How to reuse SqlCommand parameter through every iteration?

Question

I want to implement a simple delete button for my database. The event method looks something like this:

private void btnDeleteUser_Click(object sender, Event         


        

Answer 1

Error is because you are adding the same parameter again and again in each iteration of the loop.

I would move that code to a seperate method so that i can call it from multiple places as needed.

public bool DeleteUser(int userId)
{
    string connString = "your connectionstring";
    try
    {
      using (var conn = new SqlConnection(connString))
      {
        using (var cmd = new SqlCommand())
        {
            cmd.Connection = conn;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "DELETE FROM tbl_Users WHERE userID = @id";
            cmd.Parameters.AddWithValue("@id", userId);
            conn.Open();
            cmd.ExecuteNonQuery();
            return true;
        }
      }
    }
    catch(Exception ex)
    {
      //Log the Error here for Debugging
      return false;
    }

}

Then call it like this

 foreach (DataGridViewRow row in dgvUsers.SelectedRows)
 {
   int selectedIndex = row.Index;
   if(dgvUsers[0,selectedIndex]!=null)
   {
     int rowUserID = int.Parse(dgvUsers[0,selectedIndex].Value.ToString());
     var result=DeleteUser(rowUserID)
   }
   else
   {
      //Not able to get the ID. Show error message to user
   } 
 }