Eval () can only be used in the context of a data management error. Why it happens? What can I do about it?
I am getting the following error: using asp.net and nHibernate.
Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.
I have this list
<asp:ListView ID="CurrentHourList" runat="server" ItemPlaceholderID="itemPlaceholder">
<LayoutTemplate>
<asp:PlaceHolder ID="itemPlaceholder" runat="server"></asp:PlaceHolder>
</LayoutTemplate>
<ItemTemplate>
<asp:ImageButton ID="DeleteDateButton" CausesValidation="false" runat="server" CommandName="Delete"
ImageUrl="img/delete.png" />
<span style="display: none">
<asp:Label ID="Id" runat="server" Text='<%# Eval("Id") %>'></asp:Label></span>
<asp:Label ID="Date" Text='<%# Eval("Date", "{0:dd MMM yyyy}") %>' runat="server"></asp:Label>
<asp:DropDownList ID="MedicalType" runat="server" SelectedValue='<%# Eval("MedicalType.Id") %>'>
<asp:ListItem Text="Paid" Value="1"></asp:ListItem>
<asp:ListItem Text="Unpaid" Value="2"></asp:ListItem>
<asp:ListItem Text="Special" Value="3"></asp:ListItem>
</asp:DropDownList>
Half-Day:<asp:CheckBox ID="HalfDay" runat="server" Checked='<%# Eval("IsHalfDay") %>' />
<br />
</ItemTemplate>
</asp:ListView>
and this is in my code for
private void BindData(string id)
{
MedLeaveHelper = new MedicalLeaveHelper();
DTO.MedLeaveDTO dto = MedLeaveHelper.GetMedicalRequest(id);
if (dto != null)
{
EnableForm();
this.RequestId.Text = dto.Id.ToString();
this.ddlEmployeeName.SelectedItem.Text = dto.User;
this.Note.Text = dto.Note;
this.CurrentHourList.DataSource = MedLeaveHelper.MakeMedicalDays(id);
this.CurrentHourList.DataBind();
}
MakeMedicalDays (id) just looks like this. MedicalDays is IList
internal IEnumerable MakeMedicalDays(string id)
{
int theId = 0;
if (int.TryParse(id, out theId))
{
MedicalRequest r = MedicalRequest.Get(theId);
return r.MedicalDays;
}
return null;
}
When I go to the DataBind () call, an error appears. I poked the phone, but nothing concrete jumped out at me. I tried to change the syntax to something like this
DataBinder.Eval(Container.DataItem,"id")
and the error goes away, but the data doesn't end up in my ListView.
As far as I understand, DataBinder.Eval uses reflection to determine my data type, but I'm not sure how to fix this issue. Any help you could provide would be great.
Thanks Jim
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Not sure if the problem is on your list. I tried a simple replay using the following data binding code - which worked fine with the ASPX you listed above:
this.CurrentHourList.DataSource = new[] { new { Id = 1, Date = DateTime.Now, MedicalType = new { Id = 1 }, IsHalfDay = false }, new { Id = 1, Date = DateTime.Now, MedicalType = new { Id = 1 }, IsHalfDay = false } };
this.CurrentHourList.DataBind();
Is it possible that the binding error is coming from another control (i.e. not inside the list?)
If you need to use declarative data binding to a control or property that doesn't support it, you can also look at creating your own custom expression builder.
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