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C# Windows Form Application Transparent button

I'm new to C#. I'd like to create an invisible button, but they are click-able in C# windows form application. Is there a way? I tried BackColor to Transparent, but that does not change the fact that it is transparent

Its simple try this.
Click the button that you want to make transparent.
Select FlatStyle from Properties and set it to popup
Now change the BackColor property to Transparent.
This will make the button transparent.
However if you want to make it transparent over a PictureBox this method wont work..
It works only on normal backgrounds and background images.
Hope it works....

buttonLink.FlatStyle = FlatStyle.Flat;
buttonLink.BackColor = Color.Transparent;
buttonLink.FlatAppearance.MouseDownBackColor = Color.Transparent;
buttonLink.FlatAppearance.MouseOverBackColor = Color.Transparent;

The answers given just make the background color of the control you want to make transparent the same as the background color of its parent. It's not true transparency and windows forms doesn't support true transparency.
Windows Forms controls do not support true transparency. The background of a
transparent Windows Forms control is painted by its parent.
https://learn.microsoft.com/en-us/dotnet/desktop/winforms/controls/how-to-give-your-control-a-transparent-background?view=netframeworkdesktop-4.8&redirectedfrom=MSDN

Reference:
Original article and code can be found at:
Displaying a ToolTip when the Mouse Hovers Over a Disabled Control
# CodeProject by tetsushmz
Code:
public class TransparentSheet : ContainerControl
{
public TransparentSheet()
{
// Disable painting the background.
this.SetStyle(ControlStyles.Opaque, true);
this.UpdateStyles();
// Make sure to set the AutoScaleMode property to None
// so that the location and size property don't automatically change
// when placed in a form that has different font than this.
this.AutoScaleMode = AutoScaleMode.None;
// Tab stop on a transparent sheet makes no sense.
this.TabStop = false;
}
private const short WS_EX_TRANSPARENT = 0x20;
protected override CreateParams CreateParams
{
[SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
get
{
CreateParams l_cp;
l_cp = base.CreateParams;
l_cp.ExStyle = (l_cp.ExStyle | WS_EX_TRANSPARENT);
return l_cp;
}
}
}
Explanation:
What you need to do is use the given control as an overlay on your disabled TextBox (that you mentioned in one of your comments). Sibscribe to the overlay control's Click event and you have yourself a click on a disabled control.
I strongly recommend against this approach and feel it is kind of a hack. You really should look for an alternative approach instead of having to use a disabled control with an overlay control on top of it.
Maybe a different UI or atleast wrap it up in a UserControl to isolate this messy logic.

Setting the background property of the button to transparent will still leave a border. If you want a completely transparent button, do one of 2 things:
Create a transparent panel and assign a method to the Click event
or preferably
Create a custom UserControl that is filled with only BackColor (set to transparent) and assign method to Click event.
public class Invisible_Button : UserControl
{
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
this.Cursor = Cursors.Hand;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.FillRectangle(new SolidBrush(this.BackColor), 0, 0, this.Width, this.Height);
}
}

Did you try button.Visible = false?
If all you want is to hide it, this will do the job.

How can I add transparency to a c# form while keeping controls visible?

UPDATE: I took a break from messing with the transparency stuff for a few days. I started messing with it again tonight. I got a new result using Hans Passant's solution:
http://img3.imageshack.us/img3/4265/icontransp.jpg
Passant's solution does solve the issue of the transparent background gradient. However, I'm still running into the problem with the transparent colors in my icon blending with the form's BackColor. You can see the fuchsia around various parts of the icon in the above image.
ORIGINAL CONTENT:
I've been going at this for several hours now, and I haven't had much luck. I've messed with Control.Region, Form.TransparencyKey, Form.Opacity, and a couple other random things with some funky effects.
Lately I've been trying to customize my desktop and decided to mess with Application Docks. After seeing what the Mac dock and a few third-party Windows implementations had to offer, I decided I wanted to build my own.
Eventually I want to move on to using the Win32 API. For now I just want to get something working using as much C# and .Net framework capabilities as possible.
There are a few things I want to be able to do in this application:
Display a form/menu with a gradient background.
Allow the form/menu to have transparency while keeping icons opaque.
Display icons that contain transparent backgrounds.
The Menu and Icons should be able to receive mouse-related events (hover, leave, click, dragover, dragdrop, and a few others).
This is the effect I'm shooting for:
http://img207.imageshack.us/img207/5716/desired.jpg
This image shows the visual effects I'm trying to achieve. This was a skin I made for a program called Rainmeter. The image shows Notepad++ behind the skin with a few of the skin's files open in the editor. The menu is transparent, but the icons remain opaque.
My Approach:
Using a Form to act as the menu seemed like a logical first choice to me. I have a basic understanding of events. I'm not quite sure how to create my own click events, so a form would make working with events a tad easier. I considered a few options for the icons. I decided I'd use PictureBoxes for the icons, since they can hold images and receive events.
Once I finished the code for all the structural logic of my menu, I started playing around with it to try to get the visual effect I wanted. Form.Opacity affected the transparency of everything on the form. Since I want the icons to be fully opaque, I left this property alone. I tried setting the BackColor to Color.Transparent, but that gives an error. I played around with a few combinations...
http://img204.imageshack.us/img204/757/effectsi.jpg
I drew the gradient with a Drawing2D.LinearGradientBrush into a Bitmap. This Bitmap was then placed as the Form.BackgroundImage or as a PictureBox.Image. If used, the PictureBox was sized to cover the entire Form and sent to the back.
I noticed that some of the Form.BackgroundColor would be mixed in with the outlines of my icons. The icons have transparency along the edges for a smoother appearance. Since the icons are picking up the Form's BackgroundColor, this makes me think that the PictureBoxes are creating new images when the icons are loaded into the form. The semi-transparent portions of the image are then merged with the Form's BackgroundColor when they should merge with whatever colors are behind the form.
http://img838.imageshack.us/img838/8299/whitedesktop.jpg
In this image you can see the Fuchsia existing in the icons even though the Form's Fuchsia color is now completely transparent. I forgot to point out that the same green to yellow gradient with an Alpha value of 150 was used in every case. In the images where the gradient doesn't look green, it's because the transparent colors are blending with the Fuchsia background.
I'm not really sure what to do from here. I feel like I could get what I want if I could somehow make the Form alone completely transparent. I was also thinking I may have better luck just drawing the icons instead of using PictureBoxes. The problem then would be setting up the icons to receive mouse events. (I've never made my own events, and I think it would involved some Win32 API calls.)
Is there something else I can do with the PictureBoxes to get the effect I want? Whichever the case, I'm open to any ideas or suggestions for the overall effect I'm trying to achieve.

This is pretty easy to do in Winforms. What you need is a sandwich of two forms. The bottom one should provide the transparent gradient background, the top one should draw the icons and handle mouse clicks. Some sample code:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
this.TopMost = true;
this.FormBorderStyle = FormBorderStyle.None;
this.TransparencyKey = this.BackColor = Color.Fuchsia;
this.Opacity = 0.3;
var overlay = new Form();
overlay.FormBorderStyle = FormBorderStyle.None;
overlay.TransparencyKey = overlay.BackColor = Color.Fuchsia;
overlay.StartPosition = FormStartPosition.Manual;
overlay.Location = this.Location;
overlay.MouseDown += HandleIconClick;
this.Resize += delegate { overlay.Size = this.Size; };
this.LocationChanged += delegate { overlay.Location = this.Location; };
overlay.Paint += PaintIcons;
this.Paint += PaintBackground;
this.Load += delegate { overlay.Show(this); };
}
private void PaintBackground(object sender, PaintEventArgs e) {
var rc = new Rectangle(0, 0, this.ClientSize.Width, this.ClientSize.Height);
using (var br = new LinearGradientBrush(rc, Color.Gainsboro, Color.Yellow, 0f)) {
e.Graphics.FillRectangle(br, rc);
}
}
private void PaintIcons(object sender, PaintEventArgs e) {
e.Graphics.DrawIcon(Properties.Resources.ExampleIcon1, 50, 30);
// etc...
}
void HandleIconClick(object sender, MouseEventArgs e) {
// TODO
}
}
Which looks like this with the somewhat random colors and icon I selected:

OK, I got a bit lost in all that, but from the description in the original paragraph, I would make sure the background rectangle is NOT the visual parent of the pictureboxes. Make them overlapping siblings, with the pictureboxes in front using Panel.Zindex.
Then you can just change the opacity of the rectangle, without affecting the icons. Also make sure the icon source image files have a transparent background.
Should work I think.

Transparent background on winforms?

I wanted to make my windows form transparent so removed the borders, controls and everything leaving only the forms box, then I tried to the BackColor and TransparencyKey to transparent but it didnt work out as BackColor would not accept transparent color. After searching around I found this at msdn:
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
this.TransparencyKey = BackColor;
Unhappyly it did not work either. I still get the grey or any other selected color background.
All I wanted to do is to have the windows form transparent so I could use a background image that would act as if it was my windows form.
I searched around here and saw many topics in regards opacity which is not what I am looking for and also saw some in regards this method I was trying but have not found an answer yet.
Hope anyone can light my path.
UPDATE:
image removed as problem is solved

The manner I have used before is to use a wild color (a color no one in their right mind would use) for the BackColor and then set the transparency key to that.
this.BackColor = Color.LimeGreen;
this.TransparencyKey = Color.LimeGreen;

A simple solution to get a transparent background in a windows form is to overwrite the OnPaintBackground method like this:
protected override void OnPaintBackground(PaintEventArgs e)
{
//empty implementation
}
(Notice that the base.OnpaintBackground(e) is removed from the function)

I've tried the solutions above (and also) many other solutions from other posts.
In my case, I did it with the following setup:
public partial class WaitingDialog : Form
{
public WaitingDialog()
{
InitializeComponent();
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
// Other stuff
}
protected override void OnPaintBackground(PaintEventArgs e) { /* Ignore */ }
}
As you can see, this is a mix of previously given answers.

Here was my solution:
In the constructors add these two lines:
this.BackColor = Color.LimeGreen;
this.TransparencyKey = Color.LimeGreen;
In your form, add this method:
protected override void OnPaintBackground(PaintEventArgs e)
{
e.Graphics.FillRectangle(Brushes.LimeGreen, e.ClipRectangle);
}
Be warned, not only is this form fully transparent inside the frame, but you can also click through it. However, it might be cool to draw an image onto it and make the form able to be dragged everywhere to create a custom shaped form.

My solution was extremely close to Joel's (Not Etherton, just plain Joel):
public partial class WaitingDialog : Form
{
public WaitingDialog()
{
InitializeComponent();
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
this.TransparencyKey = Color.Transparent; // I had to add this to get it to work.
// Other stuff
}
protected override void OnPaintBackground(PaintEventArgs e) { /* Ignore */ }
}

What works for me is using a specific color instead of the real ability of .png to represent transparency.
So, what you can do is take your background image, and paint the transparent area with a specific color (Magenta always seemed appropriate to me...).
Set the image as the Form's BackgrounImage property, and set the color as the Form's TransparencyKey. No need for changes in the Control's style, and no need for BackColor.
I've tryed it right now and it worked for me...

I tried almost all of this. but still couldn't work.
Finally I found it was because of 24bitmap problems. If you tried some bitmap which less than 24bit. Most of those above methods should work.

I had drawn a splash screen (32bpp BGRA) with "transparent" background color in VS2013 and put a pictureBox in a form for display. For me a combination of above answers worked:
public Form1()
{
InitializeComponent();
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = this.pictureBox1.BackColor;
this.TransparencyKey = this.pictureBox1.BackColor;
}
So make sure you use the same BackColor everywhere and set that color as the TransparencyKey.

C# Application wide color management

im on to write a large C# Application.
The point is that the colors of the controls should be adjustable by the user of the application.
It would be really nice if there are any solution to override(only for the context of this application) the System.Drawing.SystemColors, so that i do not have to set the value of every single control by hand.
Do anybody know an solution for my problem which is that simple?
Thanks

Look at Application Setting bindings. Not sure how you would do this for all controls, but simply recursing through the control tree should be sufficient.

I think your best approach would be to inherit each control and set its default display properties. This would give you a library of the standard WinForms controls that you could easily customize and re-use. More information here (in VB, I couldn't find examples in C#).

You shouldn't need to override the system defaults but you are able to define your own colours.
Color NastyColour = Color.FromArgb(1, 2, 3);
1 = Red
2 = Green
3 = Blue

Unfortunately it's not possible to modify the Windows colour scheme just for your application.
Winforms makes it possible to change things like the background colour for all controls on a form, but for many areas (such as the bevel colours on buttons, or window title bars), you'll probably need to resort to painting the control yourself.

I wrote the code below to do something like this. I'm not particularly happy with it as it needs specialized handling for any controls that are out of the ordinary, but it did the job. I keep an instance of Painter around, and call Apply every time I create a form, passing the form as the argument. It recurses through all the child controls, altering their appearance
public class Painter
{
Color foreColor;
Color backColor;
Color altBackColor;
Color buttonColor;
Font font;
public Painter(Color foreColor, Color backColor, Color altBackColor, Color buttonColor, Font font)
{
this.foreColor=foreColor;
this.backColor=backColor;
this.altBackColor=altBackColor;
this.buttonColor=buttonColor;
this.font=font;
}
public void Apply(Control c)
{
if(c==null)
return;
c.ForeColor = foreColor;
c.BackColor = (c is Button ) ? buttonColor
: backColor;
if (c is DataGridView)
{
var dgv = (DataGridView) c;
dgv.BackgroundColor = BackColor;
dgv.AlternatingRowsDefaultCellStyle.BackColor = altBackColor;
dgv.ColumnHeadersDefaultCellStyle.BackColor = buttonColor;
}
c.Font = font;
foreach(Control child in c.Controls)
Apply(child);
}
}

Spend $1000 and get a copy of DevExpress. We're writing a large application using their framework, and the skinning ability is great.
I know this doesn't sound like the best answer, but if you're looking for application wide skinning ability, a third-party library may be appropriate.

How to make a transparent Image in CF 2.0 without third party libraries?

is there a way, to make a picture transparent in CF2.0? I have to lay a small Image over a textbox, but it has to be transparent so the User can see the text anyway. Do you have an Idea?
Thank you very much
twickl
Edit:
Thanks for your answers, I will check those links out!
To complete my Post, here is what I´m trying to do:
I want to show a small image (the image does not exist yet and I have to make ist, so I´m totaly open for all formats) that is an X on the right end of a textbox. By clicking that X the Text inside the textbox will be erased...like on the iPhone. But I can not build my own control becuse in my Project are so many TextBoxes that are allready custom Controls with the windows TextBox on it, that it will be to much work and testing to switch all of them to custom controls. So I have the Idea to make a small Panel, Picturebox, whatever, that lays above the Textbox. But it has to be transparent. The OS is Windows CE 5.0 with CF 2.0 on it.

Depending on what kind of transparency you need, you might choose any of these options:
1.) If you have an image with a specific portion that should be entirely transparent, you can use ImageAttributes.SetColorKey() to set a single transparent color and then pass this to Graphics.DrawImage. Your image will need to have one color (e.g. Color.Cyan) that will be drawn completely transparent.
2.) If you'd like the entire image to be partially transparent, e.g. for a fade in/fade out effect, you can P/Invoke the AlphaBlend() function, as demonstrated here.
3.) If you have an image with transparency information built in, e.g. a transparent PNG image that needs to be rendered on a variety of background colors, these previous methods will not work and you need to use the COM based IImage interface.
The COM interop from .NETCF is documented on this page (search for "IImage interface" on that page).
Option 3 is the most flexible, but it also involves the most implementation effort. If you follow up with more information about the kind of image you want to draw transparently and your target platform, we might be able to help more.

I did it by deriving a class from PictureBox and handling OnPaint. The key is the ImageAttributes object passed to DrawImage. I'm assuming pixel 0,0 is the transparent color, but you could handle that differently.
public partial class TransparentPictureBox : PictureBox
{
private Color tColor;
public TransparentPictureBox()
{
InitializeComponent();
}
public new Image Image
{
get { return base.Image; }
set
{
if (value == base.Image)
return;
if (value != null)
{
Bitmap bmp = new Bitmap(value);
tColor = bmp.GetPixel(0, 0);
this.Width = value.Width;
this.Height = value.Height;
}
base.Image = value;
}
}
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.Clear(this.BackColor);
if (Image == null)
return;
ImageAttributes attr = new ImageAttributes();
// Set the transparency color.
attr.SetColorKey(tColor, tColor);
Rectangle dstRect = new Rectangle(0, 0, base.Image.Width, base.Image.Height);
e.Graphics.DrawImage(base.Image, dstRect, 0, 0, base.Image.Width, base.Image.Height, GraphicsUnit.Pixel, attr);
}
}