binding with datatset

Question

 
tXtSearch.Text='300*400'

 private void tXtSeach_TextChanged(object sender, EventArgs e)

        {

            try

            {

               if (dgv_Search.DataSource.Equals(prodmastBindingSource))

                {

              tXtSeach.Text.Trim().ToUpper());

                  prodmastBindingSource.Filter = String.Format("Description like '%{0}%'", tXtSeach.Text.Trim().ToUpper());

                }

            }

            catch { } 

        }

Error in Like operator: the string pattern '300*400%' is invalid.