Eval() display custom value if null

<td>
    <asp:Label ID="TypeOfPaintingLabel" runat="server"
               Text='<%# Eval("TypeOfPainting") %>' />
</td>

Does anyone know how this works? I want to display "NA" if there is no value provided to TypeOfPainting.

Answers:

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Method 1

by creating a public method You can complete this task very easily like

public string testbind(object myvalue)
{
  if (myvalue == null)
  {
     return "NA value";
  }

  return myValue.ToString();
}

Label Code:

<asp:Label ID="TypeOfPaintingLabel" Text='<%# testbind(Eval("TypeOfPainting")) %>' runat="server"></asp:Label>

Or you may use

<%#(String.IsNullOrEmpty(Eval("TypeOfPainting").ToString()) ? "NA" : Eval("TypeOfPainting"))%>

You have to follow this type of scenarion.

Hope it works.

Method 2

Your control is runat="server" Why dont you control the value in codebehind?

If (string.IsNullOrEmpty(TypeofPaintingValue))
{
  TypeofPainting.Text="NA";
}

Method 3

Well you can try to do something like:

<%#(string.IsNullOrEmpty(Eval("TypeOfPainting").ToString()) ? "NA" : Eval("TypeOfPainting"))%>

Method 4

you can set this things from database side also

ISNULL(TypeOfPainting,'NA') AS TypeOfPainting

Method 5

I will suggest to do it in SQL only:

using ISNULL(expression, value_if_expression_is_null)
or

COALESCE(expression, expression2, expression3)

example :

SELECT
  Name, DOB,
  (CASE WHEN Address1 IS NULL THEN 'NA' ELSE Address1 END) AS Address1,
  (CASE WHEN Address2 IS NULL THEN 'NA' ELSE Address2 END) AS Address2,
  ...
FROM Users

or

SELECT 
  Name, DOB, Address1, 
  coalesce(Address2,'NA'), coalesce(City,'NA'), 
  coalesce(State,'NA'), coalesce(Zip,'NA')
FROM Users

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