data insert an retrival to/from database using checked list box - c#-4.0

Question

How to insert and retrieve data to/from database using checkedlistbox in c#
here is my cod eon button click event :
string CS = ConfigurationManager.ConnectionStrings["RosterFinal"].ConnectionString;
using (SqlConnection con = new SqlConnection(CS))
{
var Sep = "";
string INSERTq = "insert into T_Entity values(#Tno,#Tname,#STime,#ETime,#Skill1,#S_Day1)";
SqlCommand cmd = new SqlCommand(INSERTq, con);
cmd.Parameters.AddWithValue("#Tno", txtTNo.Text);
cmd.Parameters.AddWithValue("#Tname", txtTNa.Text);
cmd.Parameters.AddWithValue("#STime", dateTimePicker1.Text);
cmd.Parameters.AddWithValue("#ETime", dateTimePicker2.Text);
foreach (object i in checkedListBox1.CheckedItems )
{
// cmd.Parameters.Clear();
cmd.Parameters.AddWithValue("#Skill1", checkedListBox1.SelectedItem.ToString());
}
foreach (object m in cbDay.CheckedItems)
{
// cmd.Parameters.Clear();
cmd.Parameters.AddWithValue("#S_Day1", cbDay.SelectedItem.ToString());
}
con.Open();
cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}
It is not readind the scaller parameters and givein exception that scaller parameters skill1 must be unique

Answer 1

This exception is because of setting parameters "#Skill1" and "#S_Day1" multiple times for a single insert statement.
Also, in foreach loop, you are setting the same value each time, that's of no use.
I suggest you to use following code,
using (SqlConnection con = new SqlConnection(CS))
{
var Sep = "";
string INSERTq = "insert into T_Entity values(#Tno,#Tname,#STime,#ETime,#Skill1,#S_Day1)";
SqlCommand cmd = new SqlCommand(INSERTq, con);
cmd.Parameters.AddWithValue("#Tno", txtTNo.Text);
cmd.Parameters.AddWithValue("#Tname", txtTNa.Text);
cmd.Parameters.AddWithValue("#STime", dateTimePicker1.Text);
cmd.Parameters.AddWithValue("#ETime", dateTimePicker2.Text);
cmd.Parameters.AddWithValue("#Skill1", checkedListBox1.SelectedItem.ToString());
cmd.Parameters.AddWithValue("#S_Day1", cbDay.SelectedItem.ToString());
con.Open();
cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}

Answer 2

I think this may help u..
compare this code and modify as urs..
ConnectionStringSettings consettings = ConfigurationManager.ConnectionStrings["attendancemanagement"];
string connectionString = consettings.ConnectionString;
SqlConnection cn = new SqlConnection(connectionString);
cn.Open();
string query = "select employee_id,Employee_name from employee_details order by employee_name";
SqlCommand cmd = new SqlCommand(query, cn);
SqlDataAdapter sda ;
DataSet ds = new DataSet();
sda = new SqlDataAdapter(cmd);
sda.Fill(ds);
DataTable dt = ds.Tables[0];
foreach (DataRow datarow in dt.Rows)
{
checkedListBox1.Items.Add(datarow["employee_id"] + ": " + datarow["Employee_name"]);
}