I am having trouble accessing the data field. I receive the error: Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.
I can get the value but using <%# getOpenJobs((string)Eval("ParentPart")) %> but I need to use it in the if to display a certian picture if it passes the condition. Is there a better way to do this or am i just missing something simple?
<telerik:GridTemplateColumn UniqueName="hasOpenJobs" HeaderText="">
<ItemTemplate>
<% if (getOpenJobs((string)Eval("ParentPart")) > 1)
{ %>
<img src="../images/job-icon.gif" alt="Open Jobs" />
<%} %>
</ItemTemplate>
</telerik:GridTemplateColumn>
In these cases, I usually create a method in the code-behind to send back the final generated HTML. E.g.
<ItemTemplate>
<%# GetJobImageHtml((string)Eval("ParentPart")) %>
</ItemTemplate>
Then do whatever logic you need in the GetJobImageHtml() method and return a HTML string.
Related
From an aspx page, I am trying to display a user control for each item in a collection, but the C# seems to be ignored when tryign to set the UserControl parameter:
<%foreach (Fetus item in this.pregnancy.Fetus) {%>
//this returns a GUID:
"<%= item.Id.ToString() %>"
//this does not work, returns the characters between "" like < %= item.Id.ToString()%>:
<uc1:AntepartumCTGChart runat="server" ID="AntepartumCTGChart" FetusId="<%= item.Id.ToString()%>" />
<% } %>
I would expect this to work, what's wrong?
You have to use a data binding expression
<uc1:AntepartumCTGChart runat="server" ID="AntepartumCTGChart" FetusId='<%# item.Id.ToString()%>' />
But you have to call DataBind() in code behind for that to work.
You can also use a Repeater
<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<uc1:AntepartumCTGChart runat="server" ID="AntepartumCTGChart" FetusId='<%# Eval("id").ToString()%>' />
</ItemTemplate>
</asp:Repeater>
And then bind data to it in code behind
Repeater1.DataSource = pregnancy.Fetus;
Repeater1.DataBind();
I have the following repeater code:
<asp:Repeater ID="repMain" runat="server" OnItemCommand="repMain_ItemCommand" EnableViewState="false">
<ItemTemplate>
<dmg:testcontrol runat="server" MyData=<%#Container.DataItem %>>
</dmg:testcontrol>
</ItemTemplate>
</asp:Repeater>
The testcontrol usercontrol looks like:
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="TestControl.ascx.cs" Inherits="TestRepeater.TestControl" %>
<asp:Literal runat="server" ID="litMain" Text="<%#MyData.MyValue %>"></asp:Literal>
<asp:DropDownList runat="server" ID="dropdownMain"></asp:DropDownList>
<asp:Button runat="server" ID="btnMain" Text="Click Me" CommandName="Update" CommandArgument="<%#dropdownMain.SelectedValue%>"/>
Is it possible for me to send through the dropdownMain.SelectedValue as the CommandArgument?
Just now it is an empty string.
Thanks
Duncan
PS This is related to ASP.NET Repeater not binding after ItemCommand but I thought the two sufficiently different to keep apart.
A bit old question but I just my self found the answer to this one.
CommandArgument="<%#dropdownMain.SelectedValue%>"
Needs to look like this instead with single quotes! All inline codes within a asp.net controls have to be done this way instead.
CommandArgument='<%#dropdownMain.SelectedValue%>'
Why not get the selected value, and use it inside the Command function ?
(why to try to send it as argument, from the moment you can get it inside the command called function and its the same)
1) On aspx page we define GridView control named gvwPolls, and inside its template we define a user control named pollBox1
<asp:GridView ID="GridView1" DataSourceID="objPolls" ...>
<Columns>
<asp:TemplateField>
<ItemTemplate>
Question is : <%# Eval("QuestionText") %> <br />
<mb:PollBox ID="PollBox1" runat="server" PollID='<%# Eval("ID") %>' />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<asp:ObjectDataSource ID="objPolls" ...></asp:ObjectDataSource>
a) I assume that inside gvwPolls’s template, the gvwPollBox1.DataBind is called before PollID='<%# Eval("ID") %>' and <%# Eval("QuestionText") %> expressions get evaluated?!
b) Can someone offer some explanation how or why is gvwPollBox1.DataBind called before PollID='<%# Eval("ID") %>' and <%# Eval("QuestionText") %> expressions get evaluated?
2) Continuing with the above example:
-- pollBox1 user control defines a Repeater control named rptOptions:
<asp:Repeater runat="server" ID="rptOptions">
<ItemTemplate>
<%# Eval("pollBoxTitle") %>
</ItemTemplate>
</asp:Repeater>
-- In pollBox1’s code-behind file we bind rptOptions to a data source inside DoBinding() method.
-- We also override pollBox1’s DataBind() method:
public override void DataBind()
{
base.DataBind();
DoBinding();
}
a) I assume that due to overriding pollBox1.DataBind(), the data binding expression <%# Eval("pollBoxTitle") %> ( defined inside rptOptions’s template ) will get evaluated prior to a call to DoBinding method? If so, won’t then <%# Eval("pollBoxTitle") %> get evaluated before rptOptions is actually bound to a data source?
b) If that is the case, how then is rptOptions able to extract value ( from data source’s pollBoxtitle property) from a data source, if at the time the <%# Eval("pollBoxTitle") %>
expression got evaluated, rptOptions wasn’t yet bound to any data source?
thanx
I can't explain why the page life cycle is the way that is, probably has something to do with rendering childs before the parent object. When exactly do you call .DataBind() in the PollBox control? Try to move it into an event that is later in the life cycle, like PreRender.
There is also another way to ensure it is working the way you want to:
Subscribe to the RowDataBound Event, use .FindControl("YourPollBoxID") to get the instance of the control current bound row, set the properties and perform a manuall .DataBind();
Is something like this possible?
<asp:FormView ID="myFormView" runat="server">
<ItemTemplate>
<p><%# XPath("Root/Path/Item[#id=<%=this.m_myId%>]/HelloWorld")%></p>
</ItemTemplate>
</asp:FormView>
m_myId is a member variable on the page. I can't seem to get it to work without a parsing error.
You can't have nested asp tags. Try something like this:
<%# XPath("Root/Path/Item[#id= " + this.m_myId + "]/HelloWorld") %>
I am trying to use Eval inside a IF Statement and Repeater.
I want to do something like this:
<asp:Repeater runat="server" ID="rpRepeater">
<ItemTemplate>
<% if ((bool)Eval("A_Boolean"))
{ %>
blah...
<% } %>
</ItemTemplate>
</asp:Repeater>
This code gives me the following error:
Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.
Eval can be only used inside "binding" tag.
<%# Eval("A_Boolean") %>
http://support.microsoft.com/kb/307860#1a
It is possible to simulate if statements like this (code goes within ItemTemplate).
<asp:Panel runat="server" Visible='<%# Eval("A_Boolean") %>'>
blah...
</asp:Panel>