Here is working code:
Form 3
DialogResult dialogResult = MessageBox.Show("Are you sure you want to insert data", "Data insert Confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Information);
if (dialogResult == DialogResult.Yes)
{
cmd = new OleDbCommand("update Medicine_Available_Detail set [Availability]=[Availability]-@Quantity where [Medicine_Name]=@Medicine_Name", con);
cmd.Parameters.AddWithValue("@Quantity", quantity);
cmd.Parameters.AddWithValue("@Medicine_Name", medicinename);
Form1 frm = new Form1();
DialogResult dr = frm.ShowDialog();
if (dr != DialogResult.OK)
{
return;
}
con.Open();
int n = cmd.ExecuteNonQuery();
con.Close();
MessageBox.Show("Record Updated Successfully");
userlist();
try
{
string query = "select Medicine_Name,Availability from Medicine_Available_Detail where Medicine_Name='" + medicinename + "'";
using (cmd = new OleDbCommand(query, con))
{
con.Open();
using (OleDbDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
string Medicine_Name = (string)reader["Medicine_Name"];
int Availability = (int)reader["Availability"];
MessageBox.Show("Total stock of: " + medicinename + " is now: " + Availability + " ");
}
reader.Close();
}
con.Close();
}
dataGridView1.Refresh();
}
catch (Exception ex)
{
}
form 1
private void button1_Click_1(object sender, EventArgs e)
{
this.txtinput.MaxLength = 4;
cmd = new OleDbCommand("update Login set Sales_count= IIF(IsNull(Sales_count), 0, Sales_count) + 1, [To_Date]=Date() where [Unique_No]=@Unique_No", con);
cmd.Parameters.AddWithValue("@Unique_No", txtinput.Text);
con.Open();
int n = cmd.ExecuteNonQuery();
if (n == 0)
{
MessageBox.Show("Invalid Unique No.");
}
else
{
this.DialogResult = DialogResult.OK;
}
con.Close();
}