CODEWITHSUNDEEP
c#winformsflickerdoublebuffered
Ian Boyd
Ian Boyd

Reputation: 256581

How to double buffer .NET controls on a form?

How can I set the protected DoubleBuffered property of the controls on a form that are suffering from flicker?

Upvotes: 60

Views: 79118

Answers (14)

RG Orobia
RG Orobia

Reputation: 36

I created a static method that accepts a Control and sets the DoubleBuffered property to true to each and every children recursively.

public static void CascadingDoubleBuffer(Control c)
{
    var p = c.GetType().GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic);
    p?.SetValue(c, true, null);
    foreach (Control cc in c.Controls) CascadingDoubleBuffer(cc);
}

I created a custom calendar using DataGridView that refreshes everytime the user interacts with it, this method removes the migraine-inducing flicker.

Upvotes: 0

Gregor y
Gregor y

Reputation: 2050

FWIW

building on the work of those who've come before me:
Dummy's Solution, Ian Boyd's Solution, Amo's Solution

here is a version that sets double buffering via SetStyle in PowerShell using reflection

function Set-DoubleBuffered{
<#
.SYNOPSIS
Turns on double buffering for a [System.Windows.Forms.Control] object
.DESCRIPTION
Uses the Non-Public method 'SetStyle' on the control to set the three
style flags recomend for double buffering: 
   UserPaint
   AllPaintingInWmPaint
   DoubleBuffer
.INPUTS
[System.Windows.Forms.Control]
.OUTPUTS
None
.COMPONENT  
System.Windows.Forms.Control
.FUNCTIONALITY
Set Flag, DoubleBuffering, Graphics
.ROLE
WinForms Developer
.NOTES
Throws an exception when trying to double buffer a control on a terminal 
server session becuase doing so will cause lots of data to be sent across 
the line
.EXAMPLE
#A simple WinForm that uses double buffering to reduce flicker
Add-Type -AssemblyName System.Windows.Forms
[System.Windows.Forms.Application]::EnableVisualStyles()

$Pen = [System.Drawing.Pen]::new([System.Drawing.Color]::FromArgb(0xff000000),3)

$Form = New-Object System.Windows.Forms.Form
Set-DoubleBuffered $Form
$Form.Add_Paint({
   param(
      [object]$sender,
      [System.Windows.Forms.PaintEventArgs]$e
   )
   [System.Windows.Forms.Form]$f = $sender
   $g = $e.Graphics
   $g.SmoothingMode = 'AntiAlias'
   $g.DrawLine($Pen,0,0,$f.Width/2,$f.Height/2)
})
$Form.ShowDialog()

.LINK
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.setstyle?view=net-5.0
.LINK
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.controlstyles?view=net-5.0
#>
   param(
      [parameter(mandatory=$true,ValueFromPipeline=$true)]
      [ValidateScript({$_ -is [System.Windows.Forms.Control]})]
      #The WinForms control to set to double buffered
      $Control,
      
      [switch]
      #Override double buffering on a terminal server session(not recomended)
      $Force
   )
   begin{try{
      if([System.Windows.Forms.SystemInformation]::TerminalServerSession -and !$Force){
         throw 'Double buffering not set on terminal server session.'
      }
      
      $SetStyle = ([System.Windows.Forms.Control]).GetMethod('SetStyle',
         [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Instance
      )
      $UpdateStyles = ([System.Windows.Forms.Control]).GetMethod('UpdateStyles',
         [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Instance
      )
   }catch {$PSCmdlet.ThrowTerminatingError($PSItem)}
   }process{try{
      $SetStyle.Invoke($Control,@(
         ([System.Windows.Forms.ControlStyles]::UserPaint -bor
           [System.Windows.Forms.ControlStyles]::AllPaintingInWmPaint -bor
           [System.Windows.Forms.ControlStyles]::DoubleBuffer
         ),
         $true
      ))
      $UpdateStyles.Invoke($Control,@())
   }catch {$PSCmdlet.ThrowTerminatingError($PSItem)}}
}

Upvotes: -1

Ian Boyd
Ian Boyd

Reputation: 256581

Here's a more generic version of Dummy's solution.

We can use reflection to get at the protected DoubleBuffered property, and then it can be set to true.

Note: You should pay your developer taxes and not use double-buffering if the user is running in a terminal services session (e.g. Remote Desktop) This helper method will not turn on double buffering if the person is running in remote desktop.

public static void SetDoubleBuffered(System.Windows.Forms.Control c)
{
   //Taxes: Remote Desktop Connection and painting
   //http://blogs.msdn.com/oldnewthing/archive/2006/01/03/508694.aspx
   if (System.Windows.Forms.SystemInformation.TerminalServerSession)
      return;

   System.Reflection.PropertyInfo aProp = 
         typeof(System.Windows.Forms.Control).GetProperty(
               "DoubleBuffered", 
               System.Reflection.BindingFlags.NonPublic | 
               System.Reflection.BindingFlags.Instance);

   aProp.SetValue(c, true, null); 
}

Upvotes: 96

ljs
ljs

Reputation: 37807

I have found that simply setting the DoubleBuffered setting on the form automatically sets all the properties listed here.

Upvotes: 0

Flip70
Flip70

Reputation: 51

vb.net version of this fine solution....:

Protected Overrides ReadOnly Property CreateParams() As CreateParams
    Get
        Dim cp As CreateParams = MyBase.CreateParams
        cp.ExStyle = cp.ExStyle Or &H2000000
        Return cp
    End Get
End Property

Upvotes: 5

Hans Passant
Hans Passant

Reputation: 941218

Check this thread

Repeating the core of that answer, you can turn on the WS_EX_COMPOSITED style flag on the window to get both the form and all of its controls double-buffered. The style flag is available since XP. It doesn't make painting faster but the entire window is drawn in an off-screen buffer and blitted to the screen in one whack. Making it look instant to the user's eyes without visible painting artifacts. It is not entirely trouble-free, some visual styles renderers can glitch on it, particularly TabControl when its has too many tabs. YMMV.

Paste this code into your form class:

protected override CreateParams CreateParams {
    get {
        var cp = base.CreateParams;
        cp.ExStyle |= 0x02000000;    // Turn on WS_EX_COMPOSITED
        return cp;
    } 
}

The big difference between this technique and Winform's double-buffering support is that Winform's version only works on one control at at time. You will still see each individual control paint itself. Which can look like a flicker effect as well, particularly if the unpainted control rectangle contrasts badly with the window's background.

Upvotes: 73

dnennis
dnennis

Reputation: 140

This caused me a lot of grief for two days with a third party control until I tracked it down.

protected override CreateParams CreateParams
{
    get
    {
        CreateParams cp = base.CreateParams;
        cp.ExStyle |= 0x02000000;
        return cp;
    }
}

I recently had a lot of holes (droppings) when re-sizing / redrawing a control containing several other controls.

I tried WS_EX_COMPOSITED and WM_SETREDRAW but nothing worked until I used this:

private void myPanel_SizeChanged(object sender, EventArgs e)
{
     Application.DoEvents();
}

Just wanted to pass it on.

Upvotes: 4

Dmitry Romanov
Dmitry Romanov

Reputation: 14090

Extension method to turn double buffering on or off for controls

public static class ControlExtentions
{
    /// <summary>
    /// Turn on or off control double buffering (Dirty hack!)
    /// </summary>
    /// <param name="control">Control to operate</param>
    /// <param name="setting">true to turn on double buffering</param>
    public static void MakeDoubleBuffered(this Control control, bool setting)
    {
        Type controlType = control.GetType();
        PropertyInfo pi = controlType.GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic);
        pi.SetValue(control, setting, null);
    }
}

Usage (for example how to make DataGridView DoubleBuffered):

DataGridView _grid = new DataGridView();
//  ...
_grid.MakeDoubleBuffered(true);

Upvotes: 5

dummy
dummy

Reputation: 4284

System.Reflection.PropertyInfo aProp = typeof(System.Windows.Forms.Control)
    .GetProperty("DoubleBuffered", System.Reflection.BindingFlags.NonPublic |
    System.Reflection.BindingFlags.Instance);
aProp.SetValue(ListView1, true, null);

Ian has some more information about using this on a terminal server.

Upvotes: 19

Chris S
Chris S

Reputation: 65426

nobugz gets the credit for the method in his link, I'm just reposting. Add this override to the Form:

protected override CreateParams CreateParams
{
    get
    {
        CreateParams cp = base.CreateParams;
        cp.ExStyle |= 0x02000000;
        return cp;
    }
}

This worked best for me, on Windows 7 I was getting large black blocks appearing when I resize a control heavy form. The control now bounce instead! But it's better.

Upvotes: 5

Joel Coehoorn
Joel Coehoorn

Reputation: 415600

Before you try double buffering, see if SuspendLayout()/ResumeLayout() solve your problem.

Upvotes: 4

Jeff Hubbard
Jeff Hubbard

Reputation: 9892

One way is to extend the specific control you want to double buffer and set the DoubleBuffered property inside the control's ctor.

For instance:

class Foo : Panel
{
    public Foo() { DoubleBuffered = true; }
}

Upvotes: 10

MagicKat
MagicKat

Reputation: 9821

You can also inherit the controls into your own classes, and set the property in there. This method is also nice if you tend to be doing a lot of set up that is the same on all of the controls.

Upvotes: 1

Arno
Arno

Reputation: 2239

public void EnableDoubleBuffering()
{
   this.SetStyle(ControlStyles.DoubleBuffer | 
      ControlStyles.UserPaint | 
      ControlStyles.AllPaintingInWmPaint,
      true);
   this.UpdateStyles();
}

Upvotes: 13

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