Question

I am a vb.net programmer switching to C#.

I have the following code for a console application (targeting NET20)

using System;
using System.IO;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;


namespace eScoreSwapper
{
    class Program
    {
        private string _dbName = ConfigurationManager.AppSettings["dbName"];

        static void Main(string[] args) {}

        static void InitVars()
        {
            if (string.IsNullOrEmpty(_dbName)) _dbName = "";
        }
    }
}

This is giving a compile error in the if clause of InitVars for the _dbName variable:

Error   1   An object reference is required for the non-static field, method, or property 'eScoreSwapper.Program._dbName'   C:\Users\SethS\Documents\eScore\Versions\Trunk\dotNet\eScoreSwapper\eScoreSwapper\Program.cs    26  38  eScoreSwapper

Is it because it is true. C# does not allow you to reference private class fields unless they are declared static? I am sure I am doing something wrong.

While I am at it can I ask another C# question. Why is the if statement valid? Why are braces not required? Is it valid syntax as long as if condition is followed by a single expression (as in t-sql IF ).

Thanks for your help.

Seth

Answer 1

No, but private fields used by static method do. What I think you really want to do is remove the static from the declaration of InitVars().

I’m gonna assume that you previously tried:

static void Main(string[] args) 
{
   InitVars();
} 

and that failed, so you added the static to InitVars(). Wrong answer. Basically, you should pretend Main() is not part of the class.

static void Main(string[] args) 
{
   Program prog = new Program();
   prog.InitVars();
} 

As far the If() statement

if (string.IsNullOrEmpty(_dbName)) _dbName = "";

is just a short version of:

if (string.IsNullOrEmpty(_dbName)) 
     _dbName = "";

Now, in C-ish language, officially, an if() that is true, will execute the (one) next statement. But, you can make several statement into one statement, by wrapping them in curly-braces. But, if you really only have one statement, they aren’t needed.