cicatrix

public class XmlEntry
{
    public DateTime Date { get; set; }
    public float[] Values { get; set; }
} // class XmlEntry

public IEnumerable<XmlEntry> ReadFile(string filename)
{
    XmlDocument doc = new XmlDocument();
    doc.Load(filename);
    return doc.SelectNodes("dataset/data/datum") // Здесь возможно подредактировать путь надо, у вас XML обрезан
        .OfType<XmlElement>()
        .Select(e => new XmlEntry
        {
            Date = DateTime.Parse(
                e.ChildNodes.OfType<XmlElement>()
                .Where(cn =>
                    cn.Attributes["type"].Value.Equals("date")).FirstOrDefault().InnerText),
            Values =
                e.ChildNodes.OfType<XmlElement>()
                .Where(cn =>
                    cn.Attributes["type"].Value.Equals("float"))
                    .Select(node => float.Parse(node.InnerText, System.Globalization.CultureInfo.InvariantCulture))
                    .ToArray()
        }); 
} // ReadFile

namespace FormLoginDemo
{
    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.txtLogin = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.txtPassword = new System.Windows.Forms.TextBox();
            this.button1 = new System.Windows.Forms.Button();
            this.label3 = new System.Windows.Forms.Label();
            this.lnkReg = new System.Windows.Forms.LinkLabel();
            this.SuspendLayout();
            // 
            // txtLogin
            // 
            this.txtLogin.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
            this.txtLogin.Font = new System.Drawing.Font("Arial", 18F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.txtLogin.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(64)))), ((int)(((byte)(64)))), ((int)(((byte)(64)))));
            this.txtLogin.Location = new System.Drawing.Point(71, 97);
            this.txtLogin.Margin = new System.Windows.Forms.Padding(6);
            this.txtLogin.Name = "txtLogin";
            this.txtLogin.Size = new System.Drawing.Size(298, 35);
            this.txtLogin.TabIndex = 0;
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.label1.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(64)))), ((int)(((byte)(64)))), ((int)(((byte)(64)))));
            this.label1.Location = new System.Drawing.Point(67, 71);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(59, 20);
            this.label1.TabIndex = 1;
            this.label1.Text = "Логин:";
            // 
            // label2
            // 
            this.label2.AutoSize = true;
            this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.label2.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(64)))), ((int)(((byte)(64)))), ((int)(((byte)(64)))));
            this.label2.Location = new System.Drawing.Point(67, 143);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(71, 20);
            this.label2.TabIndex = 3;
            this.label2.Text = "Пароль:";
            // 
            // txtPassword
            // 
            this.txtPassword.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
            this.txtPassword.Font = new System.Drawing.Font("Arial", 18F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.txtPassword.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(64)))), ((int)(((byte)(64)))), ((int)(((byte)(64)))));
            this.txtPassword.Location = new System.Drawing.Point(71, 169);
            this.txtPassword.Margin = new System.Windows.Forms.Padding(6);
            this.txtPassword.Name = "txtPassword";
            this.txtPassword.PasswordChar = '•';
            this.txtPassword.Size = new System.Drawing.Size(298, 35);
            this.txtPassword.TabIndex = 2;
            // 
            // button1
            // 
            this.button1.BackColor = System.Drawing.Color.Black;
            this.button1.FlatAppearance.BorderColor = System.Drawing.Color.DimGray;
            this.button1.FlatAppearance.MouseDownBackColor = System.Drawing.Color.Gray;
            this.button1.FlatAppearance.MouseOverBackColor = System.Drawing.Color.White;
            this.button1.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
            this.button1.Font = new System.Drawing.Font("Arial", 11.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.button1.ForeColor = System.Drawing.Color.White;
            this.button1.Location = new System.Drawing.Point(71, 233);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(130, 45);
            this.button1.TabIndex = 4;
            this.button1.Text = "Войти";
            this.button1.UseVisualStyleBackColor = false;
            // 
            // label3
            // 
            this.label3.AutoSize = true;
            this.label3.Font = new System.Drawing.Font("Arial", 18F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.label3.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(64)))), ((int)(((byte)(64)))), ((int)(((byte)(64)))));
            this.label3.Location = new System.Drawing.Point(29, 25);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(198, 27);
            this.label3.TabIndex = 5;
            this.label3.Text = "Авторизация ^_^";
            // 
            // lnkReg
            // 
            this.lnkReg.ActiveLinkColor = System.Drawing.Color.CornflowerBlue;
            this.lnkReg.AutoSize = true;
            this.lnkReg.Font = new System.Drawing.Font("Arial", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
            this.lnkReg.ForeColor = System.Drawing.Color.CornflowerBlue;
            this.lnkReg.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline;
            this.lnkReg.LinkColor = System.Drawing.Color.CornflowerBlue;
            this.lnkReg.Location = new System.Drawing.Point(240, 246);
            this.lnkReg.Name = "lnkReg";
            this.lnkReg.Size = new System.Drawing.Size(100, 18);
            this.lnkReg.TabIndex = 6;
            this.lnkReg.TabStop = true;
            this.lnkReg.Text = "Регистрация";
            this.lnkReg.VisitedLinkColor = System.Drawing.Color.CornflowerBlue;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.BackColor = System.Drawing.Color.White;
            this.ClientSize = new System.Drawing.Size(562, 374);
            this.ControlBox = false;
            this.Controls.Add(this.lnkReg);
            this.Controls.Add(this.label3);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.txtPassword);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.txtLogin);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
            this.Name = "Form1";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.WindowState = System.Windows.Forms.FormWindowState.Minimized;
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox txtLogin;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.TextBox txtPassword;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.LinkLabel lnkReg;
    }
}

public class XmlEntry
{
    public string Name { get; set; }
    public string Mode { get; set; }
    public string Path { get; set; }
} // class XmlEntry

public IEnumerable<XmlEntry> ReadFile(string filename)
{
    XmlDocument doc = new XmlDocument();
    doc.Load(filename);
    return doc.SelectNodes("/Backup/Bases/Base")
        .OfType<XmlElement>()
        .Select(e => new XmlEntry
        {
            Name = e.Attributes["Name"].Value,
            Mode = e.Attributes["MODE"].Value,
            Path = e.Attributes["Path"].Value
        }); // Добавить валидацию, если атрибуты не обязательны
} // ReadFile

В перечислениях допустимы только целочисленные значения (byte, sbyte, short, ushort, int, uint, long и ulong), либо char.

struct STRING_ENUMERATION
{
    public const string ENUM_A = "Это строка перечисления";
    public const string ENUM_B = "Это другая строка перечисления";
}

class Program
{
    static void Main(string[] args)
    {
        string myVar = STRING_ENUMERATION.ENUM_A;
    }
}

public static void InvokeIfRequired(this ISynchronizeInvoke obj,
                                         MethodInvoker action)
{
    if (obj.InvokeRequired) {
        var args = new object[0];
        obj.Invoke(action, args);
    } else {
        action();
    }
}

SQLiteConnection connection = new SQLiteConnection();

protected void Button1_Click(object sender, EventArgs e)
{
    string[] array = { "раз", "два", "три" };
    System.IO.File.WriteAllLines("file.txt", array);
}

protected void Button2_Click(object sender, EventArgs e)
{
    string[] array = System.IO.File.ReadAllLines("file.txt");
}