These Days I want to Use a new third party control, this control is a COM Control.

So I use Visual Studio auto create two namespace "CExcelLib " and "AxCExcelLib ". The "AxCExcelLib " is for Windows Forms. It's contain a control named "AxCExcel ". I can add this control to Tool Item Panel and it work well in my form in design view. It paints cells on my screen well.

And then, I want to expand it. so I create a new class named "RptControl " in namespace "RptControls ", that derived from "AxCExcel ". It compiled without an erro and a warning.
But when I try to add the my control to the panel , the problem comes. The Viusal Studio told me it can not find any controls in the dll file.

What's the problem? I create controls that derive from a .Net control often. There is no problem above.

Do there are some diffences bewtteen creating a control derive from .Net Control and COM Control, Thankes.


RptControls.RptControl -> AxCExcelLib.AxCExcel -> System.Windows.Forms.AxHost --> System.Windows.Forms.Control
|-> System.ComponentModel.ISupportInitialize
|-> System.ComponentModel.ICustomTypeDescriptor

Hi ebread,

As far as I know, there is few differences between creating a control derive from .Net Control and COM Control. In your case, you need to add a ToolboxItem attribute to the child control. This is the code snippet:

[ToolboxItem(true)]
public class RptControl : AxCExcel
{
}

You can ger more information about ActiveX control from: http://msdn.microsoft.com/en-us/library/aa751972(VS.85).aspx.

Let me know if this helps.
Aland Li

---

Please mark the replies as answers if they help and unmark if they don't. This can be beneficial to other community members reading the thread.

Does anyone know how to solve it?

Hi ebread,

As far as I know, there is few differences between creating a control derive from .Net Control and COM Control. In your case, you need to add a ToolboxItem attribute to the child control. This is the code snippet:

[ToolboxItem(true)]
public class RptControl : AxCExcel
{
}

You can ger more information about ActiveX control from: http://msdn.microsoft.com/en-us/library/aa751972(VS.85).aspx.

Let me know if this helps.
Aland Li

---

Please mark the replies as answers if they help and unmark if they don't. This can be beneficial to other community members reading the thread.

Yeh, it works well. Thanks.