problem in dataset

Question

 tXtSearch.tex="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.