How Do I Check A Row For Sql C#

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C#

SQL

private void button2_Click(object sender, EventArgs e)
        { 
           if (textBox1.Text.Trim().Length == 0)
                MessageBox.Show("Please fill this area first");
            
            else
            {
                SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=AG_DB;Integrated Security=True");
                SqlDataAdapter sda = new SqlDataAdapter("SELECT * FROM Musteri where ID = '" + textBox1.Text + "'", con);
                DataTable dt = new DataTable();
                sda.Fill(dt);
                textBox1.Text = dt.Rows[0][0].ToString();
                textBox2.Text = dt.Rows[0][1].ToString();
                textBox3.Text = dt.Rows[0][2].ToString();
                textBox4.Text = dt.Rows[0][3].ToString();
                textBox5.Text = dt.Rows[0][4].ToString();
                textBox6.Text = dt.Rows[0][5].ToString();
                textBox7.Text = dt.Rows[0][6].ToString();
                textBox8.Text = dt.Rows[0][7].ToString();
            }
        }

this is my code that reads data from sqlserver and fills all textboxes using textbox1. I need an exception that warns me when i write something on textbox1 that doesn't exist on my sql ID Column. How can i do that?