class Test
{
   string mFileName;
   File mFile;

   Test Set_FileName(pFileName)
   {
      Test res = *this;
      res.mFileName = pFileName;
      return res;
   }

   void Init ()
   {
      mFile = FileOpen(mFileName);
   }
};

int main() {
    Test t = Test().Set_FileName("foo.txt").Init();
}

class Car ( int wheels, float max_speed )

class Test ( string path, file handle )

// фабрика
class maker ()

maker::new_car(int wheels, float max_speed)
{
  ret = new Car;
  ret.wheels = wheels;
  ret.max_speed = max_speed;
  return ret;
}

maker::new_test(string path)
{
  ret = new Test;
  ret.path = path;
  ret.handle = CreateFile(path);
  return ret;
}

// фабрика
class maker (

  Car new_car(int wheels, float max_speed)
  {
    ret = new Car;
    ret.wheels = wheels;
    ret.max_speed = max_speed;
    return ret;
  }

  Test new_test(string path)
  {
    ret = new Test;
    ret.path = path;
    ret.handle = CreateFile(path);
    return ret;
  }
)

lStr_ClassName = "T_Test";
lObj = CreateObject(lStr_ClassName);

Class MainForm
{
    string mFileName;
    
    void OnButton_ReadDatabase()
    {
        T_DatabaseInfo lDatabaseInfo = new T_DatabaseInfo(mFileName);
        T_DBGoodsReader lDBGoodsReader = new T_DBGoodsReader;
        I_DBAdapter lDBAdapter = null;
        
        if lDatabaseInfo.DBType = Database.DBType1 then
            lDBAdapter = new T_DBAdapter1(mFileName);
        elseif lDatabaseInfo.DBType = Database.DBType2
            lDBAdapter = new T_DBAdapter2(mFileName);
        else
            // исключение "неизвестный тип БД
        endif
        
        lDBGoodsReader.SetAdapter(lAdapter);
        lDBGoodsReader.Init();
        lDBGoodsReader.Read();
        
        // показать на форме список товаров
    }
}

class Test
{
   string mFileName;
   File mFile;

   Test Set_FileName(pFileName)
   {
      Test res = *this;
      res.mFileName = pFileName;
      return res;
   }

   void Init ()
   {
      mFile = FileOpen(mFileName);
   }
   Test Init_Corrected ()
   {
      Test res = *this;
      res.mFile = FileOpen(mFileName);
      return res;
   }
   int Read(byte* dest, int count)
   {
      return FileRead(mFile, dest, count);
   }
};

int main() {
   Test t1 = Test().Set_FileName("foo.txt").Init(); // compile error: cannot convert expression of type 'void' to type 'Test'
   Test t2 = Test();
   Test t3 = Test().Set_FileName("foo.txt");
   Test t4 = Test().Set_FileName("foo.txt").Init_Corrected(); 
   byte* buffer = new byte[1024];
   t2.Read(buffer, 1024); // oops
   t3.Read(buffer, 1024); // oops
   t4.Read(buffer, 1024); // :)
}

Z>Class MainForm
Z>{
Z>    string mFileName;
    
Z>    void OnButton_ReadDatabase()
Z>    {
Z>        T_DatabaseInfo lDatabaseInfo = new T_DatabaseInfo(mFileName);
Z>        T_DBGoodsReader lDBGoodsReader = new T_DBGoodsReader;
Z>        I_DBAdapter lDBAdapter = null;
        
Z>        if lDatabaseInfo.DBType = Database.DBType1 then
Z>            lDBAdapter = new T_DBAdapter1(mFileName);
Z>        elseif lDatabaseInfo.DBType = Database.DBType2
Z>            lDBAdapter = new T_DBAdapter2(mFileName);
Z>        else
Z>            // исключение "неизвестный тип БД
Z>        endif
        
Z>        lDBGoodsReader.SetAdapter(lAdapter);
Z>        lDBGoodsReader.Init();
Z>        lDBGoodsReader.Read();
        
Z>        // показать на форме список товаров
Z>    }
Z>}
Z>

    public partial class Form1 : Form {
        Resolve di = new Resolve1();
        public Form1() {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {
            comboBox1.SelectedIndex = 0;
        }
        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) {
            int num=comboBox1.SelectedIndex+1;
            di.GetConfig().SelectSource(num);
            update_goods();
        }
        void update_goods() {
            var reader=di.GetGoods();
            var lv = listView1;
            lv.BeginUpdate();
            lv.Items.Clear();
            Goods item;
            while(reader.Next(out item)) {
                var li = new ListViewItem();
                li.Text = item.name;
                li.SubItems.Add(String.Format("{0}", item.amount));
                li.SubItems.Add(String.Format("{0:F2}", item.price));
                lv.Items.Add(li);
            }
            lv.EndUpdate();
        }
    }

    class Goods {
        public string name = "";
        public double amount = 0;
        public double price = 0;
    };
    interface GoodsReader {
        bool Next(out Goods item);
    };
    interface Config {
        void SelectSource(int num);
    }
    interface Resolve {
        GoodsReader GetGoods();
        Config GetConfig();
    }

    class GoodsReader1 : GoodsReader {
        int index = 0;
        Goods[] list = new Goods[]{
            new Goods() { name="good1", amount=4, price=100 },
            new Goods() { name="good2", amount=2, price=150 },
            new Goods() { name="good3", amount=1, price= 75 }
        };
        public bool Next(out Goods item) {
            if (index < 0 || index >= list.Length) { item = null; return false; }
            item = list[index++];
            return true;
        }
    }
    class GoodsReader2 : GoodsReader {
        int index = 0;
        Goods[] list = new Goods[]{
            new Goods() { name="goodA", amount=40, price=120 },
            new Goods() { name="goodB", amount=12, price=130 },
            new Goods() { name="goodC", amount=11, price= 80 },
            new Goods() { name="goodE", amount= 1, price= 30 }
        };
        public bool Next(out Goods item) {
            if (index < 0 || index >= list.Length) { item = null; return false; }
            item = list[index++];
            return true;
        }
    }
    class Config1 : Config {
        Action<int> cb;
        public void SelectSource(int num) { if (cb != null) cb(num); }
        public Config1(Action<int> cb) { this.cb = cb; }
    }

    class Resolve1 : Resolve {
        int source = 1;
        public Config GetConfig() { return new Config1(num => source = num); }
        public GoodsReader GetGoods() {
            if (source == 1) return new GoodsReader1();
            if (source == 2) return new GoodsReader2();
            throw new Exception("invalid data source");
        }

    }

    partial class Form1 {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing) {
            if (disposing && (components != null)) {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent() {
            this.comboBox1 = new System.Windows.Forms.ComboBox();
            this.listView1 = new System.Windows.Forms.ListView();
            this.ColName = new System.Windows.Forms.ColumnHeader();
            this.ColAmount = new System.Windows.Forms.ColumnHeader();
            this.ColPrice = new System.Windows.Forms.ColumnHeader();
            this.SuspendLayout();
            // 
            // comboBox1
            // 
            this.comboBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
                        | System.Windows.Forms.AnchorStyles.Right)));
            this.comboBox1.FormattingEnabled = true;
            this.comboBox1.Items.AddRange(new object[] {
            "Source 1",
            "Source 2"});
            this.comboBox1.Location = new System.Drawing.Point(12, 12);
            this.comboBox1.Name = "comboBox1";
            this.comboBox1.Size = new System.Drawing.Size(260, 21);
            this.comboBox1.TabIndex = 0;
            this.comboBox1.SelectedIndexChanged += new System.EventHandler(this.comboBox1_SelectedIndexChanged);
            // 
            // listView1
            // 
            this.listView1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
                        | System.Windows.Forms.AnchorStyles.Left)
                        | System.Windows.Forms.AnchorStyles.Right)));
            this.listView1.Columns.AddRange(new System.Windows.Forms.ColumnHeader[] {
            this.ColName,
            this.ColAmount,
            this.ColPrice});
            this.listView1.Location = new System.Drawing.Point(12, 48);
            this.listView1.Name = "listView1";
            this.listView1.Size = new System.Drawing.Size(260, 202);
            this.listView1.TabIndex = 1;
            this.listView1.UseCompatibleStateImageBehavior = false;
            this.listView1.View = System.Windows.Forms.View.Details;
            // 
            // ColName
            // 
            this.ColName.Text = "Name";
            // 
            // ColAmount
            // 
            this.ColAmount.Text = "Amount";
            // 
            // ColPrice
            // 
            this.ColPrice.Text = "Price";
            this.ColPrice.TextAlign = System.Windows.Forms.HorizontalAlignment.Right;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 262);
            this.Controls.Add(this.listView1);
            this.Controls.Add(this.comboBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.ComboBox comboBox1;
        private System.Windows.Forms.ListView listView1;
        private System.Windows.Forms.ColumnHeader ColName;
        private System.Windows.Forms.ColumnHeader ColAmount;
        private System.Windows.Forms.ColumnHeader ColPrice;
    }

class Test
{
   string mFileName;
   File mFile;

   void Set_FileName (pFileName)
   {
      mFileName = pFileName;
   }

   void Init ()
   {
      mFile = FileOpen(mFileName);
   }
};

lTest = new Test;
lTest.Set_FileName("c:\test_file.txt")
lTest.Init();

public Form1 GetForm1() {
  var form=new Form1()
  form.di=this;
  // еще чего-нибудь подкручиваем
  return form;
}

   using(file=helper.OpenFile(filename)) {
     ...
   }