static/const/readonly variable...

I must be missing something simple...

I want to have a small struct... I want 3 of the 5 variables to be constant for all instances and the other two to be variable.

However, the 3 that are constant come from an xml file.. which must be read in...not an actual string in code...

so I've tried things like

struct samplestruct
{
public string constVar1 = xmlval1; //won't compile because you can't instantiate in struct

so i tried

struct samplestruct
{
public const string constVar1 = xmlval1; //won't compile because expression must be constant

so i tried

struct samplestruct
{
public static string constVar1 = xmlval1; //won't compile because because object reference is required

so i tried

struct samplestruct
{
public readonly string constVar1 = xmlval1; //won'tt compile because you can't instantiate in struct

any ideas....

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static/const/readonly variable...

Plumpton

Structs can not have instance initializers (field per 'instance'), however, they can have static initializers (field for all 'instances'):

    public struct Foo
    {
        private static readonly string Value = CalculateValue();

        public static string CalculateValue()
        {
            // Calculate value;
        }
    }

fanis
"public string constVar1 = xmlval1;" etc...

Are you trying to assign some variable to the field You must do that kind of actions in the constructor, you know...
Jean-Marie

Hi This code is a sample that may help to solve your problem

using System;

using System.Collections.Generic;

using System.Text;

using System.Configuration;

namespace staticinitializers

{

public struct fooo

{

public static readonly int x;

public static readonly int y;

static fooo()

{

try

{

x = int.Parse(ConfigurationSettings.AppSettings["First"]);

y = int.Parse(ConfigurationSettings.AppSettings["Second"]);

}

catch (Exception e)

{

Console.WriteLine(e.Message);

}

}

}

class Program

{

static void Main(string[] args)

{

Console.WriteLine (fooo.x.ToString()+ " "+ fooo.y.ToString());

Console.ReadLine();

}

}

}

Application Configuration file that i am refereing[XML file]

< xml version="1.0" encoding="utf-8" >

<configuration>

<appSettings>

<add key ="First" value ="20" />

<add key ="Second" value ="30"/>

</appSettings>

</configuration>

Regards
GAJMAN
I would use a class instead, create read-only property procedures for properties that need to be initialized, and initialize them in the class constructor.

public class SampleClass

{

    private string _var1;

    public string Property1

    {

        get { return _var1; }

        //set property procedure is not implemented, so this value

        //can be set only from this class and not from outside

    }

    private string _var2;

    public string Property2

    {

        get { return _var2; }

        set { _var2 = value; }

    }

    public SampleClass()

    {

        //here you can read from your file, for demo initializing it to "Hi"

        _var1 = "Hi ";

        //Property2 can be changed from outside if needed. Intializing it to "There"

        _var2 = "There";

    }

}

In this code, Property1 is read-only and its value cannot be changed, outside of SampleClass.
static/const/readonly variable...

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