How to disable checkbox after insert the value in data base

Question

i'm trying this code, actually i'm trying to make bed booking.

 

please help me how can i do

protected void btnSave_Click(object sender, EventArgs e)
{
string bednumber, Bedstatus;
try
{
if (chkkk.Checked == true)
{
bednumber = "First Floor 201";
}
else if (chk1.Checked == true)
{
bednumber = "First Floor 202";
}
else if (chk2.Checked == true)
{
bednumber = "First Floor 203";
}
else if (chk3.Checked == true)
{
bednumber = "First Floor 204";
}
else if (chk4.Checked == true)
{
bednumber = "First Floor 205";
}
else if (chk5.Checked == true)
{
bednumber = "First Floor 206";
}
else if (chk6.Checked == true)
{
bednumber = "First Floor 207";
}
else if (chk7.Checked == true)
{
bednumber = "First Floor 208";
}
else
bednumber = "Non";
if (ChkActive.Checked)
{
Bedstatus = "Booked";
}
else
Bedstatus = "Booked";
conn.Open();
SqlCommand cmd = new SqlCommand("IF NOT EXISTS(SELECT * FROM BedBooking WHERE BedNumber = '" + bednumber + "')INSERT INTO BedBooking(PatientName, BedNumber) VALUES('" + txtName.Text + "','" + bednumber + "')", conn);
cmd.ExecuteNonQuery();
SqlCommand cmd1 = new SqlCommand("IF NOT EXISTS(SELECT * FROM AddBedNumber WHERE BedNumber = '" + bednumber + "') INSERT INTO AddBedNumber(BedNumber, Active) VALUES('" + bednumber + "','" + Bedstatus + "')", conn);
cmd1.ExecuteNonQuery();
conn.Close();
Response.Write("<script language='javascript'>alert('Thank you !!! Your Booking has been Sucessfully!!')</script>");
}
catch (Exception ex)
{
}
}