【原创】如何实现无标题栏窗体的点击任务栏最小化功能

问题的解决

有时候实现一些自定义样式的窗体时，我们会将FormBorderStyle设置为None,这时候发现点击任务栏的窗口，窗口不会自己最小化了，其实给窗体重载一个属性可以解决这个问题

   /// <summary>
        /// 重载该属性实现点击任务栏可以最小化窗体
        /// </summary>
        protected override CreateParams CreateParams
        {
            get
            {
                const int MINIMIZEBOX = 0x00020000;   
                CreateParams para = base.CreateParams;
                para.Style = para.Style | MINIMIZEBOX;
                return para;
            }
        } 

实现原理

1、先上一段通过反编译System.Windows.Form.dll里面的代码，这段代码可以在Form类里面找到

protected override CreateParams CreateParams
{
    [SecurityPermission(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
    get
    {
        CreateParams createParams = base.CreateParams;
        if (base.IsHandleCreated && ((base.WindowStyle & 0x8000000) != 0))
        {
            createParams.Style |= 0x8000000;
        }
        else if (this.TopLevel)
        {
            createParams.Style &= -134217729;
        }
        if (this.TopLevel && (this.formState[FormStateLayered] != 0))
        {
            createParams.ExStyle |= 0x80000;
        }
        IWin32Window window = (IWin32Window) base.Properties.GetObject(PropDialogOwner);
        if (window != null)
        {
            createParams.Parent = Control.GetSafeHandle(window);
        }
        this.FillInCreateParamsBorderStyles(createParams);
        this.FillInCreateParamsWindowState(createParams);
        this.FillInCreateParamsBorderIcons(createParams);
        if (this.formState[FormStateTaskBar] != 0)
        {
            createParams.ExStyle |= 0x40000;
        }
        FormBorderStyle formBorderStyle = this.FormBorderStyle;
        if (!this.ShowIcon && (((formBorderStyle == FormBorderStyle.Sizable) || (formBorderStyle == FormBorderStyle.Fixed3D)) || (formBorderStyle == FormBorderStyle.FixedSingle)))
        {
            createParams.ExStyle |= 1;
        }
        if (this.IsMdiChild)
        {
            if (base.Visible && ((this.WindowState == FormWindowState.Maximized) || (this.WindowState == FormWindowState.Normal)))
            {
                Form form = (Form) base.Properties.GetObject(PropFormMdiParent);
                Form activeMdiChildInternal = form.ActiveMdiChildInternal;
                if ((activeMdiChildInternal != null) && (activeMdiChildInternal.WindowState == FormWindowState.Maximized))
                {
                    createParams.Style |= 0x1000000;
                    this.formState[FormStateWindowState] = 2;
                    base.SetState(0x10000, true);
                }
            }
            if (this.formState[FormStateMdiChildMax] != 0)
            {
                createParams.Style |= 0x1000000;
            }
            createParams.ExStyle |= 0x40;
        }
        if (this.TopLevel || this.IsMdiChild)
        {
            this.FillInCreateParamsStartPosition(createParams);
            if ((createParams.Style & 0x10000000) != 0)
            {
                this.formState[FormStateShowWindowOnCreate] = 1;
                createParams.Style &= -268435457;
            }
            else
            {
                this.formState[FormStateShowWindowOnCreate] = 0;
            }
        }
        if (this.IsRestrictedWindow)
        {
            createParams.Caption = this.RestrictedWindowText(createParams.Caption);
        }
        if ((this.RightToLeft == RightToLeft.Yes) && this.RightToLeftLayout)
        {
            createParams.ExStyle |= 0x500000;
            createParams.ExStyle &= -28673;
        }
        return createParams;
    }
}

可以看到，这里面窗体类通过重载这个属性，判断自身一些样式设置，返回一个参数，这个参数描述了窗体本身的很多样式信息。

显然如果在自己的窗体中重载这个属性，然后在基类原来实现的基础上，再增加一个允许最小化的属性，应该就能解决这个问题。

查手册找到最小化事件的数值为0x00020000，于是就有了刚开始的代码。