FileDialog.HookProc Method (System.Windows.Forms)

HookProc Method

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Microsoft Visual Studio 2010/.NET Framework 4

Other versions are also available for the following:

.NET Framework Class Library

FileDialog..::.HookProc Method

This member overrides CommonDialog..::.HookProc(IntPtr, Int32, IntPtr, IntPtr), and more complete documentation might be available in that topic.

Defines the common dialog box hook procedure that is overridden to add specific functionality to the file dialog box.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

Syntax

Visual Basic

<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
Protected Overrides Function HookProc ( _
    hWnd As IntPtr, _
    msg As Integer, _
    wparam As IntPtr, _
    lparam As IntPtr _
) As IntPtr

[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
protected override IntPtr HookProc(
    IntPtr hWnd,
    int msg,
    IntPtr wparam,
    IntPtr lparam
)

Visual C++

[SecurityPermissionAttribute(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::UnmanagedCode)]
protected:
virtual IntPtr HookProc(
    IntPtr hWnd, 
    int msg, 
    IntPtr wparam, 
    IntPtr lparam
) override

[<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)>]
abstract HookProc : 
        hWnd:IntPtr * 
        msg:int * 
        wparam:IntPtr * 
        lparam:IntPtr -> IntPtr 
[<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)>]
override HookProc : 
        hWnd:IntPtr * 
        msg:int * 
        wparam:IntPtr * 
        lparam:IntPtr -> IntPtr

Parameters

hWnd: Type: System..::.IntPtr
The handle to the dialog box window.

msg: Type: System..::.Int32
The message received by the dialog box.

wparam: Type: System..::.IntPtr
Additional information about the message.

lparam: Type: System..::.IntPtr
Additional information about the message.

Return Value

Type: System..::.IntPtr
Returns zero if the default dialog box procedure processes the message; returns a nonzero value if the default dialog box procedure ignores the message.

Remarks

A hook procedure allows the user to connect or insert other routines into a routine or application for the purpose of debugging or enhancing functionality.

By default, the hook procedure centers the dialog box on the screen in response to a WM_INITDIALOG message.

Notes to Inheritors

When overriding HookProc in a derived class, be sure to call the base class's HookProc method.

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Reference

FileDialog Class

System.Windows.Forms Namespace