[英]Show control inside user control outside the boundaries of its parent
我有一個usercontrol,它有一個文本框和一個列表框,它使用它們為用戶提供自動完成功能。
但是,我希望將列表框繪制在用戶控件的邊界之外,以便在必須在用戶控件的邊緣附近繪制列表框時不會截斷它。 關於如何做到這一點的任何提示? 基本上我想要一個浮動在其容器控件邊界之外的列表框。
我能想到的唯一方法是在實例化時將對外部列表框的引用傳遞給用戶控件,然后操縱該列表框而不是將其放在用戶控件中,但我不喜歡這種方法。 提前致謝。
問題是,你無法逃避容器形式邊界,但你可以在其他地方托管你的控件。
這是我通過濫用ToolstripDropDown類(我用它來在大型企業應用程序中顯示datepickers)工作的方式:
/// <summary>
/// PopupHelper
/// </summary>
public sealed class PopupHelper : IDisposable
{
private readonly Control m_control;
private readonly ToolStripDropDown m_tsdd;
private readonly Panel m_hostPanel; // workarround - some controls don't display correctly if they are hosted directly in ToolStripControlHost
public PopupHelper(Control pControl)
{
m_hostPanel = new Panel();
m_hostPanel.Padding = Padding.Empty;
m_hostPanel.Margin = Padding.Empty;
m_hostPanel.TabStop = false;
m_hostPanel.BorderStyle = BorderStyle.None;
m_hostPanel.BackColor = Color.Transparent;
m_tsdd = new ToolStripDropDown();
m_tsdd.CausesValidation = false;
m_tsdd.Padding = Padding.Empty;
m_tsdd.Margin = Padding.Empty;
m_tsdd.Opacity = 0.9;
m_control = pControl;
m_control.CausesValidation = false;
m_control.Resize += MControlResize;
m_hostPanel.Controls.Add(m_control);
m_tsdd.Padding = Padding.Empty;
m_tsdd.Margin = Padding.Empty;
m_tsdd.MinimumSize = m_tsdd.MaximumSize = m_tsdd.Size = pControl.Size;
m_tsdd.Items.Add(new ToolStripControlHost(m_hostPanel));
}
private void ResizeWindow()
{
m_tsdd.MinimumSize = m_tsdd.MaximumSize = m_tsdd.Size = m_control.Size;
m_hostPanel.MinimumSize = m_hostPanel.MaximumSize = m_hostPanel.Size = m_control.Size;
}
private void MControlResize(object sender, EventArgs e)
{
ResizeWindow();
}
/// <summary>
/// Display the popup and keep the focus
/// </summary>
/// <param name="pParentControl"></param>
public void Show(Control pParentControl)
{
if (pParentControl == null) return;
// position the popup window
var loc = pParentControl.PointToScreen(new Point(0, pParentControl.Height));
m_tsdd.Show(loc);
m_control.Focus();
}
public void Close()
{
m_tsdd.Close();
}
public void Dispose()
{
m_control.Resize -= MControlResize;
m_tsdd.Dispose();
m_hostPanel.Dispose();
}
}
用法:
private PopupHelper m_popup;
private void ShowPopup()
{
if (m_popup == null)
m_popup = new PopupHelper(yourListControl);
m_popup.Show(this);
}
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