淡出一个面板 - Windows窗体 [英] Fade a panel- Windows forms

问题描述

我有一个细节面板，可以显示或隐藏。

I have a details panel which can be shown or hidden.

如何才能做一个简单的淡入淡出效果的显示/隐藏该面板（当然它的内容和）？

How can I made a simple fade effect for showing/hiding that panel (and of course its contents) ?

我使用Windows窗体和控件没有透明度 Windows窗体属性。

I am using Windows forms, and controls don't have opacity property in windows forms.

推荐答案

这是非常做，能在的WinForms，它只有的看的像一个褪色。一种技术是使用Control.DrawToBitmap（）来创建控制的一个位图。然后从背景位图融合的前景位图与一个计时器。

This is quite do-able in Winforms, it only has to look like a fade. One technique is to use Control.DrawToBitmap() to create a bitmap of the control. And then blend from a background bitmap to the foreground bitmap with a timer.

我将使用一个小组的用户控件，而不是因此可以通过设计与设计师的WinForms控制。在code将在任何类型的控制。但是工作。添加一个新类到您的项目并粘贴下面所示的code。编译。创建自己的用户控件从这一带项目+添加新项，Windows窗体节点，继承用户控制模板，并从弹出的列表中选择FadeControl。设计用户控件是正常的。

I'll use a UserControl instead of a Panel so you can design the control with the Winforms designer. The code will however work in any kind of control. Add a new class to your project and paste the code shown below. Compile. Create your own UserControl from this one with Project + Add New Item, Windows Forms node, "Inherited User Control" template and pick FadeControl from the popup list. Design the user control as normal.

按照规定，控制会自动从父母的背景色渐变为控制内容，只要你的控件添加到父。呼叫淡出（），使之融入回到后台。如果你想自动配置的控制，当它完成褪色传递真实的。您可以使用淡入（）和手动控制褪色的褪色性。您可以在注释以//可修改调整动画的线条调整数。额外的工作，需要如果父具有非不透明的背景

As written, the control will automatically fade from the parent's BackColor to the control content as soon as you add the control to the parent. Call FadeOut() to make it blend back to the background. Pass true if you want to automatically dispose the control when it is done fading. You can use FadeIn() and the Faded property for manual control of the fading. You can adjust the numbers in the lines commented with // tweakable to adjust the animation. Additional work is needed if the parent has a non-opaque background.

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;

class FadeControl : UserControl {

    public FadeControl() {
        pbox = new PictureBox();
        pbox.BorderStyle = BorderStyle.None;
        pbox.Paint += new PaintEventHandler(pbox_Paint);
        fadeTimer = new Timer();
        fadeTimer.Interval = 15;   // tweakable
        fadeTimer.Tick += new EventHandler(fadeTimer_Tick);
    }

    public bool Faded {
        get { return blend < 0.5f; }
    }
    public void FadeIn() {
        stopFade(false);
        createBitmaps();
        startFade(1);
    }
    public void FadeOut(bool disposeWhenDone) {
        stopFade(false);
        createBitmaps();
        disposeOnComplete = disposeWhenDone;
        startFade(-1);
    }

    private void createBitmaps() {
        bmpBack = new Bitmap(this.ClientSize.Width, this.ClientSize.Height);
        using (var gr = Graphics.FromImage(bmpBack)) gr.Clear(this.Parent.BackColor);
        bmpFore = new Bitmap(bmpBack.Width, bmpBack.Height);
        this.DrawToBitmap(bmpFore, this.ClientRectangle);
    }
    void fadeTimer_Tick(object sender, EventArgs e) {
        blend += blendDir * 0.02F;   // tweakable
        bool done = false;
        if (blend < 0) { done = true; blend = 0; }
        if (blend > 1) { done = true; blend = 1; }
        if (done) stopFade(true); 
        else pbox.Invalidate();
    }
    void pbox_Paint(object sender, PaintEventArgs e) {
        Rectangle rc = new Rectangle(0, 0, pbox.Width, pbox.Height);
        ColorMatrix cm = new ColorMatrix();
        ImageAttributes ia = new ImageAttributes();
        cm.Matrix33 = blend;
        ia.SetColorMatrix(cm);
        e.Graphics.DrawImage(bmpFore, rc, 0, 0, bmpFore.Width, bmpFore.Height, GraphicsUnit.Pixel, ia);
        cm.Matrix33 = 1F - blend;
        ia.SetColorMatrix(cm);
        e.Graphics.DrawImage(bmpBack, rc, 0, 0, bmpBack.Width, bmpBack.Height, GraphicsUnit.Pixel, ia);
    }

    private void stopFade(bool complete) {
        fadeTimer.Enabled = false;
        if (complete) {
           if (!Faded) this.Controls.Remove(pbox);
           else if (disposeOnComplete) this.Dispose();
        }
        if (bmpBack != null) { bmpBack.Dispose(); bmpBack = null; }
        if (bmpFore != null) { bmpFore.Dispose(); bmpFore = null; }
    }
    private void startFade(int dir) {
        this.Controls.Add(pbox);
        this.Controls.SetChildIndex(pbox, 0);
        blendDir = dir;
        fadeTimer.Enabled = true;
        fadeTimer_Tick(this, EventArgs.Empty);
    }

    protected override void OnCreateControl() {
        base.OnCreateControl();
        if (!DesignMode) FadeIn();
    }
    protected override void OnResize(EventArgs eventargs) {
        pbox.Size = this.ClientSize;
        base.OnResize(eventargs);
    }
    protected override void Dispose(bool disposing) {
        if (disposing) {
            stopFade(false);
            pbox.Dispose();
            fadeTimer.Dispose();
        }
        base.Dispose(disposing);
    }

    private PictureBox pbox;
    private Timer fadeTimer;
    private Bitmap bmpBack, bmpFore;
    private float blend;
    private int blendDir = 1;
    private bool disposeOnComplete;
}

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