Support: How to put a combo box into a Popup and prevent the dropdown from closing when clicked on it? : Syncfusion

Windows Forms Popup Control Container Editors Package

How to put a combo box into a Popup and prevent the dropdown from closing when clicked on it?

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Normally, when you put a combo box into a popup, the popup will be hidden when you click on the combo box drop-down. This is because the popup framework expects the windows you activate to be .NET control based, otherwise it just gives up.

To work around this problem, use a custom PopupControlContainer, as follows. Check out the inline comments.

public class CustomPopupControlContainer : PopupControlContainer

{

public CustomPopupControlContainer()

{

}

public CustomPopupControlContainer(IContainer container):this()

{

container.Add(this);

}

public override bool IsRelatedControl ( System.Windows.Forms.Control control , System.Boolean askPopupParent )

{

bool isrelated = base.IsRelatedControl(control, askPopupParent);

// This will be the case when native windows without dotnet wrappers are encountered

// like the combo box dropdown.

if(control == null && !isrelated)

{

// If so, then go ahead and get a dotnet parent control.

IntPtr hwnd = GetFocus();

// This method goes up the hierarchy looking for a dotnet parent.

Control dotnetParent = PopupUtils.GetADotNetParentControl(hwnd);

if(dotnetParent != null)

// if found then check if that is a related control, instead.

isrelated |= base.IsRelatedControl(dotnetParent, askPopupParent);

}

return isrelated;

}

[DllImport("user32.dll", CharSet=CharSet.Auto, CallingConvention=CallingConvention.Winapi)]

public static extern IntPtr GetFocus();

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true, CallingConvention=CallingConvention.Winapi)]

public static extern IntPtr GetParent(IntPtr hwnd);}