GDI對象內存泄漏：ContextMenuStrip中的自定義ToolStripControlHost沒有處理

Question

我有各種基於ToolStripControlHost的自定義上下文菜單。 它們包裝在ContextMenuStrip中，並放置在DataGridView列的標頭中（取決於某些條件），如下所示：

        if (this.DGV.Columns[DGVColname] != null)
        {
            ContextMenuStrip cstr = null;
            // there is always only one item in context menu
            // I tried disposing in different manners, this is an example of my efforts
            if (this.DGV.Columns[DGVColname].HeaderCell.ContextMenuStrip != null)
            {
                cstr = this.DGV.Columns[DGVColname].HeaderCell.ContextMenuStrip;

                if (cstr.Items[0] != null)
                {
                    cstr.Items[0].Dispose();
                    cstr.Items.Clear();
                }
            }
            else
            {
                cstr = new ContextMenuStrip();
                cstr.Opened += new EventHandler(cstr_Opened);
            }

            TextBoxToolStrip tsHost = new TextBoxToolStrip();

            tsHost.Size = new System.Drawing.Size(172, 20);
            tsHost.TextChanged += new EventHandler(myToolStrip_TextChanged);

            cstr.ShowCheckMargin = false;
            cstr.ShowImageMargin = false;
            cstr.Margin = new Padding(0);
            cstr.Padding = new Padding(0);
            cstr.Items.Add(tsHost);

            cstr.MaximumSize = new Size(tsHost.Width + 10, tsHost.Height + 10);
            cstr.Size = cstr.MaximumSize;
            cstr.LayoutStyle = ToolStripLayoutStyle.Flow;

            DGV.Columns[DGVColname].HeaderCell.ContextMenuStrip = cstr;
        }

盡管調用了dispose和/或進行了任何設置，但我可以使我的應用程序處理的GDI對象數仍然為零，並且仍在穩定增長。 我的DataGridView中有20個帶有菜單的列，每次調用該代碼時，都會得到+30或+34（准確）。

在此示例中，TextBoxToolStrip擴展了ToolStripControlHost並包含單個TextBox：

   public class TextBoxToolStrip : ToolStripControlHost
    {
        // .... some string or bool Properties here ....

        public TextBox TextBoxControl
        {
            get { return Control as TextBox; }
        }

        public TextBoxToolStrip()
            : base(new TextBox())
        {
            this.TextBoxControl.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
            | System.Windows.Forms.AnchorStyles.Right)));

            this.TextBoxControl.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.TextBoxControl.Location = new System.Drawing.Point(0, 3);
            this.TextBoxControl.ReadOnly = false;
            this.TextBoxControl.Font =
                new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(238)));

            this.TextBoxControl.Size = new System.Drawing.Size(172, 20);
            this.Size = new System.Drawing.Size(172, 20);

            this.TextBoxControl.TabIndex = 0;
            this.TextBoxControl.TextAlign = System.Windows.Forms.HorizontalAlignment.Left;

            this.MouseHover += new EventHandler(TextBoxToolStrip_Enter);

            this.AutoSize = false;
            this.TextBoxControl.PreviewKeyDown += new PreviewKeyDownEventHandler(TextBoxPreviewKeyDown);
            this.TextBoxControl.KeyDown += new KeyEventHandler(TextBoxControl_KeyDown);
        }

        protected override void OnSubscribeControlEvents(Control control)
        {
            base.OnSubscribeControlEvents(control);

            TextBox tb = control as TextBox;

            if (tb != null)
            {
                tb.TextChanged += new EventHandler(OnTextChanged);
            }
        }

        protected override void OnUnsubscribeControlEvents(Control control)
        {
            base.OnUnsubscribeControlEvents(control);

            TextBox tb = control as TextBox;

            if (tb != null)
            {
                tb.TextChanged -= OnTextChanged;
            }
        }

        private void TextBoxToolStrip_Enter(object sender, EventArgs e)
        {
            this.Focus();
        }

        private void TextBoxPreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            if (e.KeyCode == Keys.Menu)
                e.IsInputKey = true;
        }

        private void TextBoxControl_KeyDown(object sender, KeyEventArgs e)
        {
            TextBox txb = sender as TextBox;
            ToolStripDropDown tsd = (ToolStripDropDown)txb.Parent;

            if (e.KeyCode == Keys.Enter)
            {
                tsd.Close();
            }
        }

        /// <summary>
        /// Expose TextChanged event
        /// </summary>
        public new event EventHandler TextChanged;

        private void OnTextChanged(object sender, EventArgs e)
        {
            if (TextChanged != null)
            {
                TextChanged(this, e);
            }
        }

題：

如何正確處理上下文菜單？

Answer 1

事實證明，它不是事件，靜態引用或任何常見的東西。 我在TreeView上看到了ToolStripControlHosts，發現只有那些在泄漏。 看來TreeView會很高興地自行泄漏資源：當CheckBoxes屬性設置為true時，用於處理選中和未選中復選框的位圖的句柄在處理TreeView時不會正確釋放（每次在我的視圖中都剩下4個）情況），這會導致GDI對象內存泄漏。 我不得不手動處理復選框圖像列表。

這里描述了問題和解決方案。 盡管我在這里使用屬性而不是事件：

        public new bool CheckBoxes
        {
            get
            {
                return base.CheckBoxes;
            }
            set
            {
                if (base.CheckBoxes == false)
                {
                    base.CheckBoxes = true;

                    IntPtr handle = SendMessage(this.Handle, TVM_GETIMAGELIST, new
                    IntPtr(TVSIL_STATE), IntPtr.Zero);
                        if (handle != IntPtr.Zero)
                            _checkboxImageList = handle;
                }
            }
        }

在我的情況下，StyleChanged事件不起作用。