Eval Check String Null or Empty

Question

<asp:TemplateField HeaderText="Customer Account Name">
     <ItemTemplate>
         <asp:Label ID="lblRecieverClientAccountName" runat="server" 
              Text='<%#Eval("RecieverClientAccountName").ToString()) ? 
               String.Empty : 'Invalid Account number'
               ,"RecieverClientAccountName" %>'></asp:Label>
     </ItemTemplate>
</asp:TemplateField>

I need to check string is empty and show a custom message .It gives me an error "The server tag is not well formed."

the problem is .ToString(). You should check it before .ToString() function. — शेखर, Nov 18 '15 at 09:29
That is not legal C#, what kind of **character** is this? `'Invalid Account number'`? — Lasse V. Karlsen, Sep 07 '19 at 20:04
Possible duplicate of [The server tag is not well formed error](https://stackoverflow.com/questions/15278616/the-server-tag-is-not-well-formed-error) — Lasse V. Karlsen, Sep 07 '19 at 20:05

score 0 · Answer 1 · edited May 23 '17 at 11:59

The problem is .ToString(). You should check it before .ToString() function

Try as below

<asp:Label ID="lblRecieverClientAccountName" runat="server" 
          Text='<%#Eval("RecieverClientAccountName")) ? 
           String.Empty : 'Invalid Account number'
           ,"RecieverClientAccountName" %>'></asp:Label>

Or check it for null values.

<asp:Label ID="lblRecieverClientAccountName" runat="server" 
          Text='<%#Eval("RecieverClientAccountName"))==
          null : 'Invalid Account number'
           ,"RecieverClientAccountName" %>'></asp:Label>

I have not tested it so far.

Edit 1

Try this

<%#(String.IsNullOrEmpty(Eval("RecieverClientAccountName").ToString()) ?...

Similar Question on SO Using '<%# Eval("item") %>'; Handling Null Value and showing 0 against

score 0 · Answer 2 · edited Jan 07 '16 at 08:24

0

<asp:TemplateField HeaderText="Customer Account Name">
 <ItemTemplate>
     <asp:Label ID="lblRecieverClientAccountName" runat="server" 
          Text='<%#Eval("RecieverClientAccountName") ? 
           String.Empty : 'Invalid Account number, ' +
           Eval("RecieverClientAccountName") %>'></asp:Label>
 </ItemTemplate>

edited Jan 07 '16 at 08:24

Kushal Vora

342
2
16

answered Nov 18 '15 at 09:31

Kaushik Maheta

1,741
1
18
27

score 0 · Answer 3 · answered Nov 18 '15 at 10:15

0

Try this..

<asp:Label ID="lblRecieverClientAccountName" runat="server" 
           Text='<%#Eval("RecieverClientAccountName")) ?
           "" : 'Invalid Account number'
           ,"RecieverClientAccountName" %>'></asp:Label>

answered Nov 18 '15 at 10:15

Rajeesh Menoth

1,704
3
17
33

score 0 · Answer 4 · answered Aug 27 '18 at 07:03

You had error: "The server tag is not well formed." because of:

'Invalid Account number'

you have to change it to:

"Invalid Account number"

You can use Eval function like this:

Eval("RecieverClientAccountName") == null ? "" : Eval("RecieverClientAccountName").ToString()

or

Eval("RecieverClientAccountName") == DBNull.Value ? "" : Eval("RecieverClientAccountName").ToString()

score -1 · Answer 5 · answered Feb 13 '18 at 14:46

-1

Check Eval values Null or Not Null

<%# string.IsNullOrEmpty(Eval("RecieverClientAccountName").ToString())?  "Null" : "Values" %>

answered Feb 13 '18 at 14:46

Jangli Coder

89
1
1
10

Exception happens at .ToString() if Eval("ReceiverClientAccountName") is null. – Linh Dao Aug 27 '18 at 06:46
string.IsNullOrEmpty(Eval("RecieverClientAccountName").ToString()) here i am checking the values is null or not null and it is not posible to happen error – Jangli Coder Sep 19 '18 at 12:49

Eval Check String Null or Empty

5 Answers5

Edit 1