Fill a grid view by a drop down list - asp.net

Question

I have a drop down list ; a sqldatasource and a gridview .
I want to fill the grid view by the choice in the drop down list.
How can i implement this fill ?
Thanks
My question is not a duplicate of this Click
because it want to populate a drop down list inside the grid view instead my question is : by a choice of a drop down list , fill a grid view.
EDIT (Because i am in negative rep.) :
What i have tried
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.BindData();
}
}
private void BindData()
{
string query = "SELECT top 10 * FROM Customers";
SqlCommand cmd = new SqlCommand(query);
gvCustomers.DataSource = GetData(cmd);
gvCustomers.DataBind();
}
private DataTable GetData(SqlCommand cmd)
{
string strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection con = new SqlConnection(strConnString))
{
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
return dt;
}
}
}
}

Answer 1

aspx page
<asp:DropDownList runat="server" ID="drp" AutoPostBack="true" OnSelectedIndexChanged="drp_SelectedIndexChanged"></asp:DropDownList>
<asp:GridView runat="server" ID="grd" AutoGenerateColumns="true"></asp:GridView>
code behind of aspx
protected void drp_SelectedIndexChanged(object sender, EventArgs e)
{
BindGrid();
}
private void BindGrid()
{
grd = dataSource;
grd.DataBind();
}
Bind grid on selection index change event of dropdown.