Filter from Gridview

see here it will hlp u...



http://www.asp.net/web-forms/overview/presenting-and-managing-data/model-binding/sorting-paging-and-filtering-data

like as


 public DataTable Dt_Branch
        {
            get
            {
                object temp = ViewState["Dt_Branch"];
                return temp == null ? null : temp as DataTable;
            }

            set
            {
                ViewState["Dt_Branch"] = value;
            }

        }

page_load
{
  BindGridView();

}
protected void BindGridView()
        {
            DataView EmpDataView = new DataView();
            EmpDataView = Dt_Branch.DefaultView;


            GrdBranch.PageSize = pageSize;
            totalRowCount = EmpDataView.Count;
            GrdBranch.DataSource = EmpDataView;
            GrdBranch.DataBind();
        }
btnsearchclick
{
  if (txt_Search.Text.Trim().Length > 0)
                {                   
                    Dt_Branch .DefaultView.RowFilter = "name  Like '" + txt_Search.Text.Trim().Replace("'", " ") + "%'  ";
                    //GrdBranch.DataSource = Dt_Branch.DefaultView;
                    //GrdBranch.DataBind();
                    BindGridView();
                }
}

store data in datatable with viewstate once and then bind gridview.
and on filter.
use datatable.select()
and bind gridview again