XPathBinder.Eval Method (Object, String, String)


Evaluates XPath data-binding expressions at run time and formats the result as text to be displayed in the requesting browser.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

public static string Eval(
	object container,
	string xPath,
	string format


Type: System.Object

The IXPathNavigable object reference that the expression is evaluated against. This must be a valid object identifier in the page's specified language.

Type: System.String

The XPath query from the container to the property value to be placed in the bound control property.

Type: System.String

A .NET Framework format string, similar to those used by String.Format, that converts the IXPathNavigable object (which results from the evaluation of the data-binding expression) to a String that can be displayed by the requesting browser.

Return Value

Type: System.String

A String that results from the evaluation of the data-binding expression and conversion to a string type.

Exception Condition

The container or xpath parameter is null.


The object specified by container is not an IXPathNavigable.

To learn more about format strings in the .NET Framework, see Formatting Types in the .NET Framework.

You can use the Eval(Object, String) method declaratively if you want to simplify the casting of an XML node to a text string to be displayed in a browser. To do so, you must place the <%# and %> tags, which are also used in standard ASP.NET data binding, around the data-binding expression.

For any of the list ASP.NET server controls, such as DataList, DataGrid, or Repeater, the container parameter should be Container.DataItem. If you are binding against the page, the container parameter should be Page.

.NET Framework
Available since 2.0
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