如何关闭表格？

Question

I have this code which Show/open a new Form :

In the gkh_Keydown event when i click on Ctrl + M it's showing/opening the new Form . Now i want to do that when i click again Ctrl + M it will close the new Form .

When i click once to open the new Form it's going to this Form first :

public MagnifierMainForm(bool showMain)
        {
            InitializeComponent();

            if (showMain == true)
            {

                GetConfiguration();

                //--- My Init ---
                FormBorderStyle = FormBorderStyle.None;
                TopMost = true;
                StartPosition = FormStartPosition.CenterScreen;

                mImageMagnifierMainControlPanel = Properties.Resources.magControlPanel20061222;

                if (mImageMagnifierMainControlPanel == null)
                    throw new Exception("Resource cannot be found!");

                Width = mImageMagnifierMainControlPanel.Width;
                Height = mImageMagnifierMainControlPanel.Height;

                HotSpot hsConfiguration = new HotSpot(new Rectangle(50, 15, 35, 30));
                hsConfiguration.OnMouseDown += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseDown);
                hsConfiguration.OnMouseUp += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseUp);
                hsConfiguration.OnMouseMove += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseMove);

                HotSpot hsMagnfier = new HotSpot(new Rectangle(10, 15, 30, 30));
                hsMagnfier.OnMouseMove += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseMove);
                hsMagnfier.OnMouseDown += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseDown);
                hsMagnfier.OnMouseUp += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseUp);

                HotSpot hsExit = new HotSpot(new Rectangle(95, 20, 15, 15));
                hsExit.OnMouseUp += new HotSpot.MouseEventDelegate(hsExit_OnMouseUp);

                mHotSpots.Add(hsConfiguration);
                mHotSpots.Add(hsMagnfier);
                mHotSpots.Add(hsExit);

                ShowInTaskbar = false;
                this.Show();
            }
            else
            {
                GetConfiguration();
                int x = mLastCursorPosition.X;
                int y = mLastCursorPosition.Y;
                MagnifierForm magnifier = new MagnifierForm(mConfiguration, System.Windows.Forms.Cursor.Position);//mLastCursorPosition);                
                magnifier.Show();
            }

        }

And since i did false it's doing the else part :

GetConfiguration();
                    int x = mLastCursorPosition.X;
                    int y = mLastCursorPosition.Y;
                    MagnifierForm magnifier = new MagnifierForm(mConfiguration, System.Windows.Forms.Cursor.Position);//mLastCursorPosition);                
                    magnifier.Show();

magnifier.Show(); do show the new Form .

Now i want that if i do Ctrl + M again it will close the Form magnifier.Show();

So in the Form in the gkh_KeyDown event in the else part i did :

magnifierform.Close();

Added a new variable this time only for magnifierform and try to close it. So in magnifierform i did :

public MagnifierForm(Configuration configuration, Point startPoint)
        {
            InitializeComponent();

            //--- My Init ---
            mConfiguration = configuration;
            FormBorderStyle = FormBorderStyle.None;

            ShowInTaskbar = mConfiguration.ShowInTaskbar;
            TopMost = mConfiguration.TopMostWindow;
            Width = mConfiguration.MagnifierWidth;
            Height = mConfiguration.MagnifierHeight;

            // Make the window (the form) circular
            GraphicsPath gp = new GraphicsPath();
            gp.AddEllipse(ClientRectangle);
            Region = new Region(gp);

            mImageMagnifier = Properties.Resources.magnifierGlass;

            mTimer = new Timer();
            mTimer.Enabled = true;
            mTimer.Interval = 20;
            mTimer.Tick += new EventHandler(HandleTimer);

            mScreenImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width,
                                     Screen.PrimaryScreen.Bounds.Height);
            mStartPoint = startPoint;
            mTargetPoint = startPoint;

            if (mConfiguration.ShowInTaskbar)
                ShowInTaskbar = true;
            else
                ShowInTaskbar = false;
        }

        public MagnifierForm()
        {

        }

Added another instance that does nothing sincei only want to close it. But it never closed .

magnifierform is a variable of the MagnifierForm form i want to close it directly and not as before i used the other form MagnifierMainForm.

I just want to close it but it never closed. I used a breakpoint on the line :

magnifierform.Close();

On second Ctrl + M it's getting there but it dosen't close the MagnifierForm . Just does nothing.

EDIT

Tried something else now in the MagnifierForm i added :

public MagnifierForm()
        {
            this.Close();
        }

In Form1 in the gkh_KeyDown event in the else side i changed it to :

else
                {
                    magnifierform = new MagnifierForm();
                }

So the instance i'm doing it on the second Ctrl + M And again the breakpoint stop there but when i do continue it's not closing the Form .

Answer 1

So, if MagnifierMainForm() is already open you want to close it?...otherwise create a new instance and show it? In your code that fires when Ctrl+M is pressed, do something like:

        Form frmToClose = null;
        foreach (Form frm in Application.OpenForms)
        {
            if (frm is MagnifierMainForm)
            {
                frmToClose = frm;
                break;
            }
        }
        if (frmToClose != null)
        {
            frmToClose.Close();
        }
        else
        {
            // create a new instance of MagnifierMainForm() and display it
        }

Answer 2

使用此方法form.Dispose();