dataGridView1.DataSource = bsUebersicht;

 private void textBox1_TextChanged(object sender, EventArgs e)
        {
            try
            {
bsUebersicht.Filter = "Nummer " + string.Format(" LIKE '%{0}%'", textBox1.Text);
}
catch {}
}

        private void Suchfeld_TextChanged(object sender, EventArgs e)
        {
            Suchfilter(true, Suchfeld.Text);
        }

        private void Suchfilter(bool fragment, string Suchbegriff)
        {
            dt_Geraete.DefaultView.RowFilter = string.Format("[_RowString] LIKE '%{0}%'", Suchfeld.Text);
        }

        private void Suchfeld_anlegen()
        {
            if (ColumnExistsInTable(dt_Geraete, "_RowString") == true)
                dt_Geraete.Columns.Remove("_RowString");

            DataColumn dcRowString = dt_Geraete.Columns.Add("_RowString", typeof(string));
            foreach (DataRow dataRow in dt_Geraete.Rows)
            {
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < dt_Geraete.Columns.Count - 1; i++)
                {
                    sb.Append(dataRow[i].ToString());
                    sb.Append("\t");
                }
                dataRow[dcRowString] = sb.ToString();
            }

            SQL_GeraeteDataGrid.Columns["_RowString"].Visible = false;
        }

        private static bool ColumnExistsInTable(DataTable dataTable, string columnName)
        {
            return dataTable.Columns.IndexOf(columnName) != -1;
        }