Cannot convert array list to string
<p>I had Repeater which bind method this method retrieve data from data base by stored procedure when Model_Id pass to this method it retrieve data also user can repeat repeater more than once when user select DDL more than once.I did the code and I add all Model_Ids which user select from DDL in array list but error appear </p>

<p>Cannot convert array list to string value:</p>

<pre><code>protected void Add_Click(object sender, ImageClickEventArgs e)
{
    ArrayList Array = new ArrayList();
    Array.Add(DDLModel.SelectedValue);
    DLHome.DataSource = Cls.GetModelName(Array);
    DLHome.DataBind();
}

public DataTable GetModelName(string Model_Id)
{
    using (SqlConnection conn = Connection.GetConnection())
    {
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = conn;
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.CommandText = "GetComparisonModel";
        SqlParameter ParentID_Param = cmd.Parameters.Add("@Model_Id", SqlDbType.Int);
        ParentID_Param.Value = Model_Id;
        DataTable dt = new DataTable();
        SqlDataAdapter da = new SqlDataAdapter();
        da.SelectCommand = cmd;
        da.Fill(dt);
        return dt;
    }
}
</code></pre>
