title: How to display a value from a ComboBox in a TextBox?
body: <p>I have a table in a SQL Server database called "course", which contain 60 courses.</p>
  
  <p>The table contain two columns: <code>COURSE_ID (PK), COURSE_NAME</code></p>
  
  <p>I get all courses from the database using a stored procedure:</p>
  
  <pre><code>create PROC [dbo].[GET_ALL_COURSES]
  AS
  SELECT * FROM COURSE
  </code></pre>
  
  <p>And populate a <code>ComboBox</code> like this:</p>
  
  <pre><code>public FORM_CRS()
  {
      InitializeComponent();
  
      CMB_COURSE.DataSource = CRS.GET_ALL_COURSES();
      CMB_COURSE.DisplayMember = "COURSE_NAME";
      CMB_COURSE.ValueMember = "COURSE_ID";
  }
  </code></pre>
  
  <p>When I click on a course in the <code>ComboBox</code> I want to show the <code>COURSE_ID</code> of that course in a <code>TextBox</code>, but I don't know how.</p>