protected void btnDocsAdd_Click(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();

        lblDocsErrorMsg.Text = "";
        if (ViewState["DocsTable"] == null)
        {
            dt.Columns.Add("Nature  of Document");
            dt.Columns.Add("Sr. No. From");
            dt.Columns.Add("Sr. No. To");
            dt.Columns.Add("Total Number");
            dt.Columns.Add("Cancelled");
        }
        else
        {
            dt = (DataTable)ViewState["DocsTable"];
        }

        DataRow dr = dt.NewRow();



        dr["Nature  of Document"] = ddlDocsNatureOfDoc.SelectedItem.Text.ToString();
        dr["Sr. No. From"]        = txtDocsSrNoFrom.Text.Trim();
        dr["Sr. No. To"]          = txtDocsSrNoTo.Text.Trim();
        dr["Total Number"]        = txtDocsTotalNo.Text.Trim();
        dr["Cancelled"]           = txtDocsCancelled.Text.Trim() == "" ? "0" : txtDocsCancelled.Text.Trim();
        dt.Rows.Add(dr);
        ViewState["DocsTable"] = dt;
        GridDocs.DataSource    = dt;
        GridDocs.DataBind();
        ClearDocs();
    }
 protected void GridDocs_RowCommand(object sender, GridViewCommandEventArgs e)
 {
     if (e.CommandName == "DeleteRecords")
     {
         DataTable DocsTable = (DataTable)ViewState["DocsTable"];
         DocsTable.Rows.RemoveAt(int.Parse(e.CommandArgument.ToString()));
         ViewState["DocsTable"] = DocsTable;
         GridDocs.DataSource    = DocsTable;
         GridDocs.DataBind();
     }
 }
    protected void clearGrid()   // clear all grid or view state all tab data
    {
        grdB2B.DataSource = null;
        grdB2B.DataBind();
        GridB2cl.DataSource = null;
        GridB2cl.DataBind();
        GridB2cs.DataSource = null;
        GridB2cs.DataBind();
        GridCdnr.DataSource = null;
        GridCdnr.DataBind();
        GridCdnur.DataSource = null;
        GridCdnur.DataBind();
        GridExp.DataSource = null;
        GridExp.DataBind();
        GridAt.DataSource = null;
        GridAt.DataBind();
        GridAtAdj.DataSource = null;
        GridAtAdj.DataBind();
        GridHsn.DataSource = null;
        GridHsn.DataBind();
        GridExeMp.DataSource = null;
        GridExeMp.DataBind();
        GridDocs.DataSource = null;
        GridDocs.DataBind();

        ViewState["B2BTable"]   = null;
        ViewState["B2ClTable"]  = null;
        ViewState["B2CSTable"]  = null;
        ViewState["CDNRTable"]  = null;
        ViewState["CDNURTable"] = null;
        ViewState["ExpTable"]   = null;
        ViewState["AtTable"]    = null;
        ViewState["AtAdjTable"] = null;
        ViewState["HsnTable"]   = null;
        ViewState["ExeMpTable"] = null;
        ViewState["DocsTable"]  = null;

        ClearB2B();
        ClearB2cl();
        ClearB2cs();
        ClearCdnur();
        ClearExp();
        ClearAt();
        ClearDocs();
        ClearAtAdj();
        ClearExeMp();
        ClearHsn();
        ClearCdnr();
    }