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CreateParams.Style Property

Gets or sets a bitwise combination of window style values.

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

public int Style { get; set; }

Property Value

Type: System.Int32
A bitwise combination of the window style values.

The Style property controls the appearance of the control and its initial state.

For more information about creating control parameters, see the CreateWindow and CreateWindowEx functions and the CREATESTRUCT structure documentation in the Windows Platform SDK reference located in the MSDN Library.

NoteNote:

The constants used to set the Style, ExStyle, and ClassStyle properties are defined in the Winuser.h header file. This file is installed by the Platform SDK or Visual Studio .NET.

The following code example creates a Button derived class named MyIconButton and provides the implementation needed for the button to display an icon rather than an image. The CreateParams property is extended and a value added to the Style property that causes the button to display an Icon rather than an Image.

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.IO;
using System.Security.Permissions;

[SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
public class MyIconButton : Button
{

    private Icon icon;

    public MyIconButton()
    {
        // Set the button's FlatStyle property.
        FlatStyle = FlatStyle.System;
    }

    public MyIconButton(Icon ButtonIcon)
        : this()
    {
        // Assign the icon to the private field.    
        this.icon = ButtonIcon;


        // Size the button to 4 pixels larger than the icon. 
        this.Height = icon.Height + 4;
        this.Width = icon.Width + 4;
    }

    protected override CreateParams CreateParams
    {
        get
        {
            new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Demand();

            // Extend the CreateParams property of the Button class.
            CreateParams cp = base.CreateParams;
            // Update the button Style.
            cp.Style |= 0x00000040; // BS_ICON value 

            return cp;
        }
    }

    public Icon Icon
    {
        get
        {
            return icon;
        }

        set
        {
            icon = value;
            UpdateIcon();
            // Size the button to 4 pixels larger than the icon. 
            this.Height = icon.Height + 4;
            this.Width = icon.Width + 4;
        }
    }

    [SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
    protected override void OnHandleCreated(EventArgs e)
    {
        base.OnHandleCreated(e);

        // Update the icon on the button if there is currently an icon assigned to the icon field. 
        if (icon != null)
        {
            UpdateIcon();
        }
    }

    private void UpdateIcon()
    {
        IntPtr iconHandle = IntPtr.Zero;

        // Get the icon's handle. 
        if (icon != null)
        {
            iconHandle = icon.Handle;
        }

        // Send Windows the message to update the button. 
        SendMessage(Handle, 0x00F7 /*BM_SETIMAGE value*/, 1 /*IMAGE_ICON value*/, (int)iconHandle);
    }


    // Import the SendMessage method of the User32 DLL.   
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    public static extern IntPtr SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);

}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

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