private void button2_Click(object sender, EventArgs e)
{
    if (OrderIdTb.Text == "" || CustId.Text == "" || CustName.Text == "" || TotAmount.Text == "")
    {
        MessageBox.Show("Fill The data Correctly");
    }
    else                  
    {
        Con.Open();
        SqlCommand cmd = new SqlCommand("Insert into ProductTbl Values("   OrderIdTb.Text   ","   CustId.Text   ","   CustName.Text   ","   orderdate.Text   ","   TotAmount.Text   ")", Con) ;
        cmd.ExecuteNonQuery();
        MessageBox.Show("Order Added  Successfully ");
        populate();
        Con.Close();
                    
        try
        {

        }
        catch 
        {
                
        }
    }
}

CodePudding user response：

it's good habit to write finally block and within that you have close all opened sql connections and try to use Using loop to run the query.

Eg:

SqlConnection sqlconn= null;
   SqlCommand sqlcmd= null;
   SqlTransaction sqlTrans= null;
   SqlDataReader sqlReader= null;
   try
   {
      sqlconn = new SqlConnection("conn string");
      sqlconn.Open();
---- Query ---
---- Query ---
---- Query ---
sqlconn.Close()
   }
catch(exception ex)
{
}
finally
{
if(sqlReader !=null)
{
sqlReader.close();
sqlReader = null;
}
if(sqlTrans != null)
{
sqlTrans.Dispose();
sqlTrans = null;
}
if(sqlcmd != null)
{
sqlcmd.Dispose();
sqlcmd = null;
}
if( sqlconn != null)
{
sqlconn.Close();
sqlconn = null;
}
}

CodePudding user response：

Create a new connection for each function. Don't try to reuse a database connection, it always ends badly.

   using (var con = new SqlConnection(....)){
        con.Open();
        SqlCommand cmd = new SqlCommand("Insert into ProductTbl Values("   OrderIdTb.Text   ","   CustId.Text   ","   CustName.Text   ","   orderdate.Text   ","   TotAmount.Text   ")", Con) ;
        cmd.ExecuteNonQuery();
        MessageBox.Show("Order Added  Successfully ");
        populate();
   } //Then end of the using block closes the connection safely, even if there is an error.