title: save a decimal value in database c#
body: <p>I am trying to save a value from text box into sql database. I am having the error as shown on the picture. my code below:</p>
  
  <pre><code>    public void datastore()
          {
              string Blerje, Shitje, Data;
              Blerje = usdollar_buy.Text;
              Shitje = usdollar_sell.Text;
              Data = dateTimePicker.Text;
  
              try
              {
                  string constring = "Data Source=DELL;Initial Catalog=login_register;Integrated Security=True";
  
                  /* Declaring Connection Variable */
                  SqlConnection con = new SqlConnection(constring);
                  String sql = "INSERT into [login_register].[dbo].[BlerjeShitje] values ('" + Blerje + "','" + Shitje + "','" + Data + "')";
  
                  /* Checking Connection is Opend or not If its not open the Opens */
                  if (con.State != ConnectionState.Open)
                      con.Open();
  
                  SqlCommand cmd = new SqlCommand(sql, con);
  
                  /* Executing Stored Procedure */
                  cmd.ExecuteNonQuery();
                  con.Close();
                  MessageBox.Show("Te dhenat u ruajten ne databaze");
              }
              catch (Exception ex)
              {
                  MessageBox.Show(ex.Message);
              }
          }
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/7fFWr.png" alt="enter image description here"></p>