Databind Function to Controls Visible Property Does Not Work

Question

I'm using databinding to set the visible property on a control as such:

Control on Page:

<asp:LinkButton ID="ApproveTimeLink" runat="server"  Visible="<%# CanApprove() %>"> Approve Time</asp:LinkButton>

Code on CodeBehind:

Protected bool CanApprove()
{
  return false;
}

As you can see the control should not show, yet still does. I'm not getting any errors, and I'm baffled as to why this does not work.

Thanks for the help.

Answer 1

Sometimes you cannot set control properties with <%# %> and you have to resort to using OnItemDataBound(...) to get a reference to the control and set its Visible property there. Another thing that sometimes can be an issue is nested quotes, but in your sample code I don't see that as a problem. If your real code includes nested quotes, like Visible="<%# CanApprove(Eval("ID"))%>" then that may be your real issue. You can get around this by using single quotes and alternating with double quotes.

Answer 2

all you have to this is the following

protected void Page_Load(object sender, EventArgs e)
{
    this.DataBind();
}
public bool CanApprove()
{
    return false;
}

then you can use this method on the asp-control as you mentioned before!

but be we aware! Every property of the page has to be not null, otherwise the databind will fail with an exception!

Answer 3

This worked great for me too... thanks!!

<asp:Label runat="server" ID="lblLocaton" Text='<%# String.Format("{0}, {1}", Eval("City"), Eval("Region.Code")) %>'  Visible="<%# ShowLocation() %>" />

AND

MfnPresenter.Website.Presenters.IInstituitonListView.ShowLocation


    Get

    End Get
    Set(ByVal value As Boolean)

        'Used by visibility binding expression on lblLocation control inside dlFinancialInsitution

    End Set
End Property