A parameter is passed through drop down show result in grid

Question

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

{

try

{

con.Open();

query = "select * from OA_PlayerBat where Team_ID ='" + ddTeam.SelectedItem + "'";

SqlCommand cmd = new SqlCommand(query, con);

SqlDataAdapter da = new SqlDataAdapter(cmd);

DataSet ds = new DataSet();

da.Fill(ds);

grdResult.DataSource = ds;

grdResult.DataBind();

con.Close();

}

this is a drop-down list here user has to select the team to show the results of that team in a grid view. 

I have made a stored procedure and i am unable to pass the user selected drop down value there.