Question

I am trying to nest one gridview within another, but I cannot get the data to populate in the second grid view. I am getting an error when trying to set the data source of the second data grid (saying it is null). Can anyone help?
Here is the aspx page:

<div id="divSource" runat="server" align="center">
<asp:GridView ID="Source" runat="server" AutoGenerateColumns="False" DataKeyNames="sourceLineItem"  CSSClass="viewSourceGrid" OnRowDataBound="PopulateDateCodes">
    <Columns>
        <asp:TemplateField InsertVisible="False" HeaderStyle-Width="70px">
            <ItemTemplate>
                <asp:Label CssClass="sourceHeader" runat="server" Text= '<%# "Source: " + (Container.DataItemIndex + 1).ToString() %>'> </asp:Label>
            </ItemTemplate>
        </asp:TemplateField> 
        <asp:BoundField DataField="nfdBroker" HeaderText="NFD/Broker" InsertVisible="False" ReadOnly="True" SortExpression="nfdBroker" />
        <asp:BoundField DataField="locationDescription" HeaderText="Material Location" SortExpression="materialLocation" />
        <asp:BoundField DataField="origPkg" HeaderText="Original Packaging?" SortExpression="origPkg" />
        <asp:BoundField DataField="oemCC" HeaderText="OEM C of C? " InsertVisible="False" ReadOnly="True" SortExpression="oemCC" />
        <asp:BoundField DataField="minBuyQty" HeaderText="Minimum Buy Qty" SortExpression="minBuyQty" />
        <asp:BoundField DataField="deliveryInfo" HeaderText="Delivery" SortExpression="delUOM" />

        <asp:TemplateField InsertVisible="False" HeaderText="Date Codes" >
            <ItemTemplate>               
                <asp:GridView ID="DateCodeGrid" runat="server" InsertVisible="False" DataKeyNames="dateCode"  CSSClass="viewSourceGrid" >
                    <Columns>
                        <asp:BoundField DataField="dateCode" SortExpression="dateCode">
                            <ItemStyle Width="20%" />
                        </asp:BoundField>
                    </Columns>
                </asp:GridView>
            </ItemTemplate>
        </asp:TemplateField>

    </Columns>
</asp:GridView>

and then here is the code behind:

    public partial class Controls_ViewSource : System.Web.UI.UserControl
{
    //Set the Source Line Item
    public int SourceLineItem { get; set; }

    protected void Page_Load(object sender, EventArgs e)
    {
        this.SourceLineItem = SourceLineItem;
        RequestDB db = new RequestDB();
        DataSet sources = db.GetSource(int.Parse(Request.QueryString["requestNumber"]), SourceLineItem);
        Source.DataSource = sources;
        Source.DataBind();

    }

    protected void PopulateDateCodes(object sender, GridViewRowEventArgs e)
    {
        RequestDB db = new RequestDB();
        int index = e.Row.RowIndex;
        GridView gv = (GridView)Source.Rows[0].FindControl("DateCodeGrid");
        //int sourceLineItem = int.Parse(Source.DataKeyNames[0].ToString());
        //Response.Write(Source.DataKeyNames[0].ToString());
        DataSet dateCodes = db.GetDateCodes(71);
        gv.DataSource = dateCodes;
        gv.DataBind();

    }
}

Answer 1

You would need to find the nested grid view in the row that is being data bound:

GridViewRow row = e.Row;

You need to make sure you are only doing this for data rows, not header or footer rows:

if(row.RowType == DataControlRowType.DataRow)
{
  // Find the nested grid view
  GridView nested = (GridView)row.FindControl("DateCodeGrid");

  // The rest of your code for binding the nested grid view follows here
}