Для этого потребуется другая форма, которую вы отображаете поверх существующей.Его свойство Opacity может создать желаемый эффект.Добавьте новый класс в ваш проект и вставьте код, показанный ниже.Вызовите метод Close (), чтобы снова удалить эффект.
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
class Plexiglass : Form {
public Plexiglass(Form tocover) {
this.BackColor = Color.DarkGray;
this.Opacity = 0.30; // Tweak as desired
this.FormBorderStyle = FormBorderStyle.None;
this.ControlBox = false;
this.ShowInTaskbar = false;
this.StartPosition = FormStartPosition.Manual;
this.AutoScaleMode = AutoScaleMode.None;
this.Location = tocover.PointToScreen(Point.Empty);
this.ClientSize = tocover.ClientSize;
tocover.LocationChanged += Cover_LocationChanged;
tocover.ClientSizeChanged += Cover_ClientSizeChanged;
this.Show(tocover);
tocover.Focus();
// Disable Aero transitions, the plexiglass gets too visible
if (Environment.OSVersion.Version.Major >= 6) {
int value = 1;
DwmSetWindowAttribute(tocover.Handle, DWMWA_TRANSITIONS_FORCEDISABLED, ref value, 4);
}
}
private void Cover_LocationChanged(object sender, EventArgs e) {
// Ensure the plexiglass follows the owner
this.Location = this.Owner.PointToScreen(Point.Empty);
}
private void Cover_ClientSizeChanged(object sender, EventArgs e) {
// Ensure the plexiglass keeps the owner covered
this.ClientSize = this.Owner.ClientSize;
}
protected override void OnFormClosing(FormClosingEventArgs e) {
// Restore owner
this.Owner.LocationChanged -= Cover_LocationChanged;
this.Owner.ClientSizeChanged -= Cover_ClientSizeChanged;
if (!this.Owner.IsDisposed && Environment.OSVersion.Version.Major >= 6) {
int value = 1;
DwmSetWindowAttribute(this.Owner.Handle, DWMWA_TRANSITIONS_FORCEDISABLED, ref value, 4);
}
base.OnFormClosing(e);
}
protected override void OnActivated(EventArgs e) {
// Always keep the owner activated instead
this.BeginInvoke(new Action(() => this.Owner.Activate()));
}
private const int DWMWA_TRANSITIONS_FORCEDISABLED = 3;
[DllImport("dwmapi.dll")]
private static extern int DwmSetWindowAttribute(IntPtr hWnd, int attr, ref int value, int attrLen);
}