Question

我想要实现一个按钮，当选中时会有一个下拉菜单，当取消选中时，此菜单就会消失。我的问题是，当它或菜单失去焦点时，我无法取消选中该复选框。

复选框的外观模式是按钮。

enter image description here

我的代码：

private void cbSettings_CheckedChanged(object sender, EventArgs e)
{
    if (cbSettings.Checked) {cmsSettings.Show(cbSettings, 0, cbSettings.Height);}
    else {cmsSettings.Hide();}
}

我试图在contextMenuStrip的VisibleChanged / Closed事件中取消选中复选框，但这导致菜单不隐藏（或隐藏并立即显示）。

Answer 1

我认为你取消选中上下文菜单关闭事件复选框的方法很好，你需要的是一些“事件取消逻辑”（c），如下所示：

private void OnContextClosing(object sender, EventArgs e)
{
    _cancel = true;
    cbSettings.Checked = false;
    _cancel = false;
}

private void cbSettings_CheckedChanged(object sender, EventArgs e)
{
    if(_cancel)
       return;

    if (cbSettings.Checked) {cmsSettings.Show(cbSettings, 0, cbSettings.Height);}
    else {cmsSettings.Hide();}
}

这将使CheckChanged事件无法重新检查您的复选框。

Answer 2

下面的示例当然不包括交换CheckBox的BackGroundImage以指示CheckState所需的代码。 “连线”的事件应该是显而易见的。希望这有用。

// tested in VS 2010 Pro, .NET 4.0 FrameWork Client Profile
// uses:
// CheckBox named 'checkBox1
// ContextMenuStrip named 'contextMenuStrip1
// TextBox named 'cMenuSelectionInfo for run-time checking of results

    // used to position the ContextMenuStrip    
    private Point cPoint;

    // context click ? dubious assumption that 'right' = context click
    private bool cmOpenedRight;

    // the clicked ToolStripMenuItem
    private ToolStripMenuItem tsMIClicked;

    private void checkBox1_MouseDown(object sender, MouseEventArgs e)
    {
        cmOpenedRight = e.Button == MouseButtons.Right;
    }

    private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        // positioning the CheckBox like this
        // is something in a 'real-world' example
        // you'd want to do in the Form.Load event !
        // unless, of course, you'd made the CheckBox movable
        if(checkBox1.Checked)
        {
            contextMenuStrip1.Show();
            cPoint = PointToScreen(new Point(checkBox1.Left, checkBox1.Top + checkBox1.Height));
            contextMenuStrip1.Location = cPoint;
        }
        else
        {
            contextMenuStrip1.Hide();
        }
    }

    private void contextMenuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
    {
        // assume you do not have to check for null here ?
        tsMIClicked = e.ClickedItem as ToolStripMenuItem;

        tbCbMenuSelectionInfo.Text = tsMIClicked + " : " + ! (tsMIClicked.Checked);
    }

    private void contextMenuStrip1_Closing(object sender, ToolStripDropDownClosingEventArgs e)
    {
        e.Cancel = checkBox1.Checked;
    }

    private void contextMenuStrip1_Closed(object sender, ToolStripDropDownClosedEventArgs e)
    {
        if (cmOpenedRight)
        {
            tbCbMenuSelectionInfo.Text += " : closed because : " + e.CloseReason.ToString();
        }
    }

CheckBox按钮和ContextMenuStrip用于下拉菜单

2 个答案: