private void button1_Click(object sender, EventArgs e)
{
String exeStr = "DELETE FROM ReturnedHistory ";
new Class_CRUDdb().exeData(exeStr);
Form_Statistics.refeshLichsuTraSach();
}
private void button2_Click_1(object sender, EventArgs e)
{
//statics
ColorClear();
button2.BackColor = Color.CadetBlue;
form_Statistics1.BringToFront();
Form_Statistics.refeshSachDaMuon();
Form_Statistics.refeshLichsuTraSach();
Form_Statistics.refeshSinhvienQuahan();
}