private void productForm_Load(object sender, EventArgs e)
{
CategoryManager categoryManager = new CategoryManager();
ComapnyManager comapnyManager = new ComapnyManager();
categoryComboBox.DataSource = categoryManager.AllData();
categoryComboBox.DisplayMember = "CategoryName";
categoryComboBox.ValueMember = "CategoryID";
categoryComboBox.SelectedValue = -1;
companyComboBox.DataSource = comapnyManager.AllData();
companyComboBox.DisplayMember = "CompanyName";
companyComboBox.ValueMember = "CompanyID";
companyComboBox.SelectedValue = -1;
reorderTextBox.Text = "0";
}
