CODEWITHSUNDEEP
asp.net
Ian Boyd
Ian Boyd

Reputation: 256591

How to pass multiple parameters to Eval()?

i have a bit of aspx code that uses Eval to generate a call to a javascript function:

ASP.NET (wrapped for readability):

<asp:LinkButton runat="server"
   OnClientClick='<%# Eval(
         "NodeGUID", 
         "return DoStuff(this, \"{0}\");") %>'
   Text="Do stuff" />

this generates javascript similar to:

Javascript (wrapped for readability):

return DoStuff(this,
      "3F2504E0-4F89-11D3-9A0C-0305E82C3301"
   );

Note: i've converted the generated &quot; entities references into quotes for readability.

i now need to add a 3nd parameter to the javascript function call, a caption:

Javascript (wrapped for readability)

return DoStuff(this,
      "3F2504E0-4F89-11D3-9A0C-0305E82C3301",
      "AllisonAngel.jpg"
   );

Note: i've converted the generated &quot; entities references into quotes for readability.

There already exists a function in the code-behind file that is used to return the caption for an item:

C# (code omitted for readability):

protected string GetItemText(MySomething item)
{
   ...
}

i know that the above function can be called from the aspx file using a syntax similar to:

ASP.NET (wrapped, code omitted, for readability):

<asp:LinkButton ... runat="server"
   Text="<%# GetItemText((MySomething)Container.DataItem) %>" 
   ... />

So now i want to use this function to include the 3rd parameter to the javascript function.

Starting from:

<asp:LinkButton runat="server"
   OnClientClick='<%# Eval(
         "NodeGUID",
         "return DoStuff(this, \"{0}\", \"Todo - Insert caption here\");") %>'
   Text="Do stuff" />

i need to change: "Todo - Insert caption here"

into a call to: <%# GetItemText((MySomething)Container.DataItem) %>

Blindly trying the obvious:

ASP.NET (wrapped for readability):

<asp:LinkButton runat="server"
   OnClientClick='<%# Eval(
         "NodeGUID", 
         GetItemText((MySomething)Container.DataItem),
         "return DoStuff(this, \"{0}\", \"{1}\");") %>'
   Text="Do stuff" />

But that complains, since Eval() only takes two parameters.

i tried the slightly less obivous:

ASP.NET (wrapped for readability)

<asp:LinkButton runat="server"
   OnClientClick='<%# Eval(
         "NodeGUID", 
         "return DoStuff(this, 
               \"{0}\", 
               \""+GetItemText((MySomething)Container.DataItem)+"\");") %>'
   Text="Do stuff" />

But that doesn't work either.

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Upvotes: 13

Views: 32717

Answers (6)

dnxit
dnxit

Reputation: 7350

you can try this

'<'asp:HyperLink ID="hp" runat="server" CommandArgument='<%# Eval("SysID", "{0}")%>' 
            NavigateUrl='<%#  String.Format("~/ReportViewer.aspx?RevID= {0} 
          & User={1}", Eval("ID"),  Eval("USER")) %>' Target="_blank"  %>'>
</asp:HyperLink>

http://afzal-gujrat.blogspot.com/2012/10/pass-more-evals-in-querystring-with.html

Upvotes: 0

Kevin Farrugia
Kevin Farrugia

Reputation: 7439

Continued from Scott Ivey's solution, you can also use this to include if statements in your Eval statement:

For example the below will output an anchor tag if the property Url exists, otherwise it will output a span.

<%# string.Format(Eval("Url") != null ? "<a href=\"{0}\">{1}</a>" : "<span>{1}</span>", Eval("Url"), Eval("Text")) %>">

Upvotes: 0

Scott Ivey
Scott Ivey

Reputation: 41558

The trick isn't to pass multiple items to an eval, but to pass multiple eval's to whatever you want to use to format the data. You could also have just done it this way - which would have kept the presentation in the aspx file like you wanted...

<asp:LinkButton 
   runat="server" 
   OnClientClick='<%# string.Format(
          "return DoStuff(this, \"{0}\", \"{1}\");", 
          Eval("NodeGUID"), 
          GetItemText((MySomething)Container.DataItem)) %>' 
   Text="Do stuff" />

Upvotes: 21

deadwalker82
deadwalker82

Reputation: 31

My Trick

Eval("FLName", Eval("FLFDID","{0}")+"/{0}")

Eval inside Eval

It Work for me !!

Upvotes: 3

Ian Boyd
Ian Boyd

Reputation: 256591

Robert C. Barth gave me the idea that solves the problem:

<asp:LinkButton runat="server"
      OnClientClick="<%# GetItemClientClick((MySomething)Container.DataItem) %>" 
      Text="Do stuff" />

and then the code-behind file contains:

protected string GetItemClientClick(MySomething item)
{
   ...

   String szOnClientClick =
      "return DeleteItem(this, "+
            Toolkit.QuotedStr(item.NodeGUID.ToString()) + ", "+
            Toolkit.QuotedStr(GetItemText(item))+");";

   return szOnClientClick;
}

i really would have preferred to keep presentation in the aspx, and business logic in the code-behind - but the real world often doesn't conform to that model.

Upvotes: 2

Robert C. Barth
Robert C. Barth

Reputation: 23315

If the LinkButton is not inside some other thing (like a grid), just set the OnClientClick attribute in the code-behind like normal, using string.Format.

If it IS in a grid (or repeater, or something of that nature), set it in the RowDataBound event using FindControl or e.Row.Cells[] and string.Format. If you use e.Row.Cells[], you can probably dump the LinkButton server control and just output a normal anchor tag.

Upvotes: 1

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