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Can't set Visible attribute in ASP.NET panels

I am having problems with the visible attribute of an ASP.NET control Panel

. I have a page that calls a database table and returns the results in a datagrid.

Requirements

If some of the return values null

, I need to hide the image that is next to it.

I am using Panel

to determine whether to hide or show an image, but I am having trouble with the assertion:

visible='<%# Eval("addr1") <> DBNull.Value %>'

I tried it too:

visible='<%# Eval("addr1") <> DBNull.Value %>'
visible='<%# IIf(Eval("addr1") Is DbNull.Value, "False","True") %>'

Code below:

<asp:TemplateField >
     <ItemTemplate>
          <%# Eval("Name")%>
               <p>
                   <asp:Panel runat="server" ID="Panel1" 
                        visible='<%# Eval("addr1") <> DBNull.Value %>'>
               <asp:Image Id="imgHouse" runat="server" 
                        AlternateText="Address" SkinId="imgHouse"/>                
               </asp:Panel>
           <%# Eval("addr1") %><p>                                             
</ItemTemplate>
</asp:TemplateField>

What am I doing wrong?

Edit

If i use visible='<%# IIf(Eval("addr1") Is DbNull.Value, "False","True") %>'

I am getting the following error:

Compiler Error Message: CS1026: ) expected
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4 answers


try:



<%# String.IsNullOrEmpty(DataBinder.Eval(Container.DataItem,"addr1").ToString()) #>

+1


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try comparing the eval result with a space, not null.



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This will probably be easier to accomplish with server side code.

Handle the RowDataBound event on your grid (assuming you are using a gridview, for the DataGrid it is ItemDataBound) and then do the following:

public void grid1_RowDataBound(object sender, GridViewRowDataBoundEventArgs e)
{
   if(e.Row.RowType == RowType.DataRow)
   {
        object itemFromDb = e.Row.DataItem;  //you'll need to cast this to your type
        Panel p = (Panel)e.Row.FindControl("myPanel");
        if(itemFromDb.SomeItem == null)
           p.Visible = false;
   }
}

This is from the top of my head, I might have a syntax error or 2. But you have an idea.

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Hmmm ...

visible = '<% # IIf (Eval ("addr1") Is DbNull.Value, "False", "True")%>'

Must work. What error are you getting?

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