You can easily add the Product Dimension and Product Color in the query same like the Product Name with the
"AND"
string ProductName = cboproductname.SelectedItem.ToString();
string ProductDimension= combobox2.SelectedItem.ToString();
string ProductColor= combobox3.SelectedItem.ToString();
string sql = "SELECT ProductNo FROM RawMat WHERE ProductName=@PName AND ProductDimension=@PDimension AND ProductColor=@PColor";
SqlCommand cmd = new SqlCommand(sql, cn);
cmd.Parameters.AddWithValue("@PName", ProductDimension);
cmd.Parameters.AddWithValue("@PDimension", ProductColor);
cmd.Parameters.AddWithValue("@PColor", ProductName);
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
txtproductno.Text = dr["ProductNo"].ToString();
}
dr.Close();
Mark it as solution, If it resolved your issue.
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlparameter.aspx[
^]