() { Do = FuncA }
FuncA is not visible without an instance of the class.
For:
ExampleClass excl = new ExampleClass() { Do = excl.FuncA }
Instance has not yet been created that is why you are getting the exception for null reference.
For:
ExampleClass excl = new ExampleClass() { Do = ExampleClass.FuncA }
FuncA is not a static method, you can't access it with the class name.

In object initializer syntax you cannot access the variable being initialized before it is definitely assigned:
ExampleClass excl = new ExampleClass()
{
Do = excl.FuncA //excl is unavailable here
}
Read Object and Collection Initializers (C# Programming Guide) for more info.
You could do the following, for example:
public class ExampleClass
{
public Action<int> Do { get; set; }
public ExampleClass(bool useA)
{
if (useA)
Do = FuncA;
else
Do = FuncB;
}
public void FuncA(int n)
{
//irrelevant code here
}
public void FuncB(int n)
{
//other irrelevant code here
}
}
and use it:
ExampleClass exclA = new ExampleClass(true);
ExampleClass exclB = new ExampleClass(false);
Another idea is if these functions may be declared as static (i.e. they don't need any instance members of the ExampleClass), then this would work:
public class ExampleClass
{
public Action<int> Do { get; set; }
public ExampleClass() { }
public static void FuncA(int n) { /*...*/}
public static void FuncB(int n) { /*...*/}
}
and use it the way you want:
ExampleClass excl = new ExampleClass() { Do = ExampleClass.FuncA };

If you have extension methods make sure that those values are not null before invoking the extension methods or handle nulls inside the extension methods.
For example
public static ExtensionClass
{
public static bool RunExtensionMethod(this object myObject)
{
var someExecutionOnMyObject = myObject.IsValid();
//the above line would invoke the exception when myObject is null
return someExecutionOnMyObject ;
}
}
public void CallingMethod()
{
var myObject = getMyObject();
if(myObject.RunExtensionMethod()) //This would cause "delete to an instance method cannot have null" if myObject is null
{
}
}
To handle this scenario handle nulls and assert nulls if you own the extension class.
public static ExtensionClass
{
public static bool RunExtensionMethod(this object myObject)
{
if(myObject == null) throw new ArgumentNullException(nameof(myObject));
var someExecutionOnMyObject = myObject.IsValid();
return someExecutionOnMyObject ;
}
}
public void CallingMethod()
{
var myObject = getMyObject();
if(myObject != null && myObject.RunExtensionMethod())
{
}
}