C# – Prevent context menu from appearing when clicking on blank part of datagrid

cdatagridview

When right clicking on the empty part of a DataGridView in C# (clicking on a part of the grid that contains no rows) the context menu still appears with it's row based options. How can I only have the context menu appear when the click falls over a row?

This is as far as I have gotten:

    private void f_context_select_row(object sender, MouseEventArgs e)
    {

            if (e.Button == MouseButtons.Right)
            {

                var hti = jobs_datagrid.HitTest(e.X, e.Y);
                if (hti.RowIndex >= 0)
                {
                    jobs_datagrid.ClearSelection();
                    jobs_datagrid.Rows[hti.RowIndex].Selected = true;
                }
                else
                {
                    //what can I do here to collapse the context menu?
                }
            }

    }

I am programatically building the Datagrid and context menu like this:

                    //on right click select row
                    jobs_datagrid.MouseDown += new MouseEventHandler(f_context_select_row);

                    //generate context menu
                    ContextMenuStrip m = new ContextMenuStrip();

                    ToolStripMenuItem context_datagrid_run = new ToolStripMenuItem("Run All Selected Campaigns");
                    ToolStripMenuItem context_datagrid_edit = new ToolStripMenuItem("Edit This Campaign");
                    ToolStripMenuItem context_datagrid_delete = new ToolStripMenuItem("Delete This Campaign");
                    context_datagrid_delete.Click += f_context_datagrid_delete;
                    context_datagrid_run.Click += f_run_selected_campaigns;
                    context_datagrid_edit.Click += f_context_datagrid_edit;

                    m.Items.Add(context_datagrid_delete);
                    m.Items.Add(context_datagrid_run);
                    m.Items.Add(context_datagrid_edit);
                    jobs_datagrid.ContextMenuStrip = m;

                    splitContainer3.Panel2.Controls.Add(jobs_datagrid);

Best Answer

what about the ContextMenuStrip.Opening event?

private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
        {
            var cms = sender as ContextMenuStrip;
            var mousepos = Control.MousePosition;
            if (cms != null)
            {
                var rel_mousePos = cms.PointToClient(mousepos);
                if (cms.ClientRectangle.Contains(rel_mousePos))
                {
                    //the mouse pos is on the menu ... 
                    //looks like the mouse was used to open it
                    var dgv_rel_mousePos = dataGridView1.PointToClient(mousepos);
                    var hti = dataGridView1.HitTest(dgv_rel_mousePos.X, dgv_rel_mousePos.Y);
                    if (hti.RowIndex == -1)
                    { 
                        // no row ...
                        e.Cancel = true;
                    }
                }
                else
                {
                    //looks like the menu was opened without the mouse ...
                    //we could cancel the menu, or perhaps use the currently selected cell as reference...
                    e.Cancel = true;
                }
            }
        }

Related Solutions

C# – How to show a Context Menu when you right click a Menu Item

Edit, due to a comment:

In:

protected override void OnClick(EventArgs e)
{
    if (SecondaryContextMenu == null || MouseButtons != MouseButtons.Right)
    {
        base.OnClick(e);
    }
}

this part

 MouseButtons != MouseButtons.Right

should and does compile as it is a call to Control.MouseButtons. Since the Form inherits Control class, it is sufficient to call MouseButtons property directly.

Hope this helps:

public partial class Form1 : Form
{
    class CustomToolStripMenuItem : ToolStripMenuItem
    {
        private ContextMenuStrip secondaryContextMenu;

        public ContextMenuStrip SecondaryContextMenu
        {
            get
            {
                return secondaryContextMenu;
            }
            set
            {
                secondaryContextMenu = value;
            }
        }

        public CustomToolStripMenuItem(string text)
            : base(text)
        { }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (secondaryContextMenu != null)
                {
                    secondaryContextMenu.Dispose();
                    secondaryContextMenu = null;
                }
            }

            base.Dispose(disposing);
        }

        protected override void OnClick(EventArgs e)
        {
            if (SecondaryContextMenu == null || MouseButtons != MouseButtons.Right)
            {
                base.OnClick(e);
            }
        }
    }

    class CustomContextMenuStrip : ContextMenuStrip
    {
        private bool secondaryContextMenuActive = false;
        private ContextMenuStrip lastShownSecondaryContextMenu = null;

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (lastShownSecondaryContextMenu != null)
                {
                    lastShownSecondaryContextMenu.Close();
                    lastShownSecondaryContextMenu = null;
                }
            }
            base.Dispose(disposing);
        }

        protected override void OnControlAdded(ControlEventArgs e)
        {
            e.Control.MouseClick += new MouseEventHandler(Control_MouseClick);
            base.OnControlAdded(e);
        }

        protected override void OnControlRemoved(ControlEventArgs e)
        {
            e.Control.MouseClick -= new MouseEventHandler(Control_MouseClick);
            base.OnControlRemoved(e);
        }

        private void Control_MouseClick(object sender, MouseEventArgs e)
        {
            ShowSecondaryContextMenu(e);
        }

        protected override void OnMouseClick(MouseEventArgs e)
        {
            ShowSecondaryContextMenu(e);
            base.OnMouseClick(e);
        }

        private bool ShowSecondaryContextMenu(MouseEventArgs e)
        {
            CustomToolStripMenuItem ctsm = this.GetItemAt(e.Location) as CustomToolStripMenuItem;

            if (ctsm == null || ctsm.SecondaryContextMenu == null || e.Button != MouseButtons.Right)
            {
                return false;
            }

            lastShownSecondaryContextMenu = ctsm.SecondaryContextMenu;
            secondaryContextMenuActive = true;
            ctsm.SecondaryContextMenu.Closed += new ToolStripDropDownClosedEventHandler(SecondaryContextMenu_Closed);
            ctsm.SecondaryContextMenu.Show(Cursor.Position);
            return true;
        }

        void SecondaryContextMenu_Closed(object sender, ToolStripDropDownClosedEventArgs e)
        {
            ((ContextMenuStrip)sender).Closed -= new ToolStripDropDownClosedEventHandler(SecondaryContextMenu_Closed);
            lastShownSecondaryContextMenu = null;
            secondaryContextMenuActive = false;
            Focus();
        }

        protected override void OnClosing(ToolStripDropDownClosingEventArgs e)
        {
            if (secondaryContextMenuActive)
            {
                e.Cancel = true;
            }

            base.OnClosing(e);
        }
    }

    public Form1()
    {
        InitializeComponent();


        CustomToolStripMenuItem itemPrimary1 = new CustomToolStripMenuItem("item primary 1");
        itemPrimary1.SecondaryContextMenu = new ContextMenuStrip();
        itemPrimary1.SecondaryContextMenu.Items.AddRange(new ToolStripMenuItem[] { 
            new ToolStripMenuItem("item primary 1.1"),
            new ToolStripMenuItem("item primary 1.2"),
        });

        CustomToolStripMenuItem itemPrimary2 = new CustomToolStripMenuItem("item primary 2");
        itemPrimary2.DropDownItems.Add("item primary 2, sub 1");
        itemPrimary2.DropDownItems.Add("item primary 2, sub 2");
        itemPrimary2.SecondaryContextMenu = new ContextMenuStrip();
        itemPrimary2.SecondaryContextMenu.Items.AddRange(new ToolStripMenuItem[] { 
            new ToolStripMenuItem("item primary 2.1"),
            new ToolStripMenuItem("item primary 2.2"),
        });

        CustomContextMenuStrip primaryContextMenu = new CustomContextMenuStrip();
        primaryContextMenu.Items.AddRange(new ToolStripItem[]{
            itemPrimary1,
            itemPrimary2
        });

        this.ContextMenuStrip = primaryContextMenu;
    }
}

C# – right click context menu for datagridview

You can use the CellMouseEnter and CellMouseLeave to track the row number that the mouse is currently hovering over.

Then use a ContextMenu object to display you popup menu, customised for the current row.

Here's a quick and dirty example of what I mean...

private void dataGridView1_MouseClick(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Right)
    {
        ContextMenu m = new ContextMenu();
        m.MenuItems.Add(new MenuItem("Cut"));
        m.MenuItems.Add(new MenuItem("Copy"));
        m.MenuItems.Add(new MenuItem("Paste"));

        int currentMouseOverRow = dataGridView1.HitTest(e.X,e.Y).RowIndex;

        if (currentMouseOverRow >= 0)
        {
            m.MenuItems.Add(new MenuItem(string.Format("Do something to row {0}", currentMouseOverRow.ToString())));
        }

        m.Show(dataGridView1, new Point(e.X, e.Y));

    }
}

Best Answer

Related Solutions

C# – How to show a Context Menu when you right click a Menu Item

C# – right click context menu for datagridview

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