Invalid Attemp To Read.

I'm getting an error and the user selected the "Program Name" right before they pressed the button that uses the DataReader.  Do you see anything wrong? Here is my code: 

OnClick1 this.txtCourseIDHidden.Text = cboChooseProgram.SelectedValue.ToString();
2 pnlAssignParticipants.Visible = true;
3
4 string strChosenCourse;
5 strChosenCourse = "select Program_Name from Programs WHERE Course_ID = @CourseID";
6
7 SqlDataReader drChosenCourse = null;
8
9 SqlConnection connChosenCourse = new SqlConnection(ConfigurationManager.ConnectionStrings["cs"].ConnectionString);
10
11 SqlCommand cmdChosenCourse = new SqlCommand(strChosenCourse, connChosenCourse);
12 cmdChosenCourse.Parameters.AddWithValue("@CourseID", this.txtCourseIDHidden.Text);
13 try
14 {
15 connChosenCourse.Open();
16 drChosenCourse = cmdChosenCourse.ExecuteReader();
17 if (drChosenCourse.HasRows)
18 {
19 this.lblChosenProgram.Text = "You have selected: " + drChosenCourse[0].ToString() + ".";
20 }
21 else
22 {
23 lblChosenProgram.Text = "Error";
24 }
25 }


 

 The error is "Invalid attempt to read when no data is present." Is it because I'm looking for a CourseID as a string but in the table its a bigint?