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ImageField.AlternateText Property

Gets or sets the alternate text displayed for an image in the ImageField object.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)
public virtual string AlternateText { get; set; }

Property Value

Type: System.String
The alternate text for an image displayed in the ImageField object. The default is an empty string (""), which indicates that this property is not set.

Use the AlternateText property to specify the alternate text for the images displayed in an ImageField object. The alternate text is displayed when an image cannot be loaded or is unavailable. Browsers that support the ToolTips feature also display this text as a ToolTip.

NoteNote

When this property is set, all images displayed in an ImageField object share the same alternate text. As an alternative, you can bind the alternate text to a field in a data source by setting the DataAlternateTextField property instead of this property. This allows you to have different alternate text for each image displayed. If both the AlternateText and DataAlternateTextField properties are set, the DataAlternateTextField property takes precedence.

The value of this property, when set, can be saved automatically to a resource file by using a designer tool. For more information, see LocalizableAttribute and ASP.NET Globalization and Localization.

The following example demonstrates how to use the AlternateText property to specify the alternate text for all images displayed in an ImageField object.


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ImageField Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>ImageField Example</h3>

      <asp:gridview id="EmployeesGrid"
        autogeneratecolumns="false"
        datasourceid="EmployeeSource"  
        runat="server">

        <columns>

          <asp:imagefield dataimageurlfield="PhotoPath"
            alternatetext="Employee Photo"
            nulldisplaytext="No image on file."
            headertext="Photo"  
            readonly="true"/>
          <asp:boundfield datafield="FirstName"
            headertext="First Name"/>
          <asp:boundfield datafield="LastName"
            headertext="Last Name"/>

        </columns>

      </asp:gridview>

      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the Web.config file.                            -->
      <asp:sqldatasource id="EmployeeSource"
        selectcommand="Select [EmployeeID], [LastName], [FirstName], [PhotoPath] From [Employees]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>

    </form>
  </body>
</html>

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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