How to rectify this kind of error while inserting the data in to database

Question

Unclosed quotation mark after the character string ')'.

Code:

SqlConnection con = new SqlConnection("Data Source=localhost;Initial Catalog=dataentry;Integrated Security=True;Pooling=False");

private void btnsava_Click(object sender, EventArgs e)
{
    con.Open();
    SqlDataAdapter sda = new SqlDataAdapter(" Insert Into Data Entr (Id,Name,Gender,Age,Salary,Tax) Values ('" + textBox1.Text + "','" + textBox2.Text + "','" + comboBox1 + "'," + textBox3.Text + "','" + textBox4.Text + "','" + textBox5.Text + "')" ,con);
    sda.SelectCommand.ExecuteNonQuery();
    con.Close();
    MessageBox.Show("Saved sucessful");
}