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Publisher12.4 Methods Reference
| DataBind |
Page.DataBind( ) |
expressions in the page. It also calls DataBind on all child
controls.
Parameters
None.
Example
The following code example uses a data-binding expression to set the
ForeColor attribute of a label control tag to the
value of local variable named color. When the DataBind method is
called in Page_Load, the value of the Color variable is assigned to
the ForeColor attribute (which is effectively the
same as setting the ForeColor property in code):
<%@ Page Language="vb" %>
<html>
<head>
<title></title>
<script runat="server">
Dim Color As System.Drawing.Color = System.Drawing.Color.Red
Sub Page_Load( )
Message.Text = "ForeColor is: " & Color.Name
DataBind( )
End Sub
</script>
</head>
<body>
<asp:label id="Message" ForeColor="<%# Color %>" runat="server"/>
</body>
</html>
Notes
If you want to perform data binding on a specific control on the
page, such as a DataGrid or DataList control, it may be more
efficient to call DataBind on that control rather than on the page,
since calling it on the control will avoid any overhead in calling
DataBind on controls for which data binding is not needed.
| FindControl |
Control = Page.FinderControl(String) |
whose name corresponds to a search string. The FindControl method is
a member of the base Control class.
Parameters
- Control
An instance of the Control class that represents
the control that is found using the FindControl method. This control
must be cast to the correct control type to access members that are
specific to the control type.- String
A string containing the programmatic identifier of the control. This
value is the same as the ID attribute of a
declarative control or, in the case of controls created at runtime,
is the same as the object name defined for the control.
Example
The example finds a control using its ID and changes its background
color:
Sub Page_Load( )
Dim TheControl As Control = FindControl("Message")
If Not TheControl Is Nothing Then
Dim TheLabel As Label = CType(TheControl, Label)
TheLabel.Text = "Found the label named Message!"
TheLabel.BackColor = System.Drawing.Color.Blue
End If
End Sub
Notes
The FindControl method, which is inherited from the
Control class (from which the
Page class is derived), is useful when dealing
with nested controls or user controls that need to manipulate a
control in their parent page. For example, code in a user control
could call FindControl on the page containing the user control to
locate and manipulate a control contained within the page (but
outside the user control).
| HasControls |
Boolean = Page.HasControls( ) |
value that indicates whether the page contains child controls.
Parameter
- Boolean
A Boolean value that indicates whether the page contains child
controls.
Example
The code example displays a message indicating whether the page has
controls in its Controls collection, based on the value returned by
HasControls:
Sub Page_Load( )
If Page.HasControls = True Then
Message.Text = "The page contains controls."
Else
Message.Text = "The page does not contain controls."
End If
End Sub
| LoadControl |
ObjControl = Page.LoadControl(StrPath) |
of the user control defined in the strPath
user control file. This allows dynamic loading of user controls
instead of using the @ Register
directive.
Parameters
- objControl
An object of type Control that represents the user control specified
in the given path.- strPath
The virtual path to a user control file.
Example
The example uses the LoadControl to load a user control at runtime
and adds it to the page's Controls collection:
Sub Page_Load( )
Dim Hello As UserControl = LoadControl("hello.ascx")
Page.Controls.Add(Hello)
End Sub
The user control hello.ascx is as follows:
<h1>Hello, World!</h1>
| MapPath |
String = Page.MapPath(virtualPath) |
that corresponds to a given virtual path.
Parameters
- String
A String containing the physical path that corresponds to
virtualPath.- virtualPath
A string containing an absolute or relative virtual path.
Example
The example maps the virtual path of the named page to its physical
path:
Sub Page_Load( )
Message.Text = MapPath("MapPath.aspx")
End Sub
Notes
The Page.MapPath method duplicates the functionality of the
Server.MapPath method.
| ResolveUrl |
String = Path.ResolveUrl(strRelativeUrl) |
absolute URL corresponding to a relative URL.
Parameters
- String
A string containing the absolute URL.- strRelativeUrl
A relative URL.
Example
The example maps the current relative URL to an absolute URL:
Sub Page_Load( )
Message.Text = Page.ResolveUrl("ResolveUrl.aspx")
End Sub
| Validate |
Page.Validate( ) |
validation logic for each validator control on the page. When this
method is invoked, it iterates the Page object's
ValidatorCollection collection and executes the validation logic
associated with each validator control.
Example
See the example for the IsValid property.
Notes
The Validate method is called automatically when the user clicks any
HTML or ASP button control whose CausesValidation property is
True.
