I want to insert null
parameter in some values, but I get the following error :
System.NullReferenceException: 'Object reference not set to an instance of an object.' System.Windows.Forms.ListControl.SelectedValue.get returned null.
The program is a Windows Forms
application, and the code is as follows:
using (var context = new SamenEntities())
{
person ppp = new person()
{
id = textBox1.Text.Trim(),
name = textBox2.Text.Trim(),
family = textBox3.Text.Trim(),
birth_date = dateTimePicker1.Value,
birth_provice = Convert.ToInt32(comboBox1.SelectedValue.ToString()),
note = richTextBox1.Text.Trim(),
img_personal = ImageToByteArray(pictureBox1.Image),
date_register = DateTime.Now
};
context.persons.Add(ppp);
context.SaveChanges();
}
How to enter null
value or enter default value from SQL server?