Problem in Binding GridView when no data is present

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C#

ASP.NET

web_development

Hi all,

i am binding gridview from the view when data is present and if no data is presnt in view i have to bind it from a table..

it works fine when data is present in view....but when view is blank Eval function throws exception.

following is the code for the GridView:-

<asp:GridView ID="grid_Demand" runat="server" Width="80%" DataKeyNames="Book_Depot_Id_N" 
                    AutoGenerateColumns="False" CellPadding="4" ForeColor="#333333" 
                    GridLines="None">
                    <RowStyle BackColor="#EFF3FB" />
                <Columns>
                <asp:TemplateField>
                <HeaderTemplate>Depot Id</HeaderTemplate>
                <HeaderStyle HorizontalAlign="Center" />
                <ItemStyle HorizontalAlign="Center" />
                <ItemTemplate>
                <%# Eval("Book_Depot_Id_N")%>
                </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                <HeaderTemplate>Depot Name</HeaderTemplate>
                <HeaderStyle HorizontalAlign="Center" />
                <ItemStyle HorizontalAlign="Center" />
                <ItemTemplate>
                <%# Eval("Book_Depot_Name_V") %>
                </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                <HeaderTemplate>Govt. Supply</HeaderTemplate>
                <HeaderStyle HorizontalAlign="Center" />
                <ItemStyle HorizontalAlign="Center" />
                <ItemTemplate>
                <asp:TextBox ID="txtGovt" runat="server" CssClass="textfield1" Text='<%# Eval("Govt_Supply_Qty_N") %>'></asp:TextBox>
                </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                <HeaderTemplate>Private Supply</HeaderTemplate>
                <HeaderStyle HorizontalAlign="Center" />
                <ItemStyle HorizontalAlign="Center" />
                <ItemTemplate>
                <asp:TextBox ID="txtPvt" runat="server" CssClass="textfield1" Text='<%# Eval("Pvt_Supply_Qty_N") %>'></asp:TextBox>
                </ItemTemplate>
                </asp:TemplateField>
                </Columns>
                    <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                    <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                    <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <EditRowStyle BackColor="#2461BF" />
                    <AlternatingRowStyle BackColor="White" />
                </asp:GridView>

and the following is the code for code-behind:-

mEntity.BOOK_CLASS_ID_N = Convert.ToInt32(ddlclass.SelectedValue.ToString().Trim());
        mEntity.Book_Id_N = Convert.ToInt32(ddlbookcode.SelectedValue.ToString().Trim());
        dt = mAction.LoadWithWhereClause("PSS_GET_PRODUCTION_DEMAND_V", Constant.BOOK_CLASS_ID_N + " = " + mEntity.BOOK_CLASS_ID_N + " AND " + Constant.Book_Id_N + " = " + mEntity.Book_Id_N + " AND " + Constant.FinYear_Id_N + " = " + UtilsSession.GetCurrentFinYearId(), Constant.Book_Id_N);
        if (dt.Rows.Count > 0)
        {
            // dt = mAction.Load(Constant.PSS_BOOK_DEPOT_T);
            grid_Demand.DataSource = dt;
            grid_Demand.DataBind();
        }
        else
        {
            dt = mAction.Load(Constant.PSS_BOOK_DEPOT_T);
            grid_Demand.DataSource = dt;
            grid_Demand.DataBind();
        }