Help with a data fill with textbox

Question

Hello, I want to add multiple pieces of data to the database with only one textbox.
I have a form with SQL Connection, I'm doing a program that upload employees to a site or plant, my idea it's fill with 1 form and in the textbox add more of one employee, here is an example to how should it work if i write employee id.
Example:

employee id (Textbox): 9991, 9992, 8873
Site: US

So when I click on Accept_Button it should save the data in database like this:

Here it's the code I have
HTML:

<div class="item">  
   <label for="Id">ID<span>*</span></label>  
   <input id="Id" type="text" runat="server" required="required"/>   
`</div>  
 <div class="item">  
    <label for="Site">SITE<span>*</span></label>  
    <input id="Site" type="text" runat="server" required="required"/>  
 </div>  

C#:

using (SqlConnection sqlCon = new SqlConnection(connectionString))  
{  
     sqlCon.Open();  
     string query = "INSERT INTO Employees (EID, Site) VALUES (@EID,@EID)";  
            SqlCommand sqlCmd = new SqlCommand(query, sqlCon);  
            sqlCmd.Parameters.AddWithValue("@EID", Id.Value);  
            sqlCmd.Parameters.AddWithValue("@Site", Site.Value);  
            sqlCmd.ExecuteNonQuery();  
}  

I try to use a Split function but I don't know how to add it in my program.
I have this but I don't know how add it or use it:

    var sep = new string[] { ", " };  
    string[] subs = Id.Value.Split(sep, StringSplitOptions.None);  

Answer 1

Try something like this:

using (SqlConnection sqlCon = new SqlConnection(connectionString))
{
   sqlCon.Open();
   string query = "INSERT INTO Employees (EID, Site) VALUES (@EID, @Site)";
   SqlCommand sqlCmd = new SqlCommand(query, sqlCon);
   foreach( var id in Id.Value.Split(','))
   {
      sqlCmd.Parameters.Clear();
      sqlCmd.Parameters.AddWithValue("@EID", id.Trim());
      sqlCmd.Parameters.AddWithValue("@Site", Site.Value.Trim());
      sqlCmd.ExecuteNonQuery();
   }
}