private void btnsearch_Click(object sender, EventArgs e)
 {
     if (dtdsearchbydate.Text.Length > 0)
     {
         DataTable dt = new DataTable();
         dt = blod.searchbydate(Convert.ToDateTime(dtdsearchbydate.Text));
         if (dt.Rows.Count > 0)
         {
             dataGridView1.DataSource = dt;
         }
         else
         {
             MessageBox.Show("Product Does Not Found");
         }
     }
     else
     {
         MessageBox.Show("Please Enter Text Box");
     }
 }