UITypeEditor无法正确关闭

Question

I am using a UserControl with a UITypeEditor. The user control has OK and Cancel buttons that do nothing except display a MessageBox with either OK or Cancel and then hide the user control. But when I click one of the buttons, the PropertyGrid displays an empty box where the UserControl was until I click away. Then the box disappears and the dialog is displayed.

Here is the user control code:

using System;
using System.Windows.Forms;

namespace j2associates.Tools.Winforms.Controls.DesignTimeSupport.SupportingClasses
{
    public partial class SimpleTest : UserControl
    {
        public bool Cancelled { get; set; }

        public SimpleTest()
        {
            InitializeComponent();
        }

        private void btnOK_Click(object sender, EventArgs e)
        {
            Cancelled = false;
            this.Hide();
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            Cancelled = true;
            this.Hide();
        }
    }
}

Here is the UITypeEditor code:

using System;
using System.Drawing.Design;
using System.Windows.Forms;
using System.Windows.Forms.Design;

using j2associates.Tools.Winforms.Controls.DesignTimeSupport.SupportingClasses;

namespace j2associates.Tools.Winforms.Controls.DesignTimeSupport.Editors
{
    internal class TimeElementsEditor : UITypeEditor // PropertyEditorBase<TimeElementsUserControl>
    {
        public override UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
        {
            return UITypeEditorEditStyle.DropDown;
        }

        public override object EditValue(System.ComponentModel.ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            if (value.GetType() == typeof(j2aTimePicker.TimeElementOptions))
            {
                var editorService = provider.GetService(typeof(IWindowsFormsEditorService)) as IWindowsFormsEditorService;
                if (editorService != null)
                {
                    using (var st = new SimpleTest())
                    {
                        editorService.DropDownControl(st);
                        if (st.Cancelled)
                        {
                            MessageBox.Show("Cancel");
                        }
                        else
                        {
                            MessageBox.Show("OK");
                        }
                        editorService.CloseDropDown();
                    }
                }
            }

            return value;
        }
    }
}

Any ideas and/or suggestions would be appreciated.

Answer 1

Sigh, it's always easy when you find it.

I needed to pass the IWindowsFormsEditorService in via an overloaded constructor, cache it and then call it's CloseDropdown method in the Button Click events instead of hiding the user control. It now works as expected.

/// <summary>
/// Displays an OK and Cancel button. When one is pressed, 
/// the dialog is closed and a message box is displayed.
/// The actual value of the property is unchanged throughout.
/// </summary>
/// <remarks>The ToolboxItem attribute prevents the control from being displayed in the ToolKit.</remarks>
[ToolboxItem(false)]
public partial class SimpleTest : UserControl
{
    public bool Cancelled { get; set; }

    private IWindowsFormsEditorService m_EditorService;

    // Require the use of the desired overloaded constructor.
    private SimpleTest()
    {
        InitializeComponent();
    }

    internal SimpleTest(IWindowsFormsEditorService editorService)
        : this()
    {
        // Cache the editor service.
        m_EditorService = editorService;
    }

    private void btnOK_Click(object sender, EventArgs e)
    {
        Cancelled = false;
        m_EditorService.CloseDropDown();
    }

    private void btnCancel_Click(object sender, EventArgs e)
    {
        Cancelled = true;
        m_EditorService.CloseDropDown();
    }
}

And here is the modified editor call:

using (var simpleTest = new SimpleTest(editorService))
{
    editorService.DropDownControl(simpleTest);
    MessageBox.Show(simpleTest.Cancelled ? "Cancelled" : "OK");
}