How do I access the underlying DataTable in an ASP.NET GridView

1
votes

I have a paginated GridView on an ASP.NET page. In the DataBound event of the GridView control, I am attempting to update the OnClick event of each cell in the row to window.open() a new page using a field in the underlying DataTable that is not displayed in the GridView. However, the GridView DataSource propety is null, as is the GridViewRow DataItem property. The GridView's DataKeys has a Count of 0. The paginated DataSet has 20 rows and is being rendered properly, I just can't find the underlying data to pull the ID needed for the window.open() call.

I have followed asp.net's guide when constructing my page:

  1. Creating a data access layer
  2. Creating a business access layer
  3. Displaying Data with ObjectDataSource

So I have a DAL -> BLL -> ObjectDataSource -> GridView. The ID column is being hidden in the GridView:

    <asp:GridView ID="pdfdocuments" runat="server" AllowPaging="True" 
        AutoGenerateColumns="False" DataSourceID="pdfods" PageSize="20" 
        ondatabound="pdfdocuments_DataBound">
        <PagerSettings Mode="NumericFirstLast" />
        <Columns>
            <asp:BoundField DataField="pdf_id" HeaderText="pdf_id" InsertVisible="False" 
                ReadOnly="True" SortExpression="pdf_id" Visible="False" />
...
        </Columns>
        <HeaderStyle BackColor="#FFCC99" />
        <AlternatingRowStyle BackColor="#FFFFCC" />
    </asp:GridView>

How do I access the pdf_id value in the underlying DataTable?

2
asp.netgridviewdatatable

2 Answers

2
votes

Try accessing GridView.DataSourceObject in the RowDataBound event.

Unless there is some requirement to use javascript window.open it is probably better to use an anchor tag with a target like the following code:

<asp:GridView ID="GridView1" runat="server" DataSourceID="ODS1"
    OnRowDataBound="GridView1_RowDataBound" AutoGenerateColumns="False">
    <Columns>
        <asp:HyperLinkField DataTextField="FieldName" DataNavigateUrlFields="FieldID" DataNavigateUrlFormatString="somePage.aspx?id={0}" Target="_blank" />
    </Columns>
</asp:GridView>

If you have to execute JavaScript you can still do it without accessing the underlying DataSourceObject directly using a TemplateField:

<asp:GridView ID="GridView1" runat="server" DataSourceID="ODS1"
    OnRowDataBound="GridView1_RowDataBound" AutoGenerateColumns="False">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <a href='javascript:window.open(<%# Eval("FieldID") %>);'><%#Eval("FieldName")%></a>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
1
votes

I agree with D-Mac to use RowDataBound event. But instead of using GridView.DataSourceObject try to access the row's DataItem property. 

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    DataRowView rowView = e.Row.DataItem as DataRowView;
    if (rowView != null)
    {
        //Check if the execution reach this pont
        object pdf_id = rowView["pdf_id"];
    }
}

You can find an example here