multiple select to delete rows in gridview

for(int i=0;i<gridview1.rows.count;i++)
{
   //Find checkbox
   CheckBox Chk=(CheckBox)Gridview1.Rows[i].FindControl("ChkSelect");
   if(Chk.checked)
   {
     //Select the corresponding rows details
     //delete query write here
   }
}

protected void btnDelete_Click(object sender, EventArgs e)
{
//Create String Collection to store 
//IDs of records to be deleted 
  StringCollection idCollection = new StringCollection();
  string strID = string.Empty;

  //Loop through GridView rows to find checked rows 
   for (int i = 0; i < GridView1.Rows.Count; i++)
   {
    CheckBox chkDelete = (CheckBox)
       GridView1.Rows[i].Cells[0].FindControl("chkSelect");
            if (chkDelete != null)
            {
                if (chkDelete.Checked)
                {
                 strID = GridView1.Rows[i].Cells[1].Text;
                 idCollection.Add(strID);
                }
            }
        }

        //Call the method to Delete records 
        DeleteMultipleRecords(idCollection);

        // rebind the GridView
        GridView1.DataBind();
    }
private void DeleteMultipleRecords
                            (StringCollection idCollection)
{
//Create sql Connection and Sql Command
 SqlConnection con = new SqlConnection(strConnection);
 SqlCommand cmd = new SqlCommand();
 string IDs = "";

foreach (string id in idCollection)
{
  IDs += id.ToString() + ",";
}
          try
            {
               string strIDs = 
                IDs.Substring(0, IDs.LastIndexOf(","));
                   string strSql = "Delete from Details 
                           WHERE ID in (" + strIDs + ")";
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = strSql;
                cmd.Connection = con;
                con.Open();
                cmd.ExecuteNonQuery();
            }
            catch (SqlException ex)
            {
                string errorMsg = "Error in Deletion";
                errorMsg += ex.Message;
                throw new Exception(errorMsg);
            }
            finally
            {
                con.Close();
            }
}