Check if Date Already Existed

Question

I have my code here i wish check if the reservation date is already not available

BTW I have a button so after clicking it one time " It said Available " but after clicking it again it will not show anything

 

can someone please help me or correct what if what is wrong with my code

ty for those who are willing help :)

 

DataSet myDataSet = new DataSet();

try

{

connection.Open();

string strAccessSelect = "select count(*) from Borrow where DUEDATE = '" + due3.Text + "' AND BOOK_NUMBER = '" + bno.Text + "'";

OleDbCommand myAccessCommand = new OleDbCommand(strAccessSelect, connection);

OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand);

connection.Open();

myDataAdapter.Fill(myDataSet, "Borrow");

}

catch (Exception ex)

{

Console.WriteLine("Error: Failed to retrieve the required data from the DataBase.\n{0}", ex.Message);

return;

}

finally

{

connection.Close();

}

DataTable dt = myDataSet.Tables[0];

if (dt != null)

{

if (int.Parse(dt.Rows[0][5].ToString()) > 0)

{

MessageBox.Show(" Not Available");

}

else

{

MessageBox.Show(" Available");

}

}