Вот код frmNeuPatient.Designer.cs:

namespace HospitalSW
{
  partial class frmNeuPatient
  {
    /// <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.components = new System.ComponentModel.Container();
      this.lbGeschlecht = new System.Windows.Forms.Label();
      this.cboGeschlecht = new System.Windows.Forms.ComboBox();
      this.lbVorname = new System.Windows.Forms.Label();
      this.txtVorname = new System.Windows.Forms.TextBox();
      this.lbNachname = new System.Windows.Forms.Label();
      this.txtNachname = new System.Windows.Forms.TextBox();
      this.lbGeburtsdatum = new System.Windows.Forms.Label();
      this.mstxtBirthday = new System.Windows.Forms.MaskedTextBox();
      this.btnSelectBirthday = new System.Windows.Forms.Button();
      this.lbWohnaddresseDesPatientes = new System.Windows.Forms.Label();
      this.lbPersonalDatenDesPatientes = new System.Windows.Forms.Label();
      this.lbStrasse = new System.Windows.Forms.Label();
      this.textBox1 = new System.Windows.Forms.TextBox();
      this.textBox2 = new System.Windows.Forms.TextBox();
      this.lbHaus = new System.Windows.Forms.Label();
      this.btnSpeichern = new System.Windows.Forms.Button();
      this.btnAbbrechen = new System.Windows.Forms.Button();
      this.lbPLZ = new System.Windows.Forms.Label();
      this.txtPLZ = new System.Windows.Forms.TextBox();
      this.lbStadt = new System.Windows.Forms.Label();
      this.txtStadt = new System.Windows.Forms.TextBox();
      this.popupStadt = new System.Windows.Forms.ContextMenuStrip(this.components);
      this.cToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
      this.btnSuchePLZ = new System.Windows.Forms.Button();
      this.btnSucheStadt = new System.Windows.Forms.Button();
      this.popupStadt.SuspendLayout();
      this.SuspendLayout();
      // 
      // lbGeschlecht
      // 
      this.lbGeschlecht.AutoSize = true;
      this.lbGeschlecht.Location = new System.Drawing.Point(18, 36);
      this.lbGeschlecht.Name = "lbGeschlecht";
      this.lbGeschlecht.Size = new System.Drawing.Size(30, 13);
      this.lbGeschlecht.TabIndex = 1;
      this.lbGeschlecht.Text = "Пол:";
      // 
      // cboGeschlecht
      // 
      this.cboGeschlecht.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
      this.cboGeschlecht.FormattingEnabled = true;
      this.cboGeschlecht.Location = new System.Drawing.Point(116, 33);
      this.cboGeschlecht.Name = "cboGeschlecht";
      this.cboGeschlecht.Size = new System.Drawing.Size(121, 21);
      this.cboGeschlecht.TabIndex = 2;
      // 
      // lbVorname
      // 
      this.lbVorname.AutoSize = true;
      this.lbVorname.Location = new System.Drawing.Point(18, 70);
      this.lbVorname.Name = "lbVorname";
      this.lbVorname.Size = new System.Drawing.Size(32, 13);
      this.lbVorname.TabIndex = 3;
      this.lbVorname.Text = "Имя:";
      // 
      // txtVorname
      // 
      this.txtVorname.Location = new System.Drawing.Point(116, 67);
      this.txtVorname.Name = "txtVorname";
      this.txtVorname.Size = new System.Drawing.Size(297, 20);
      this.txtVorname.TabIndex = 4;
      // 
      // lbNachname
      // 
      this.lbNachname.AutoSize = true;
      this.lbNachname.Location = new System.Drawing.Point(18, 105);
      this.lbNachname.Name = "lbNachname";
      this.lbNachname.Size = new System.Drawing.Size(59, 13);
      this.lbNachname.TabIndex = 5;
      this.lbNachname.Text = "Фамилия:";
      // 
      // txtNachname
      // 
      this.txtNachname.Location = new System.Drawing.Point(116, 102);
      this.txtNachname.Name = "txtNachname";
      this.txtNachname.Size = new System.Drawing.Size(297, 20);
      this.txtNachname.TabIndex = 6;
      // 
      // lbGeburtsdatum
      // 
      this.lbGeburtsdatum.AutoSize = true;
      this.lbGeburtsdatum.Location = new System.Drawing.Point(18, 139);
      this.lbGeburtsdatum.Name = "lbGeburtsdatum";
      this.lbGeburtsdatum.Size = new System.Drawing.Size(89, 13);
      this.lbGeburtsdatum.TabIndex = 7;
      this.lbGeburtsdatum.Text = "Дата рождения:";
      // 
      // mstxtBirthday
      // 
      this.mstxtBirthday.Location = new System.Drawing.Point(116, 136);
      this.mstxtBirthday.Mask = "00/00/0000";
      this.mstxtBirthday.Name = "mstxtBirthday";
      this.mstxtBirthday.Size = new System.Drawing.Size(100, 20);
      this.mstxtBirthday.TabIndex = 8;
      this.mstxtBirthday.ValidatingType = typeof(System.DateTime);
      // 
      // btnSelectBirthday
      // 
      this.btnSelectBirthday.Location = new System.Drawing.Point(222, 132);
      this.btnSelectBirthday.Name = "btnSelectBirthday";
      this.btnSelectBirthday.Size = new System.Drawing.Size(28, 26);
      this.btnSelectBirthday.TabIndex = 9;
      this.btnSelectBirthday.Text = "...";
      this.btnSelectBirthday.UseVisualStyleBackColor = true;
      this.btnSelectBirthday.Click += new System.EventHandler(this.btnSelectBirthday_Click);
      // 
      // lbWohnaddresseDesPatientes
      // 
      this.lbWohnaddresseDesPatientes.AutoSize = true;
      this.lbWohnaddresseDesPatientes.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
      this.lbWohnaddresseDesPatientes.Location = new System.Drawing.Point(13, 191);
      this.lbWohnaddresseDesPatientes.Name = "lbWohnaddresseDesPatientes";
      this.lbWohnaddresseDesPatientes.Size = new System.Drawing.Size(182, 13);
      this.lbWohnaddresseDesPatientes.TabIndex = 10;
      this.lbWohnaddresseDesPatientes.Text = "Адрес проживания пациента:";
      // 
      // lbPersonalDatenDesPatientes
      // 
      this.lbPersonalDatenDesPatientes.AutoSize = true;
      this.lbPersonalDatenDesPatientes.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
      this.lbPersonalDatenDesPatientes.Location = new System.Drawing.Point(13, 9);
      this.lbPersonalDatenDesPatientes.Name = "lbPersonalDatenDesPatientes";
      this.lbPersonalDatenDesPatientes.Size = new System.Drawing.Size(206, 13);
      this.lbPersonalDatenDesPatientes.TabIndex = 0;
      this.lbPersonalDatenDesPatientes.Text = "Персональные данные пациента:";
      // 
      // lbStrasse
      // 
      this.lbStrasse.AutoSize = true;
      this.lbStrasse.Location = new System.Drawing.Point(21, 225);
      this.lbStrasse.Name = "lbStrasse";
      this.lbStrasse.Size = new System.Drawing.Size(42, 13);
      this.lbStrasse.TabIndex = 11;
      this.lbStrasse.Text = "Улица:";
      // 
      // textBox1
      // 
      this.textBox1.Location = new System.Drawing.Point(116, 222);
      this.textBox1.Name = "textBox1";
      this.textBox1.Size = new System.Drawing.Size(171, 20);
      this.textBox1.TabIndex = 12;
      // 
      // textBox2
      // 
      this.textBox2.Location = new System.Drawing.Point(332, 222);
      this.textBox2.Name = "textBox2";
      this.textBox2.Size = new System.Drawing.Size(81, 20);
      this.textBox2.TabIndex = 14;
      // 
      // lbHaus
      // 
      this.lbHaus.AutoSize = true;
      this.lbHaus.Location = new System.Drawing.Point(293, 225);
      this.lbHaus.Name = "lbHaus";
      this.lbHaus.Size = new System.Drawing.Size(33, 13);
      this.lbHaus.TabIndex = 13;
      this.lbHaus.Text = "Дом:";
      // 
      // btnSpeichern
      // 
      this.btnSpeichern.Location = new System.Drawing.Point(24, 387);
      this.btnSpeichern.Name = "btnSpeichern";
      this.btnSpeichern.Size = new System.Drawing.Size(75, 23);
      this.btnSpeichern.TabIndex = 19;
      this.btnSpeichern.Text = "&Сохранить";
      this.btnSpeichern.UseVisualStyleBackColor = true;
      this.btnSpeichern.Click += new System.EventHandler(this.btnSpeichern_Click);
      // 
      // btnAbbrechen
      // 
      this.btnAbbrechen.Location = new System.Drawing.Point(113, 387);
      this.btnAbbrechen.Name = "btnAbbrechen";
      this.btnAbbrechen.Size = new System.Drawing.Size(75, 23);
      this.btnAbbrechen.TabIndex = 20;
      this.btnAbbrechen.Text = "&Отмена";
      this.btnAbbrechen.UseVisualStyleBackColor = true;
      this.btnAbbrechen.Click += new System.EventHandler(this.btnAbbrechen_Click);
      // 
      // lbPLZ
      // 
      this.lbPLZ.AutoSize = true;
      this.lbPLZ.Location = new System.Drawing.Point(21, 262);
      this.lbPLZ.Name = "lbPLZ";
      this.lbPLZ.Size = new System.Drawing.Size(81, 13);
      this.lbPLZ.TabIndex = 15;
      this.lbPLZ.Text = "Почтовый код:";
      // 
      // txtPLZ
      // 
      this.txtPLZ.AutoCompleteCustomSource.AddRange(new string[] {
      "aa"});
      this.txtPLZ.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.SuggestAppend;
      this.txtPLZ.Location = new System.Drawing.Point(116, 259);
      this.txtPLZ.Name = "txtPLZ";
      this.txtPLZ.Size = new System.Drawing.Size(87, 20);
      this.txtPLZ.TabIndex = 16;
      this.txtPLZ.TextChanged += new System.EventHandler(this.txtPLZ_TextChanged);
      // 
      // lbStadt
      // 
      this.lbStadt.AutoSize = true;
      this.lbStadt.Location = new System.Drawing.Point(238, 262);
      this.lbStadt.Name = "lbStadt";
      this.lbStadt.Size = new System.Drawing.Size(40, 13);
      this.lbStadt.TabIndex = 17;
      this.lbStadt.Text = "Город:";
      // 
      // txtStadt
      // 
      this.txtStadt.Location = new System.Drawing.Point(281, 259);
      this.txtStadt.Name = "txtStadt";
      this.txtStadt.Size = new System.Drawing.Size(110, 20);
      this.txtStadt.TabIndex = 18;
      this.txtStadt.TextChanged += new System.EventHandler(this.txtStadt_TextChanged);
      // 
      // popupStadt
      // 
      this.popupStadt.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
      this.cToolStripMenuItem});
      this.popupStadt.Name = "popupStadt";
      this.popupStadt.RenderMode = System.Windows.Forms.ToolStripRenderMode.System;
      this.popupStadt.Size = new System.Drawing.Size(102, 28);
      // 
      // cToolStripMenuItem
      // 
      this.cToolStripMenuItem.Name = "cToolStripMenuItem";
      this.cToolStripMenuItem.Size = new System.Drawing.Size(101, 24);
      this.cToolStripMenuItem.Text = "c";
      // 
      // btnSuchePLZ
      // 
      this.btnSuchePLZ.Location = new System.Drawing.Point(209, 259);
      this.btnSuchePLZ.Name = "btnSuchePLZ";
      this.btnSuchePLZ.Size = new System.Drawing.Size(28, 23);
      this.btnSuchePLZ.TabIndex = 21;
      this.btnSuchePLZ.Text = "...";
      this.btnSuchePLZ.UseVisualStyleBackColor = true;
      this.btnSuchePLZ.Click += new System.EventHandler(this.btnSucheStadt_Click);
      // 
      // btnSucheStadt
      // 
      this.btnSucheStadt.Location = new System.Drawing.Point(397, 259);
      this.btnSucheStadt.Name = "btnSucheStadt";
      this.btnSucheStadt.Size = new System.Drawing.Size(28, 23);
      this.btnSucheStadt.TabIndex = 22;
      this.btnSucheStadt.Text = "...";
      this.btnSucheStadt.UseVisualStyleBackColor = true;
      this.btnSucheStadt.Click += new System.EventHandler(this.btnSucheStadt_Click);
      // 
      // frmNeuPatient
      // 
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
      this.ClientSize = new System.Drawing.Size(438, 422);
      this.Controls.Add(this.btnSucheStadt);
      this.Controls.Add(this.btnSuchePLZ);
      this.Controls.Add(this.btnAbbrechen);
      this.Controls.Add(this.txtStadt);
      this.Controls.Add(this.lbStadt);
      this.Controls.Add(this.txtPLZ);
      this.Controls.Add(this.btnSpeichern);
      this.Controls.Add(this.lbPersonalDatenDesPatientes);
      this.Controls.Add(this.lbPLZ);
      this.Controls.Add(this.lbHaus);
      this.Controls.Add(this.textBox2);
      this.Controls.Add(this.textBox1);
      this.Controls.Add(this.lbStrasse);
      this.Controls.Add(this.lbGeschlecht);
      this.Controls.Add(this.btnSelectBirthday);
      this.Controls.Add(this.lbWohnaddresseDesPatientes);
      this.Controls.Add(this.mstxtBirthday);
      this.Controls.Add(this.lbGeburtsdatum);
      this.Controls.Add(this.txtNachname);
      this.Controls.Add(this.lbNachname);
      this.Controls.Add(this.txtVorname);
      this.Controls.Add(this.lbVorname);
      this.Controls.Add(this.cboGeschlecht);
      this.Name = "frmNeuPatient";
      this.Text = "Новый пациент";
      this.Load += new System.EventHandler(this.frmNeuPatient_Load);
      this.popupStadt.ResumeLayout(false);
      this.ResumeLayout(false);
      this.PerformLayout();
    }
    #endregion
    private System.Windows.Forms.Label lbGeschlecht;
    private System.Windows.Forms.ComboBox cboGeschlecht;
    private System.Windows.Forms.Label lbVorname;
    private System.Windows.Forms.TextBox txtVorname;
    private System.Windows.Forms.Label lbNachname;
    private System.Windows.Forms.TextBox txtNachname;
    private System.Windows.Forms.Label lbGeburtsdatum;
    private System.Windows.Forms.MaskedTextBox mstxtBirthday;
    private System.Windows.Forms.Button btnSelectBirthday;
    private System.Windows.Forms.Label lbWohnaddresseDesPatientes;
    private System.Windows.Forms.Label lbPersonalDatenDesPatientes;
    private System.Windows.Forms.Label lbStrasse;
    private System.Windows.Forms.TextBox textBox1;
    private System.Windows.Forms.TextBox textBox2;
    private System.Windows.Forms.Label lbHaus;
    private System.Windows.Forms.Button btnSpeichern;
    private System.Windows.Forms.Button btnAbbrechen;
    private System.Windows.Forms.Label lbPLZ;
    private System.Windows.Forms.TextBox txtPLZ;
    private System.Windows.Forms.Label lbStadt;
    private System.Windows.Forms.TextBox txtStadt;
    private System.Windows.Forms.ContextMenuStrip popupStadt;
    private System.Windows.Forms.ToolStripMenuItem cToolStripMenuItem;
    private System.Windows.Forms.Button btnSuchePLZ;
    private System.Windows.Forms.Button btnSucheStadt;
  }
}

Вот код frmNeuPatient.cs, вот так надо комментировать каждую строчку но на немецком языке, иначе уволят с работы:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Resources;
using System.Reflection;

namespace HospitalSW
{
  public partial class frmNeuPatient : Form
  {
    private const String cAnredeSQL = "SELECT AnredeID, Bezeichnen FROM tblAnrede";
    private const String cConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" + 
    @"Data Source=C:\hospital2024\hospitaldb.mdb";

    private ResourceManager rm = null;
    /// <summary>
    /// Конструктор формы
    /// </summary>
    public frmNeuPatient()
    {
      InitializeComponent();
      //rm = new ResourceManager("frmNeuPatient.Resource1", _currAssembly);
      //MessageBox.Show(rm.GetString("C_ERROR_DB"));
    }

    /// <summary>
    /// Выдаёт диалоговое окно с сообщением ошибки
    /// </summary>
    /// <param name="strError">Текст с ошибкой</param>
    /// <param name="strTitle">Заголовок окна</param>
    /// <returns>Ничего не возвращает</returns>
    private void ShowErrorMessageBox(String strError, String strTitle)
    {
      /* Отображает диалоговое сообщение с ошибкой */
      MessageBox.Show(strError, strTitle, MessageBoxButtons.OK, MessageBoxIcon.Error);
    }

    /// <summary>
    /// Выдаёт диалоговое окно с кодом ошибки и с сообщением ошибки
    /// </summary>
    /// <param name="intErrorid">Код ошибки</param>
    /// <param name="strError">Текст с ошибкой</param>
    /// <param name="strTitle">Заголовок окна</param>
    /// <returns>Ничего не возвращает</returns>
    private void ShowErrorMessageBox(int intErrorid, String strError, String strTitle)
    {
        this.ShowErrorMessageBox("Код ошибки:" + intErrorid.ToString() + " " + strError, strTitle);
    }

    /// <summary>
    /// Срабаатывает при загрузки формы
    /// </summary>
    /// <param name="sender">...</param>
    /// <param name="e">...</param>
    /// <returns>Ничего не возвращает</returns>
    /// <exception>Если не сможет подключиться к СУБД или открыть базу данных, то произойдёт ошибка и отоброзится
    /// диалоговое окно с ошибкой.
    /// </exception>
    private void frmNeuPatient_Load(object sender, EventArgs e)
    {
      /* Для combobox/dropdown Пол */
      try {
        /* Подключается к СУБД Microsoft Access и открывает базу данных hospitaldb.mdb */
        OleDbConnection conAnrede = new OleDbConnection(cConnectionString);
        /* Открывает соединение */
        conAnrede.Open();
        /* Выполняет SQL-запрос */
        OleDbDataAdapter daAnrede = new OleDbDataAdapter(cAnredeSQL, conAnrede);
        DataTable dtAnrede = new DataTable();
        daAnrede.Fill(dtAnrede);
        /* Для значения в ComboBox */
        this.cboGeschlecht.ValueMember = "AnredeID";
        /* То что отображается в ComboBox */
        this.cboGeschlecht.DisplayMember = "Bezeichnen";
        /* Связывается с СУБД, и добавляет данные в ComboBox */
        this.cboGeschlecht.DataSource = dtAnrede;                
      }
      catch(Exception ex) {
        /* Отображает диалоговое сообщение с ошибкой */                
        this.ShowErrorMessageBox("Ощибка невозможно открыть базу данных!", "Ошибка");
      }
   }
 
   private void btnSelectBirthday_Click(object sender, EventArgs e)
   {
     frmCalendar frmCalend = new frmCalendar(this.mstxtBirthday);
     frmCalend.Show();
   }

   private void txtPLZ_TextChanged(object sender, EventArgs e)
   {
     this.popupStadt.Show(new Point(this.txtPLZ.Left, 200));
   }

   private void txtStadt_TextChanged(object sender, EventArgs e)
   { }
  
   private void btnSpeichern_Click(object sender, EventArgs e)
   {
     try
       { }
     catch (Exception ex)
       { }
     this.Close();
   }

   private void btnAbbrechen_Click(object sender, EventArgs e)
   {
     this.Close();
   }

   private void btnSucheStadt_Click(object sender, EventArgs e)
   {
     frmStadtSuchen frmSS = new frmStadtSuchen(this.txtStadt, this.txtPLZ);
     frmSS.Show();
   }
 }
}