Question

I have a GridView with an anonymous type. I need to check the value in a cell and highlight that cell if a condition is met. The problem is, I always get an empty string when I try to pull data out of the row’s cells. I have successfully highlighted all the cells and I have checked in the Visual Studio 2010 debugger and confirmed that the Row has data (the row’s DataItem has the values I need). This is happening on a PostBack, I’m not sure if that’s a problem or not.

Here is the code and solutions I’ve tried:

protected void grvValidCourses_RowDataBound(Object sender, GridViewRowEventArgs e) {
 if (e.Row.RowType == DataControlRowType.DataRow) {
  String str = e.Row.Cells[6].Text.ToString(); // empty string
  Label lbl = (Label) grvValidCourses.FindControl("lblEndDate"); // null
  DataRowView rowView = (DataRowView)e.Row.DataItem; // exception about casting anonymous type

What’s going on here? Why can’t I get data from the cells?

Markup for GridView:

 <asp:GridView ID="grvValidCourses" runat="server" Width="790px" OnRowCancelingEdit="grvValidCourses_RowCancelingEdit"
                    OnRowEditing="grvValidCourses_RowEditing" OnRowUpdating="grvValidCourses_RowUpdating" OnRowDeleting="grvValidCourses_RowDeleting"
                    AutoGenerateColumns="False" OnSelectedIndexChanged="grvValidCourses_SelectedIndexChanged"
                    OnRowDataBound="grvValidCourses_RowDataBound" >
                    <Columns>
                        <asp:CommandField ShowEditButton="True" EditText="Edit" UpdateText="Update |" />
                        <asp:TemplateField ShowHeader="False">
                             <ItemTemplate>
                               <asp:LinkButton ID="lbnDelete" runat="server" CausesValidation="False" CommandName="Delete"
                                    Text='<%# (Eval("active") == null ? "Delete" : ((Eval("active").ToString() == "0" ? "Restore" : "Delete"))) %>' />  
                             </ItemTemplate>
                        </asp:TemplateField>
                        <asp:CommandField ShowSelectButton="True" SelectText="Details" />
                        <asp:TemplateField HeaderText="Training Name" SortExpression="coursename">
                            <EditItemTemplate>
                                <asp:Label ID="Label1" runat="server" Text='<%# Eval("coursename") %>'></asp:Label>
                            </EditItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Label2" runat="server" Text='<%# Bind("coursename") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:BoundField DataField="ttNo" HeaderText="#" SortExpression="ttNo" ReadOnly="True" />
                        <asp:TemplateField HeaderText="Course Date" SortExpression="startDate">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("startdate", "{0:M/d/yyyy}") %>'></asp:TextBox>
                                <asp:CalendarExtender ID="TextBox3_CalendarExtender" runat="server" Enabled="True"
                                    TargetControlID="TextBox3" Format="M/d/yyyy">
                                </asp:CalendarExtender>
                            </EditItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Label3" runat="server" Text='<%# Bind("startdate", "{0:M/d/yyyy}") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Expiry Date" SortExpression="endDate">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("enddate", "{0:M/d/yyy}") %>'></asp:TextBox>
                                <asp:CalendarExtender ID="TextBox1_CalendarExtender" runat="server" Enabled="True"
                                    TargetControlID="TextBox1" Format="M/d/yyyy">
                                </asp:CalendarExtender>
                            </EditItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="lblEndDate" runat="server" Text='<%# Bind("enddate", "{0:M/d/yyyy}") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                    </Columns>
                    <EmptyDataTemplate>No valid courses found.</EmptyDataTemplate>
                </asp:GridView>

UPDATE: I’ve been trying all your suggestions, but I get exceptions or nulls or empty strings. I’ve even re-created the problem in a simpler example and still can’t figure it out! I’ll keep trying though, and I appreciate any new suggestions.

Answer 1

Okay I finally figured out what is going on! I can only access the bound field through the row (e.g. e.Row.Cells[index].Text). So I used the bound field to get the ID of my item, then found the item in the database, got the date, compared it, and highlighted the row’s cells. Not the most efficient way, but it works.

Code from simple sample:

Grid View Front End

<asp:GridView ID="gdv" runat="server" AutoGenerateColumns="True" OnSelectedIndexChanged="gdv_SelectedIndexChanged">
        <Columns>
            <asp:CommandField ShowSelectButton="True" SelectText="Select" />
            <asp:BoundField DataField="id" HeaderText="#" ReadOnly="True" />
            <asp:TemplateField HeaderText="CategoryName" >
                <ItemTemplate>
                    <asp:Label ID="Label2" runat="server" Text='<%# Bind("name") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Description" >
                <ItemTemplate>
                    <asp:Label ID="Label3" runat="server" Text='<%# Bind("desc") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
    <asp:Label ID="lblSelected" runat="server" Text="No row selected"></asp:Label>

Code Behind Page

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack) {
        var qry = ctx.Categories
              .Select(c => new {
                  id = c.CategoryID,
                  name = c.CategoryName,
                  desc = c.Description,
              });
        gdv.DataSource = qry;
        gdv.DataBind();
    }
}

protected void gdv_SelectedIndexChanged(object sender, EventArgs e) {
    selectRow();
}

private void selectRow() {
    GridViewRow row = gdv.SelectedRow;
    String strId = row.Cells[1].Text; // Bound Field column
    lblSelected.Text = strId;
    // use ID to get object from database...
}