Question

Hi I was trying to get a transparent form like a glass which could enable clickthrough and every mouse event to pass to the windows or items behind the glass.

So this is the code I wrote with WindowForms:

namespace ClickThroughMe
{
public partial class ClickThroughForm : Form

{
    private int currentWindowStyle;

    public ClickThroughForm()

    {
        InitializeComponent();
    }

    private void ClickThroughForm_Load(object sender, EventArgs e)

    {
        // Grab the Extended Style information for this window and store it.

        currentWindowStyle = WindowLibrary.User32Wrappers.GetWindowLong(this.Handle, User32Wrappers.GWL.ExStyle);

        // Set our window to "transparent", or invisible to the mouse.

        SetFormToTransparent();

        // Make our window the top-most form.

        this.TopMost = true;       
    }

    private void SetFormToTransparent()

    {
        // This creates a new extended style for our window, making it transparent to the mouse.

        User32Wrappers.SetWindowLong(this.Handle, User32Wrappers.GWL.ExStyle,

                                    (User32Wrappers.WS_EX) currentWindowStyle | 

                                     User32Wrappers.WS_EX.Layered |

                                     User32Wrappers.WS_EX.Transparent);
    }
  }
}

The problem with this code is that whole window get transparent through opacity but controls such buttons or sliders do not retain clickability.

So I need help to make it better.

1)Retain controls Full Opacity (Not needed but important)

2)Retain controls Clickability and Operativity (MUST)

I accept any solution, even changing the project to WPF if this can help getting the result.

Thanks for you time.

Answer 1

Try setting the Form.TransparencyKey Property of the ClickThroughForm to match the forms BackColor.

I tested this when the ClickThroughForm was set to TopMost over another Form and I could fire Button events and the TrackBar control seemed to function correctly.

Note: Using this method no mouse events can be captured by the ClickThroughForm due to its transparency, if this is a requirement then you can disregard this answer.

ClickThroughForm Class

public class ClickThroughForm : Form
{
    private System.ComponentModel.IContainer components = null;

    public ClickThroughForm()
    {
        InitializeComponent();
    }

    private void InitializeComponent()
    {
        this.SuspendLayout();
        // 
        // ClickThroughForm
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(300, 300);
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
        this.Name = "ClickThroughForm";
        this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
        this.Text = "ClickThroughForm";

        //Set the TransparencyKey to match the default BackColor of the Form
        this.TransparencyKey = System.Drawing.SystemColors.Control;

        this.ResumeLayout(false);

    }

    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }
}

Hope this helps you.

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