C# WINFORM 強制讓窗體獲得焦點(可實現單次置頂或持續置頂)

//首先要說明的是與TopMost的效果不同，TopMost是屬性定義，而且設置True后，如果不設為Flase則一直置頂，效果很差，

//以下方法解決了TopMost使用上的不足

//調用API
[System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, ExactSpelling = true)]
public static extern IntPtr GetForegroundWindow(); //獲得本窗體的句柄
[System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]
public static extern bool SetForegroundWindow(IntPtr hWnd);//設置此窗體為活動窗體
//定義變量,句柄類型
public IntPtr Handle1;

//在窗體加載的時候給變量賦值,即將當前窗體的句柄賦給變量

void Form1_Load(object sender, EventArgs e)
{
Handle1 = this.Handle;
timer2.Enabled = true;
}

//加載一個定時器控件,驗證當前WINDOWS句柄是否和本窗體的句柄一樣,如果不一樣,則激活本窗體

private void timer2_Tick(object sender, EventArgs e)
{
if (Handle1 != GetForegroundWindow()) //持續使該窗體置為最前,屏蔽該行則單次置頂
{
SetForegroundWindow(Handle1);

//timer2.Stop();//此處可以關掉定時器，則實現單次置頂
}
}

 

示例代碼：

namespace WinFormsApp_GetForegroundWindowTest
{
    public partial class Form1 : Form
    {
        //調用API
        [System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, ExactSpelling = true)]
        public static extern IntPtr GetForegroundWindow(); //獲得本窗體的句柄
        [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]
        public static extern bool SetForegroundWindow(IntPtr hWnd);//設置此窗體為活動窗體
        //定義變量,句柄類型
        public IntPtr Handle1;
        Timer timer2 = new Timer();

        public Form1()
        {
            InitializeComponent();
        }

        Form Form2;

        //在窗體加載的時候給變量賦值,即將當前窗體的句柄賦給變量
        void Form1_Load(object sender, EventArgs e)
        {
            Handle1 = this.Handle;
            timer2.Tick += new EventHandler(timer2_Tick);
            timer2.Interval = 1000;
        }

        //加載一個定時器控件,驗證當前WINDOWS句柄是否和本窗體的句柄一樣,如果不一樣,則激活本窗體
        private void timer2_Tick(object sender, EventArgs e)
        {
            //if (Handle1 != GetForegroundWindow()) //持續使該窗體置為最前,屏蔽該行則單次置頂
            //{
            SetForegroundWindow(Handle1);
            timer2.Stop();//此處可以關掉定時器，則實現單次置頂
            //}
        }

        private void btnSetForm2ToTop_Click(object sender, EventArgs e)
        {
            if (Form2 == null) return;

            timer2.Enabled = true;
            Handle1 = Form2.Handle;
        }

        private void btn_OpenForm2_Click(object sender, EventArgs e)
        {
            Form2 = new Form();
            Form2.Text = "Form2";
            Form2.Show();
        }
    }
}